A Control Method for the Peak Value Number of the Rolling Surface Roughness of EDT Automotive Sheets in a Six-High Aluminum Cold Rolling Mill

Abstract

The present invention discloses a control method for the peak number of surface roughness in the rolling of EDT automotive sheets by a six-high aluminum cold rolling mill, including the following: (1) using a six-high HC cold rolling mill with Ф480mm / Ф560mm / Ф1300mm*2050mm; (2) roughening the rolls: after roughening, the surface roughness of the rolls is Ra: 1.9 - 2.4μm, and Rpc: 100 - 120 / cm; (3) calibrating the rolling force at 1000 - 3000 KN with the roll gap close to zero, and calibrating the bending force of the work roll Fwb and the intermediate roll FImb to be 15% - 30%; (4) adopting a rolling force control mode. The present invention can effectively improve the peak number and reduce the production cost; the product quality of automotive sheets has been significantly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of automotive sheet rolling, and particularly relates to a control method for the peak number of surface roughness of EDT automotive sheets rolled by a six-high aluminum cold rolling mill. Background Art

[0002] With the need for domestic automotive lightweighting, energy conservation and emission reduction, the output of aluminum body sheets is increasing continuously. Aluminum alloy has the advantages of light weight, corrosion resistance, high specific strength and easy processing. Using automotive aluminum alloy sheets to produce automotive body panels can save energy and reduce emissions on the premise of ensuring safety. In particular, the outer body panels need to be painted; usually, dry lubrication leveling by a temper mill or wet lubrication rolling is used to obtain good coating performance. The surface of the strip after EDT treatment of the outer panel of the automotive sheet should meet the surface roughness Ra: 0.7 - 1.3 μm, and the peak number Rpc ≥ 40 / cm. With the improvement of quality requirements, higher requirements are placed on the surface of domestic automotive outer panels, which should meet the surface roughness Ra: 0.7 - 1.3 μm, and the peak number Rpc ≥ 70 / cm, so as to improve the coating performance of automotive sheets.

[0003] In the current development of the rolling process for automotive body panels, hot-rolled billets are used as the feedstock. The billets are made of 6-series aluminum alloy, with a thickness of 4.0 - 8.0 mm and a width of 950 - 2150 mm. The finished thickness is 0.8 - 3.0 mm. The main production process route is: melting and casting - sawing - milling - ingot heat treatment - 1 + 3 hot rolling - cold rolling - intermediate annealing - intermediate cold rolling - finished cold rolling EDT rolling - continuous annealing - aging - surface passivation treatment - packaging. The EDT rolling is carried out using a six-high HC cold rolling mill with a roll diameter of Ф480mm / Ф560mm / Ф1300mm*2050mm manufactured by China National Nonferrous Metals Industry Corporation. Usually, the operation is carried out according to the steps of grinding the rolls with a grinding wheel. The roughness of the strip is Ra: 0.7 - 1.3 μm and the peak count Rpc: 40 / cm - 60 / cm, which does not meet the requirement of the peak count Rpc ≥ 70 / cm. Therefore, it is necessary to upgrade the cold rolling mill equipment or replace the type of electrode for electro-discharge texturing to meet the requirements. The mill equipment manufacturer adds a secondary small hydraulic cylinder to the original hydraulic upper cylinder for rolling, reducing the wear caused by the force between the rolls. After wear, the original roughness Ra and peak count Rpc will decrease. In addition, the electro-discharge texturing (EDT) equipment manufacturer can also meet the requirements by using a new type of electrode (graphite-copper electrode) to increase the initial peak count Rpc of the roll texturing while keeping the roughness of the EDT roll unchanged, resulting in a decrease in the final roughness Rpc. In order to overcome the wear of the rolls of the cold rolling mill due to the force between the rolls, a finite difference model of the roll system is established based on the split beam theory for force analysis between the rolls, and the roll force values and the bending roll values during calibration and hot rolling are obtained (see patent number: ZL202010799058.2, a method for optimizing the bending roll value of a four-high aluminum rolling mill during hot rolling). By combining a reasonable rolling process, the original roughness of the EDT roll, the rolling speed, and the rolling control mode, the wear of the roll roughness in the transverse and longitudinal directions is reduced, so as to obtain a roughness Ra: 0.7 - 1.3 μm and a peak count Rpc: 70 / cm - 100 / cm that meet the requirements of automotive panels, effectively solving the problem that electro-discharge texturing requires purchasing new electrodes or modifying the equipment to increase the peak count and reduce production costs. Summary of the Invention

[0004] The purpose of the present invention is to provide a control method for the high peak count of the surface roughness of EDT automotive panels rolled by a six-high aluminum cold rolling mill, overcoming the control method of the prior art of the six-high cold rolling mill that the force between the rolls during rolling affects the peak count of the roll surface roughness. By formulating reasonable process operation steps, the surface quality of automotive panels is significantly improved, effectively solving the problem that electro-discharge texturing requires purchasing new electrodes or modifying the equipment to increase the peak count and reduce production costs.

[0005] To achieve the above purpose, the technical solution of the present invention is as follows:

[0006] (1) Six-high cold rolling mill: The working roll diameter is 450 - 480 mm, and the working roll surface width is 2050 mm; the intermediate roll diameter is 530 - 560 mm, and the intermediate roll surface width is 2050 mm; the backup roll diameter is 1230 - 1300 mm, and the backup roll surface width is 2000 mm; the roll profiles of all rolls are flat rolls; the roughness of the backup roll Ra ≤ 2.0 μm; the roughness of the intermediate roll Ra ≤ 1.0 μm, and the roughness of the working roll before texturing Ra ≤ 0.6 μm; rolling force F min = 1000 KN, rolling force F max = 20000 KN;

[0007] (2) Roll texturing: The working roll is textured by the electrode electro-discharge texturing process. The roughness Ra range of the textured working roll is 1.9 - 2.4 μm, and the Rpc range is 100 - 120 / cm;

[0008] (3) Set the rolling oil temperature of the six-high cold rolling mill to 35 - 42 °C; the rolling oil flow rate is 3000 - 4500 L / min, and the rolling oil pressure is 6 - 8 bar; the target flatness curve function is Y = -3x 2 , and the rolling speed V = 100 - 200 m / min; the purpose of speed control is to ensure that in the rolling force closed-loop mode, as the speed increases, the oil entering the roll gap increases, the rolling force decreases, and the roughness will also fluctuate accordingly.

[0009] (4) Roll gap zero calibration and warm roll parameter setting: The rolling force for roll gap zero calibration is 1000 - 3000 KN, and the bending force of the working roll F wb and the intermediate roll F Imb is 15% - 30%, that is, 150 - 300 KN, and the total bending force is 1000 KN; the purpose is to avoid uneven stress on the rolls, excessive wear of the roughness due to excessive force, and improve the lateral roughness uniformity of the rolls. And after calibration, no no-load warm rolling or hot rolling is carried out, and the purpose is to avoid wear of the roughness after the rolls are stressed, resulting in a decrease in roughness.

[0010] (5) Adopt the rolling force control mode: At the start of rolling, position control is first adopted, and the AGC thickness position feedback closed-loop control is input. After the speed reaches the set value and the thickness enters the target value, the rolling control mode is switched from the AGC thickness position feedback control closed-loop to the rolling force feedback control closed-loop. Although using the AGC thickness feedback closed-loop can also meet the requirements for the surface roughness Ra of automotive sheet products: 0.7 - 1.3 μm and the peak count Rpc: 70 / cm - 100 / cm; however, changes in the rolling speed will affect the fluctuation of the rolling force in the rolling length direction, thereby affecting the roughness fluctuation. The rolling control mode is switched from the AGC thickness position feedback control closed-loop to the rolling force feedback control closed-loop. The main purpose is to ensure the uniformity of the surface roughness of the roll and the strip during the rolling process, and to avoid the attenuation of the roughness Ra and the peak count Rpc during rolling due to roll wear caused by thickness or external force factors.

[0011] Further, in step (1), the six-high cold rolling mill is a six-high HC cold rolling mill with the model Ф480mm / Ф560mm / Ф1300mm*2050mm.

[0012] Further, step (2) is specifically as follows: Use an imported 12-electrode electric discharge texturing machine from the UK for roll texturing. The electrode type is PB102 copper electrode. The surface roughness Ra of the work roll before texturing is ≤0.6 μm; the surface roughness Ra range of the work roll after EDT texturing is: 1.9 - 2.4 μm; the Rpc range is: 100 - 120 / cm. The texturing parameters are shown in Table 1 below:

[0013] Table 1 EDT roll, PB102 copper electrode texturing parameters

[0014]

[0015] Further, based on the force analysis between the rolls, the force on the roll causes wear of the surface roughness of the roll. A finite difference model of the roll system is established by using the split beam theory. By calculating the deflections of the upper and lower roll systems, as well as the roll flattening between the rolls, and performing iterative calculations to obtain different combinations of rolling force and bending roll force. Determine the force distribution between the upper and lower work rolls, between the upper work roll and the intermediate roll, between the upper intermediate roll and the upper backup roll, between the lower work roll and the lower intermediate roll, and between the lower intermediate roll and the lower backup roll, and determine the roll gap calibration close to zero and the warm roll parameters as follows: The rolling force for roll gap calibration close to zero is 1000 - 3000 KN, the bending roll force of the calibrated work roll F wb and the intermediate roll is 15% - 30%, that is, 150 - 300 KN, the total bending roll force is 1000 KN. After the roll gap is calibrated close to zero, no warm roll is performed, otherwise the surface roughness of the roll will be worn and Ra and Rpc will decrease. If warm rolling is performed, the rolling force is 1000 - 3000 KN, the bending roll force of the calibrated work roll F Imb and the intermediate roll is wb and the intermediate roll is ImbIt is 15% - 30%, that is, 150 - 300 KN, and the total bending roll force is 1000 K, so that the uniformity of the transverse roughness meets the requirements.

[0016] Compared with the closest prior art, the technical solution provided by the present invention has the following excellent effects:

[0017] Break through the limitation of improving the peak number of roughness by using graphite electrodes or equipment transformation methods through EDT equipment. Through technical breakthroughs in the control method by combining rolling processes, operations, and equipment. Under the condition of the same roughness Ra, a high peak number Rpc is obtained, realizing the improvement of the quality of automotive sheets and reducing the cost of electro-discharge textured electrodes; the quality of automotive sheets is significantly improved and the market prospect is more competitive. Brief Description of the Drawings

[0018] Figure 1 For the surface roughness of the roll and strip after rolling by Method 1 and Method 2. Detailed Embodiments

[0019] The following further supplements and explains the present invention in combination with specific implementation schemes. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them.

[0020] Example 1

[0021] A control method for the high peak number of the surface roughness of EDT automotive sheets rolled by a six-high aluminum cold rolling mill, which includes the following steps:

[0022] (1) Main configurations of six-high cold rolling and steps for roll preparation

[0023] The cold rolling mill model is Ф480mm / Ф560mm / Ф1300mm*2050mm six-high HC cold rolling mill. The working roll diameter is 450 - 480 mm, the working roll surface width is 2050 mm, the intermediate roll diameter is 530 - 560 mm, and the intermediate roll surface width is 2050 mm; the backup roll diameter is 1230 - 1300 mm; the backup roll surface width is 2000 mm; the roll profiles of all rolls are flat rolls; the roughness of the backup roll Ra ≤ 2.0 μm; the roughness of the intermediate roll Ra ≤ 1.0 μm, and the roughness of the working roll before texturing Ra ≤ 0.6 μm; the rolling force F min = 1000 KN, the rolling force F max = 20000 KN.

[0024] (2) Use an imported 12-electrode electro-discharge texturing machine from the UK for roll texturing processing. The electrode type is PB102 copper electrode, and the roughness of the working roll before texturing Ra ≤ 0.6 μm; the roughness Ra range of the working roll after EDT texturing: 1.9 - 2.4 μm; the Rpc range: 100 - 120 / cm. The texturing parameters are shown in Table 1 below:

[0025] Table 1 EDT Roll, Texturing Parameters of PB102 Copper Electrode

[0026]

[0027] (3) Combining with the rolling process, the finished product thickness range is 0.8 - 3.0 mm, the reduction per pass of EDT rolling is 30 - 50 μm, the rolling oil temperature of the six-high rolling mill is set at 35 - 42 °C; the rolling oil flow rate is 3000 - 4500 L / min, and the rolling oil pressure is 6 - 8 bar; the target curve function of the strip shape is Y = -3x 2 , the rolling speed V = 100 - 200 m / min; among them, the purpose of speed control is to ensure that in the closed-loop mode of rolling force, as the speed increases, the oil entering the roll gap increases, the rolling force decreases, and the roughness will also fluctuate accordingly; the target function of the strip shape is y = ax 2 , a = -3 (constant), x: strip width, (-1 to +1).

[0028] (4) According to the force analysis between the rolls, the force on the roll causes wear on the surface roughness of the roll. By using the split beam theory to establish a finite difference model for the roll system. By calculating the deflections of the upper and lower roll systems, as well as the flattening between the rolls, and performing iterative calculations to obtain different combinations of rolling force and bending roll force. The force distribution between the upper and lower working rolls, between the upper working roll and the intermediate roll, between the upper intermediate roll and the upper backup roll, between the lower working roll and the lower intermediate roll, and between the lower intermediate roll and the lower backup roll, determine the roll gap zero calibration and warm roll parameters as follows: the rolling force for roll gap zero calibration is 1000 - 3000 KN, the bending roll force of the calibration working roll F wb and the intermediate roll F Imb is 15% - 30%, that is, 150 - 300 KN, the total bending roll force is 1000 KN, and no warm roll is carried out after the roll gap is set to zero, otherwise the surface roughness of the roll will be worn, and Ra and Rpc will decrease. If warm rolling is carried out, the rolling force is 1000 - 3000 KN, the bending roll force of the calibration working roll F wb and the intermediate roll F Imb is 15% - 30%, that is, 150 - 300 KN, the total bending roll force is 1000 K, so that the uniformity of the transverse roughness meets the requirements.

[0029] Adopt the roughness meter imported from the UK, model TAYLOR HOBSON SP128, the instrument range is 2.5 * 12.5 mm, the Rpc amplitude B = ±0.5 μm, and the surface roughness of the strip under different calibration forces and rolling forces is shown in Table 2 below:

[0030] Table 2 Surface Roughness of the Strip Produced by Using This Method under Different Calibration Rolling Forces

[0031]

[0032] As can be seen from the data in Table 2, with the increase of the rolling calibration force, when rolling according to the control method of the present invention, the surface roughness Ra and Rpc of the strip decrease accordingly, reaching the edge value of the surface roughness of 0.7 - 1.3 μm for automotive sheet products, and the minimum rolling force of the equipment is 1000 KN, and the gap between the rolling mills can be eliminated only during calibration. Therefore, controlling the calibration force to be set at 1000 - 3000 KN can ensure that the product roughness performance Ra and Rpc indicators meet the requirements.

[0033] (5) Adopt the rolling force control mode: At the start of rolling, position control is first adopted, and the AGC thickness position feedback closed-loop control is input. After the speed reaches the set value and the thickness enters the target value, the rolling control mode is switched from the AGC thickness position feedback control closed-loop to the rolling force feedback control closed-loop.

[0034] Comparison description 1: Under the condition of the same Ra of roughness, different rolling methods result in different surface peak counts Rpc of automotive sheet.

[0035] Method 1: For the 6014 aluminum alloy automotive sheet, the reduction per pass in EDT rolling is 30 - 50 μm. The working roll is textured using the roll texturing parameters in Table 1. After changing the roll, the roll gap is calibrated to zero. The rolling force for roll gap calibration to zero is 1000 - 3000 KN, and the bending force F wb of the work roll and the intermediate roll bending force F Imb is 15% - 30%, that is, 150 - 300 KN, and the total bending force is 1000 KN. After calibration, the no-load hot roll rolling force is 1000 - 3000 KN, and the bending force F wb of the work roll and the intermediate roll bending force F Imb is 15% - 30%, that is, 150 - 300 KN, and the total bending force is 1000 KN. The no-load hot roll time is 5 - 10 minutes; The roughness meter imported from the UK, model TAYLOR HOBSON SP128, with an instrument range of 2.5 * 12.5 mm, and the Rpc amplitude B = ±0.5 μm.

[0036] Method 2: According to the method of Example 1, for the 6014 aluminum alloy automotive sheet, the reduction per pass in EDT rolling is 30 - 50 μm. The working roll is textured using the roll texturing parameters in Table 1. After changing the roll, the roll gap is calibrated to zero. The rolling force for roll gap calibration to zero is 1000 - 3000 KN, and the bending force F wb of the work roll and the intermediate roll bending force F Imb is 15% - 30%, that is, 150 - 300 KN, and the total bending force is 1000 KN. After the roll gap is pressed against and calibrated, rolling is directly carried out; The roughness meter imported from the UK, model TAYLOR HOBSON SP128, with an instrument range of 2.5 * 12.5 mm, and the Rpc amplitude B = ±0.5 μm.

[0037] For the above two methods, the measured surface roughness of the roll and the surface roughness of the strip are shown in Table 3 andFigure 1 As shown in:

[0038] Table 3 PB102 Copper Electrode Texturing Table 1 Parameters Texturing Definition Ra = 2.0μm Surface roughness of the roll and strip surface after rolling the roll

[0039]

[0040] As can be seen from Table 3, after texturing, the surface roughness of the new roll is Ra = 1.9 - 2.4μm, Rpc = 100 - 120 / cm; after calibration and hot rolling, the roll roughness Ra is reduced to 1.71μm, Rpc = 80 / cm after rolling, and the roll roughness Ra of the unheated roll after calibration is reduced to 2.13μm, Rpc = 112 / cm; due to the attenuation of the roll roughness during calibration and hot rolling, under the condition of the same rolling process, the surface roughness of the strip after hot rolling is Ra = 0.68μm, Rpc = 63 / cm; the surface roughness of the strip without hot rolling is Ra = 1.0μm, Rpc = 100 / cm; it can be seen that the attenuation of the surface roughness of the roll and strip after rolling with method one after hot rolling is obvious, and the surface roughness Ra of the strip produced by the Ra = 2.0μm roll textured with the parameters in Table 1 cannot meet the product requirement of Ra = 0.7 - 1.3μm; the attenuation of the surface roughness of the roll and strip with method two without hot rolling is small, and the surface roughness of the product meets the product requirements and the Rpc peak number is high.

[0041] Method 3: Using Method 1, for EDT texturing with copper electrodes, the surface roughness Ra of the rolled surface cannot meet the requirements. It is necessary to increase the defined original roll roughness to Ra = 2.8μm, Rpc = 85 - 90 / cm, and the Rpc of the strip after rolling is ≥ 50 - 60 / cm. The electrode type is PB102 copper electrode, and the surface roughness Ra of the work roll before texturing is ≤ 0.6μm; the range of the surface roughness Ra of the roll after EDT texturing of the work roll with the defined original roll roughness Ra = 2.8μm is: 2.75 - 3.0μm; the range of Rpc is: 85 - 90 / cm. The texturing parameters are shown in Table 4 below. The reduction of the 6014 aluminum alloy automotive sheet in the EDT rolling pass is 30 - 50μm. The work roll is textured using the roll texturing parameters in Table 1. After changing the roll, zero calibration of the roll gap is carried out. The rolling force for zero calibration of the roll gap is 1000 - 3000KN, and the calibration work roll F wb and the bending force F of the intermediate roll Imb is 15% - 30%, that is, 150 - 300KN, and the total bending force is 1000KN. After calibration, the no-load hot rolling force is 1000 - 3000KN, and the calibration work roll F wb and the bending force F of the intermediate roll ImbIt is 15% - 30%, that is, 150 - 300 KN, the total roll bending force is 1000 KN, and the no-load hot roll time is 5 - 10 minutes; The roughness meter imported from the UK, model TAYLOR HOBSON SP128, with an instrument range of 2.5 * 12.5 mm and an Rpc amplitude B = ±0.5 μm, was used to measure the surface roughness of the roll and the strip as shown in Table 5:

[0042] Table 4 shows the texturing parameters of the EDT roll and the PB102 copper electrode, with Ra = 2.8 μm.

[0043]

[0044] Table 5 shows the surface roughness of the roll and the strip after rolling with the PB102 copper electrode textured with Ra = 2.8 μm

[0045]

[0046] It can be seen from Table 3 that if the warm roll method after calibration is adopted, the roll attenuation can be seen, making the surface roughness of the strip unable to meet the requirement of Ra = 0.7 - 1.3 μm; Therefore, through Method 3, the PB102 copper electrode is used to increase the original roll roughness Ra = 2.8 μm and Rpc = 85 - 90 / cm, so as to meet the product roughness requirement; However, as the Ra of the roll increases, the Rpc decreases somewhat.

[0047] Method 4: Electro-discharge texturing. As the Ra increases, the number of Rpc peaks of the roll decreases accordingly. Therefore, a new type of electrode, the graphite copper electrode, needs to be purchased to ensure that the number of strip peaks Rpc can be increased without adjusting the roughness. Each group of copper electrodes costs about 800 yuan per piece, and each group of graphite electrodes costs about 6800 yuan, with the cost increasing by 8 times and the consumption being much greater than that of copper electrodes. The reduction of the 6014 aluminum alloy automotive sheet in the EDT rolling pass is 30 - 50 μm. Using the roll texturing parameters in Table 3, the working roll is textured with a graphite electrode. After changing the roll, the roll gap is calibrated to zero. The rolling force for calibrating the roll gap to zero is 1000 - 3000 KN, and the calibration working roll F wb and the intermediate roll bending force F Imb is 15% - 30%, that is, 150 - 300 KN, the total roll bending force is 1000 KN, and directly enter rolling after calibrating the roll gap to be pressed against; The roughness meter imported from the UK, model TAYLOR HOBSON SP128, with an instrument range of 2.5 * 12.5 mm and an Rpc amplitude B = ±0.5 μm, was used to measure the surface roughness of the roll and the strip as shown in Table 6 and Table 7:

[0048] Table 6 shows the texturing parameters of the EDT roll with a graphite electrode. After texturing, the roll roughness Ra = 2.8 μm and Rpc = 100 - 110 / cm.

[0049]

[0050] Table 7 Definition of texturing of new graphite copper electrode Ra = 2.8μm Surface roughness of the roll and strip after rolling:

[0051]

[0052] Both Method 2 and Method 4 can obtain a roughness Ra of 0.7 - 1.3μm and a peak count Rpc of 70 / cm to 100 / cm. Method 2 effectively solves the problem that in electro-discharge texturing, new electrodes need to be purchased or the equipment needs to be modified to increase the peak count and reduce production costs. Moreover, when implemented according to the operation steps of Method 2, under the condition of the same surface roughness Ra in automotive sheet rolling, the Rpc peak count is higher than that of Method 3 using copper electrodes and Method 4 using graphite electrodes. Thus, it can be seen that Method 2 is a better solution to obtain a high peak count.

[0053] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are within the scope of protection of the pending claims of the present invention.

Claims

1. A control method for the peak value number of the rolling surface roughness of EDT automotive sheets by a six-high aluminum cold rolling mill, characterized in that: Including the following steps: (1)Six-high cold rolling mill: The working roll diameter is 450 - 480 mm, and the working roll surface width is 2050 mm; the intermediate roll diameter is 530 - 560 mm, and the intermediate roll surface width is 2050 mm; the backup roll diameter is 1230 - 1300 mm, and the backup roll surface width is 2000 mm; the roll profiles of all rolls are flat rolls; the roughness of the backup roll Ra ≤ 2.0 μm; the roughness of the intermediate roll Ra ≤ 1.0 μm, and the roughness of the working roll before texturing Ra ≤ 0.6 μm; the rolling force F min = 1000 KN, the rolling force F max = 20000 KN; (2) Roll texturing: The work roll is textured by the electrode electrical discharge texturing process. After texturing, the surface roughness Ra of the work roll ranges from 1.9 to 2.4 μm, and the Rpc ranges from 100 to 120 / cm; (3)Set the rolling oil temperature of the six-high cold rolling mill at 35 - 42 °C; the rolling oil flow rate at 3000 - 4500 L / min, and the rolling oil pressure at 6 - 8 bar; the target flatness curve function Y = -3x 2 , the rolling speed V = 100 - 200 m / min; (4) Roll gap calibration to zero and warm roll parameter setting: When calibrating the roll gap to zero, the rolling force is 1000 - 3000 KN. When calibrating the work roll F wb and the intermediate roll bending force F Imb is 15% - 30%, that is, 150 - 300 KN, and the total bending force is 1000 KN; and no no-load warm rolling or hot rolling is carried out after calibration; (5) Adopt the rolling force control mode: At the start of rolling, position control is first adopted, and the AGC thickness position feedback closed-loop control is input. After the speed reaches the set value and the thickness enters the target value, the rolling control mode is switched from the AGC thickness position feedback control closed-loop to the rolling force feedback control closed-loop.

2. The control method for the peak number of surface roughness in the rolling of EDT automotive sheets by a six-high aluminum cold rolling mill according to claim 1, characterized in that: In step (1), the six-high cold rolling mill is a six-high HC cold rolling mill with the model Ф480mm / Ф560mm / Ф1300mm*2050mm.

3. The control method for the peak number of surface roughness in the rolling of EDT automotive sheets by a six-high aluminum cold rolling mill according to claim 1, characterized in that: The electrode used in the electrode electrical discharge texturing process is a PB102 copper electrode.

4. The control method for the peak number of surface roughness in the rolling of EDT automotive sheets by a six-high aluminum cold rolling mill according to claim 2, characterized in that: The parameters of the electrode electrical discharge texturing process are: current is 2A, on / off time is 11 / 15 μs, electrode walking speed is 12 mm / min, electrode-roll gap position is 3.6 / 3.0 mm, roll rotation speed is 30 mm / min, electrode gain is 10, and the number of texturing passes is 3 - 5.

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