Rolling process of stainless steel surface roughening surface for torque cushion sheet of hybrid vehicle transmission

Abstract

The present application relates to a kind of hybrid vehicle gearbox torque buffer piece with stainless steel surface roughening surface rolling process, the thickness of the stainless steel strip is 2~10mm, width is 150~950mm;Finished product thickness is 0.5~3.0mm, width is 140~940mm, its rolling process includes the following steps: S1, pre-deformation rolling, S2, first cleaning, S3, first annealing, S4, roughening surface rolling, S5, second cleaning, S6, second annealing, S7, strip into warehouse;The rolling process is by pre-rolling deformation flat, roughness of the surface of high-efficiency transfer roughening roller is rolled asynchronously, the roughness parameter precision of finished product stainless steel strip is improved, to meet the roughness parameter requirement of torque buffer piece.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of stainless steel rough surface production, and relates to a rolling process for a rough surface of a stainless steel plate for a torque buffer sheet of a hybrid vehicle transmission, in particular to a rolling process for a rough surface of a stainless steel plate for a torque buffer sheet of a hybrid vehicle transmission. BACKGROUND

[0002] The hybrid vehicle skillfully combines the internal combustion engine and the electric motor, and the two work together to automatically switch the power mode according to different driving conditions, thereby reducing fuel consumption. In the city congestion, the vehicle frequently starts and stops, at this time, the hybrid vehicle relies on the electric motor to drive, avoiding the operation of the internal combustion engine in the low efficiency interval; when the vehicle speed is increased to high speed, it is automatically converted to internal combustion engine driving, ensuring the power output while significantly optimizing the fuel economy and effectively reducing the fuel consumption. This dual system driving mode not only reduces the carbon emissions of the automobile and reduces environmental pollution, but also reduces the frequency of use of the internal combustion engine, thereby reducing the wear of the engine and prolonging the service life of the engine, so that the hybrid vehicle shows unique advantages in environmental protection and durability.

[0003] The torque buffer sheet in the hybrid vehicle transmission is a core component, which transmits the output shaft torque to the input shaft through the friction sheet during normal operation to ensure operation, limits torque transmission to prevent damage when overloaded, and automatically restores torque transmission after load reduction, thereby improving work efficiency. The surface roughness parameters of the torque buffer sheet affect many key performances, and are related to the determination of torque regulation accuracy, the enhancement of wear resistance and the prolongation of service life. Good surface roughness parameters of the torque buffer sheet have the effect of buffering and damping, affect the power transmission efficiency, stability and accuracy, are related to wear durability and high temperature stability, and appropriate parameters can reduce vibration and noise, rapidly cut off power transmission in emergency situations, and improve safety performance.

[0004] The surface roughness parameters of the torque buffer sheet of the automobile transmission are very important. During production, the roughing process needs to ensure that the surface roughness of the stainless steel is uniform and constant before the buffer sheet is punched, which is the key to ensuring the performance of the torque buffer sheet and is of great significance to the stable operation of the automobile transmission. Through retrieval, the invention patent CN114433624B discloses a rough surface stainless steel cold rolling production method, which realizes the rough surface of the stainless steel through the processes of molten iron pretreatment, continuous casting of molten iron, slab rolling, annealing and pickling of hard rolled steel coil, roughening and flattening of the steel coil, and steel plate straightening, cleaning and cutting. The main process of realizing the rough surface is to roughen the surface of the strip through the flattening process after annealing and pickling of the hard rolled steel coil. Since the roughness parameters transferred to the surface of the strip by the flattening process are low in efficiency, and the strip has undergone micro-deformation and chrome plating treatment, the performance of the strip is changed, which is not conducive to the subsequent punching forming of the torque buffer sheet. Therefore, this method is not suitable for the application of the torque buffer sheet of the transmission.

[0005] Therefore, in order to solve the problem of constant surface roughness parameters of the torque buffer sheet of the automobile gearbox, and to facilitate the subsequent stamping process, the present application provides a new type of surface roughening rolling process for the torque buffer sheet of the gearbox of the hybrid electric vehicle. SUMMARY

[0006] Therefore, in order to solve the problem of constant surface roughness parameters of the torque buffer sheet of the automobile gearbox, and to facilitate the subsequent stamping process, the present application provides a new type of surface roughening rolling process for the torque buffer sheet of the gearbox of the hybrid electric vehicle.

[0007] To achieve the above purpose, the present application provides the following technical scheme:

[0008] A surface roughening rolling process for the torque buffer sheet of the gearbox of the hybrid electric vehicle, comprising the following steps:

[0009] S1, pre-deformation rolling: the stainless steel strip is rolled by multiple passes to form a pre-deformation semi-finished product with a thickness of 1.5-4.6mm, the single pass reduction is 5%-40%, the rolling pressure is 200-1000t, the rolling speed is 50-400m / min, and a pair of work rolls is replaced every pass;

[0010] S2, first cleaning: the pre-deformation semi-finished product is cleaned by alkali washing and ultrasonic cleaning process to remove the rolling oil and fine particles on the surface of the strip, and to prevent surface oxidation during annealing and subsequent roughening rolling affecting the uniformity of surface roughness;

[0011] S3, first annealing: the cleaned pre-deformation semi-finished product is subjected to full hydrogen atmosphere bright annealing, which softens the hard state stainless steel and facilitates the subsequent transfer of the surface roughness parameters of the roughening roller to the surface of the stainless steel;

[0012] S4, roughening rolling: the annealed pre-deformation semi-finished product is subjected to multiple asynchronous roughening rolling to form a finished product strip with a thickness of 0.5-3.0mm, the single pass reduction is 5%-40%, the rolling pressure is 50-1000t, the rolling speed is 40-300m / min, the asynchronous ratio is 1.05-1.2, the rolling process is carried out with paper padding on the winding side, a pair of roughening work rolls is replaced every pass, and the work roll surface is roughened by electric spark roughening process;

[0013] When using asynchronous rolling, the friction forces on the upper and lower surfaces of the deformation zone of the stainless steel are opposite, which is beneficial to the transfer of the roughness parameters of the roughened roller surface; full-range paper padding prevents the friction between the strips caused by large tension during rolling, which destroys the uniformity of the roughness parameters of the stainless steel surface; a pair of work rolls is replaced every pass, which enables high precision and stability of the roughened strip parameters;

[0014] S5, second cleaning: using alkaline cleaning and ultrasonic cleaning process to clean the finished strip;

[0015] S6, second annealing: the cleaned finished strip is subjected to full hydrogen atmosphere bright annealing to recrystallize the deformed stainless steel strip, which is beneficial to the subsequent stamping forming of the torque buffer sheet of the hybrid vehicle transmission;

[0016] S7, slitting and warehousing: the finished strip after annealing treatment is subjected to edge cutting and slitting treatment.

[0017] Further, the chemical composition of the hybrid vehicle transmission torque buffer sheet stainless steel strip in step S1 includes, by mass percentage: C: 0.05~1%, Si: 0.1~2%, Mn: 0.2~3%, P: 0.02~0.1%, S: 0.01~0.1%, Cr: 10~25%, the rest being Fe and other unavoidable impurities, the thickness of the hybrid vehicle transmission torque buffer sheet stainless steel strip is 2~10mm, and the width is 150~950mm.

[0018] Further, the synchronous rolling equipment used in the pre-deformation rolling in step S1 is a HL type six-roll reversible rolling mill, the work roll diameter is 90~120mm, and the work roll surface roughness is Ra 0.1~0.5μm.

[0019] During pre-rolling deformation, low surface roughness makes the surface of the stainless steel strip smooth, which does not affect the subsequent roughened surface rolling.

[0020] Further, the alkali concentration of the NaOH solution used in the first cleaning of step S1 and the second cleaning of step S5 is 20~30%, the ultrasonic frequency of the ultrasonic cleaning is 20KHz~60KHz, and the cleaning speed is 30~150m / min.

[0021] Further, the temperature of the first annealing in step S3 is 650~1100℃, the yield strength of the pre-deformation semi-finished strip after annealing is 180~400MPa, the tensile strength is 270~600MPa, and the elongation is 14~45%.

[0022] Further, the asynchronous rolling equipment used in the roughened surface rolling in step S4 is a four-roll reversible combined forming rolling mill, the roughened work roll diameter is 80~150mm, the surface roughness Ra is 2.0~6.0μm, Pc is 10~60, and Rsk is-0.5~0.8.

[0023] Further, the material of the texturing work roll in the step S4 is high-speed steel, and the composition includes, by mass percent: C: 0.85-1.25%, Si: 0.10-0.85%, Mn: 0.09-0.50%, S: ≤0.030%, P: ≤0.030%, Cr: 3.50-4.25%, Mo: 8.00-11.00%, W: 1.10-2.15%, V: 0.75-1.50%, Co: 7.65-8.95%, and the balance of Fe, and the surface hardness of the texturing work roll is HRC 65-67.

[0024] The electric spark texturing process can texture the surface of the work roll with high hardness, is not affected by the material of the work roll, can provide more accurate surface roughness and peak density of the work roll, and is beneficial to the stability of the surface parameters of the stainless steel strip during texturing rolling.

[0025] Further, the output power of the electric spark texturing process machine tool used for the electric spark texturing work roll in the step S4 is 40-50%, the frequency is 4KHz-400KHz, the voltage is 800-1000V, the current is 3-5A, the pulse width is 10-80μs, and the gap between the electrode and the workpiece is 0.01-0.15mm.

[0026] Further, the temperature of the second annealing in the step S6 is 750-880℃, and the yield strength of the finished strip after annealing is 205-250MPa, the tensile strength is 420-450MPa, and the elongation is 22-25%.

[0027] Further, the surface roughness Ra of the finished strip in the step S7 is 0.6-3.5μm, Pc is 10-90, and Rsk is -0.4-0.8, and the width of the finished strip after slitting is 140-940mm.

[0028] The beneficial effects of the present application are:

[0029] 1. The surface texturing rolling process for the torque buffer piece of the hybrid vehicle transmission disclosed in the present application adopts a low-roughness work roll for pre-rolling deformation, smooths the surface of the stainless steel strip, and is beneficial to the uniform and stable surface parameters of the subsequent texturing rolling of the stainless steel; high-hardness texturing work rolls are used for asynchronous rolling, the friction forces on the upper and lower surfaces of the stainless steel deformation zone are opposite, and the mechanical property parameters of the stainless steel strip are controlled through the first annealing, so that the surface parameters of the work roll are efficiently transferred to the surface of the stainless steel strip, and the surface roughness parameter precision of the finished stainless steel strip is improved.

[0030] 2. The disclosed torque buffer sheet for hybrid vehicle gearbox uses a stainless steel surface roughening rolling process, which adopts electric spark roughening process to roughen the surface of the work roll. The work roll surface with high hardness can be roughened, and is not affected by the material of the work roll. It can provide more accurate work roll surface roughness and peak density, which is beneficial to the stability of the surface parameters of the stainless steel strip during roughening rolling. Each pass changes the roll during roughening rolling, so that the roughness parameters transferred to the strip surface are stable, uniform and high in precision, meeting the surface roughness parameters required by the torque buffer sheet.

[0031] 3. The disclosed torque buffer sheet for hybrid vehicle gearbox uses a stainless steel surface roughening rolling process, which adopts two-pass alkaline washing and ultrasonic cleaning process to remove the influence of semi-finished product and fine impurity particles on the surface roughness of the stainless steel strip. During roughening rolling, paper is used as a cushion on the winding side to prevent friction between layers of stainless steel strips under the driving of winding side rolling tension, which causes changes in the surface roughness parameters of the stainless steel.

[0032] Other advantages, objects and features of the present application will be apparent to those skilled in the art from the following specification, in some degree, will be obvious to those skilled in the art from the following study, or can be taught from the practice of the present application. The objects and other advantages of the present application can be achieved and obtained by the following specification. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to make the purpose, technical scheme and advantages of the present application more clear, the preferred detailed description of the present application will be combined with the drawings as follows, in which:

[0034] Figure 1 The flow chart of the present application is a torque buffer sheet for hybrid vehicle gearbox;

[0035] Figure 2 The macroscopic surface of the work roll after electric spark roughening of the present application;

[0036] Figure 3 The macroscopic surface of the finished roughening strip of the present application;

[0037] Figure 4 The microcosmic surface of the finished roughening strip of the present application;

[0038] Figure 5 The surface profile curve of the finished roughening strip of the present application tested by roughness meter. DETAILED DESCRIPTION

[0039] Following, the embodiments of the present application will be described in detail by specific examples. Other advantages and effects of the present application can be easily understood by those skilled in the art from this description. The present application can also be implemented or applied by other different embodiments, and each detail in the description can be modified or changed based on different views and applications without departing from the spirit of the present application.

[0040] The chemical composition of the stainless steel strip in the embodiment of the present application is as follows: C: 0.1%, Si: 0.7%, Mn: 0.8%, P: 0.02%, S: 0.01%, Cr: 16%, and the rest is Fe and other inevitable impurities;

[0041] The chemical composition of the roughened work roll is as follows: C: 1.05-1.15%, Si: 0.15-0.65%, Mn: 0.15-0.40%, S: ≤0.030%, P: ≤0.030%, Cr: 3.50-4.25%, Mo: 9.00-10.00%, W: 1.15-1.85%, V: 0.95-1.35%, Co: 7.75-8.75%, and the rest is Fe. The surface hardness of the work roll is HRC 65-67. The synchronous rolling equipment is a HL type six-high reversible rolling mill, and the asynchronous rolling equipment is a four-high reversible combined forming rolling mill.

[0042] Example One

[0043] The stainless steel strip with a specification of 5×468 mm is selected for roughened surface rolling, and the final product specification is 1.8×232 mm roughened surface stainless steel strip.

[0044] The rolling process includes the following steps:

[0045] S1, pre-deformation rolling: the raw material is rolled through three passes of synchronous rolling to form a pre-deformation semi-finished product with a thickness of 2.6 mm×468 mm. The three-pass reduction is 20%, 20%, and 19%, respectively. The rolling pressure is 400 t, 420 t, and 420 t, respectively. The rolling speed is 120 m / min. The surface roughness of the work roll in the first two passes is Ra 0.3 μm, and the surface roughness of the work roll in the third pass is Ra 0.2 μm. The work roll diameter in the three passes is 120 mm.

[0046] S2, first cleaning: the pre-deformation semi-finished product is cleaned using a 30% NaOH solution, an ultrasonic cleaning with a frequency of 50 KHz, and a cleaning speed of 80 m / min.

[0047] S3, first annealing: the cleaned pre-deformation semi-finished product is subjected to bright annealing in a full hydrogen atmosphere, the annealing temperature is 930℃, the yield strength of the pre-deformation semi-finished product strip after annealing is 220MPa, the tensile strength is 398MPa, and the elongation is 24%.

[0048] S4, rough surface rolling: the pre-deformation semi-finished product after annealing is subjected to two-pass asynchronous rough surface rolling to form a finished product strip with a thickness of 1.8mm x 468mm, the two-pass reduction is 15%, 18% respectively, the rolling pressure is 240t, 260t respectively, the rolling speed is 70m / min, 65m / min respectively, the asynchronous ratio is 1.06, 1.08 respectively, the strip on the winding side is padded with paper throughout the rolling process, and the work roll with a diameter of 90mm is used for asynchronous rolling, the surface of the work roll is roughened by electric spark process, and the electric spark roughening process is as follows: the output power of the machine tool is 45%, the frequency is 200KHz, the voltage is 900V, the current is 4A, the pulse width is 60μs, and the gap between the electrode and the workpiece is 0.01mm. The surface parameters of the roughened work roll are Ra 4.0μm, Pc 30, Rsk 0.2, and the macro surface of the roughened work roll is as shown in Figure 2 .

[0049] S5, second cleaning: the finished product strip is cleaned by using a NaOH solution with a concentration of 25% for alkaline cleaning, a frequency of 30KHz for ultrasonic cleaning, and a cleaning speed of 70m / min.

[0050] S6, second annealing: the cleaned finished product strip is subjected to bright annealing in a full hydrogen atmosphere, the annealing temperature is 880℃, the yield strength of the finished product strip after annealing is 230MPa, the tensile strength is 430MPa, and the elongation is 24%.

[0051] S7, strip cutting and storage: the finished product strip after annealing is cut and divided into strips, the product specification is 1.8 x 232mm finished product strip, the surface roughness parameters of the strip are Ra 1.8μm, Pc 30, Rsk 0.2, the macro surface of the finished product strip is as shown in Figure 3 , the micro surface is as shown in Figure 4 , and the surface profile curve tested by a roughness meter is as shown in Figure 5 .

[0052] Example Two

[0053] A stainless steel strip with a specification of 3 x 470mm is selected for rough surface rolling, and the final finished product is a rough surface stainless steel strip with a specification of 1.2 x 234mm.

[0054] The rolling process includes the following steps:

[0055] S1, pre-deformation rolling: the raw material is rolled by two passes of synchronous rolling to form a pre-deformation semi-product with a thickness of 2.0 mm x 470 mm, the reduction of the two passes is 20% and 17% respectively, the rolling pressure is 430 t and 430 t respectively, the rolling speed is 130 m / min, the surface roughness of the work roll of the two passes is Ra 0.2 μm, and the diameter of the work roll of the two passes is 100 mm.

[0056] S2, first cleaning: the pre-deformation semi-product is cleaned by using a NaOH solution with a concentration of 25%, ultrasonic cleaning with a frequency of 60 KHz, and a cleaning speed of 70 m / min.

[0057] S3, first annealing: the cleaned pre-deformation semi-product is subjected to full hydrogen atmosphere bright annealing at an annealing temperature of 890 ℃, and the yield strength of the pre-deformation semi-product strip after annealing is 210 MPa, the tensile strength is 395 MPa, and the elongation is 28%.

[0058] S4, roughened surface rolling: the annealed pre-deformation semi-product is subjected to three passes of asynchronous roughened rolling to form a finished strip with a thickness of 1.2 mm x 470 mm, the reduction of the three passes is 20%, 15% and 12% respectively, the rolling pressure is 230 t, 210 t and 190 t respectively, the rolling speed is 70 m / min, 65 m / min and 65 m / min respectively, the asynchronous ratio is 1.08, 1.05 and 1.05 respectively, the winding side strip is padded with paper throughout the rolling process, and the asynchronous rolling uses a work roll with a diameter of 90 mm, the surface of the work roll is roughened by electric spark process, and the electric spark roughening process is as follows: the output power of the machine tool is 48%, the frequency is 240 KHz, the voltage is 880 V, the current is 5 A, the pulse width is 70 μs, and the gap between the electrode and the workpiece is 0.01 mm. The surface parameters of the roughened work roll are Ra 4.2 μm, Pc 35 and Rsk 0.4.

[0059] S5, second cleaning: the finished strip is cleaned by using a NaOH solution with a concentration of 25%, ultrasonic cleaning with a frequency of 25 KHz, and a cleaning speed of 65 m / min.

[0060] S6, second annealing: the cleaned finished strip is subjected to full hydrogen atmosphere bright annealing at an annealing temperature of 830 ℃, and the yield strength of the finished strip after annealing is 235 MPa, the tensile strength is 440 MPa, and the elongation is 22%.

[0061] S7, strip cutting and storage: the annealed finished strip is cut and divided into strips, and the product specification is a finished strip with a size of 1.2 x 234 mm.

[0062] Finally, it is to be explained that the above embodiments are only used to illustrate the technical solutions of the present application but not to limit the present application. Although the present application is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions, and all should be covered in the scope of the claims of the present application.

Claims

1. A rolling process for a roughened stainless steel surface on a torque buffer plate for a hybrid vehicle transmission, characterized in that, Includes the following steps: S1. Pre-deformation rolling: The stainless steel strip is rolled into a pre-deformed semi-finished product with a thickness of 1.5~4.6mm through multiple passes. The reduction per pass is 5%~40%, the rolling pressure is 200~1000t, the rolling speed is 50~400m / min, and a pair of work rolls are replaced for each pass. S2. First cleaning: The pre-deformed semi-finished product is cleaned by alkaline washing and ultrasonic cleaning processes to remove rolling oil and fine particulate impurities from the strip surface, and to prevent surface oxidation during annealing and subsequent roughening rolling from affecting the uniformity of surface roughness. S3, First annealing: The pre-deformed semi-finished product after cleaning is bright annealed in a full hydrogen atmosphere. Annealing softens the hard stainless steel by recrystallization, which is beneficial for the subsequent transfer of the surface roughness parameters of the texturing roller to the stainless steel surface. S4. Textured Rolling: The annealed pre-deformed semi-finished product is subjected to multi-pass asynchronous texturing rolling to produce a finished strip with a thickness of 0.5~3.0mm. The single-pass reduction is 5%~40%, the rolling pressure is 50~1000t, the rolling speed is 40~300m / min, and the speed ratio is 1.05~1.

2. During the rolling process, the strip on the winding side is padded with paper throughout the process. A pair of texturing work rolls are replaced for each pass, and the surface of the work rolls is texturized by electrical discharge texturing process. S5. Second cleaning: Clean the finished strip material using alkaline washing and ultrasonic cleaning processes. S6. Second annealing: The cleaned finished strip is subjected to bright annealing in a full hydrogen atmosphere to recrystallize the deformed stainless steel strip, which is beneficial for the subsequent stamping and forming of torque buffer sheets. S7. Slitting and Warehousing: The finished strip after annealing is trimmed and slid. In step S1, the synchronous rolling equipment used for pre-deformation rolling is an HL-type six-high reversible mill with a work roll diameter of 90~120mm and a work roll surface roughness of Ra 0.1~0.5μm; In step S4, the material of the texturing work roll in the texturing rolling process is high-speed steel, and its composition by mass percentage includes: C: 0.85-1.25%, Si: 0.10-0.85%, Mn: 0.09-0.50%, S: ≤0.030%, P: ≤0.030%, Cr: 3.50-4.25%, Mo: 8.00-11.00%, W: 1.10-2.15%, V: 0.75-1.50%, Co: 7.65-8.95%, with the balance being Fe. The surface hardness of the texturing work roll is HRC 65-67.

2. The stainless steel surface roughening rolling process for torque buffer plates in hybrid vehicle transmissions as described in claim 1, characterized in that, The chemical composition of the stainless steel strip used for the torque buffer plate of the hybrid vehicle transmission in step S1, by mass percentage, includes: C: 0.05~1%, Si: 0.1~2%, Mn: 0.2~3%, P: 0.02~0.1%, S: 0.01~0.1%, Cr: 10~25%, with the remainder being Fe and other unavoidable impurities. The thickness of the stainless steel strip used for the torque buffer plate of the hybrid vehicle transmission is 2~10mm, and the width is 150~950mm.

3. The stainless steel surface roughening rolling process for torque buffer plates in hybrid vehicle transmissions as described in claim 1, characterized in that, Both the first cleaning in step S2 and the second cleaning in step S5 use a NaOH solution with an alkaline concentration of 20-30%. The ultrasonic cleaning uses an ultrasonic frequency of 20KHz-60KHz and a cleaning speed of 30-150m / min.

4. The stainless steel surface roughening rolling process for torque buffer plates in hybrid vehicle transmissions as described in claim 3, characterized in that, In step S3, the temperature of the first annealing is 650~1100℃, and the yield strength of the pre-deformed semi-finished strip after annealing is 180~400MPa, the tensile strength is 270~600MPa, and the elongation is 14~45%.

5. The stainless steel surface roughening rolling process for torque buffer plates in hybrid vehicle transmissions as described in claim 1, characterized in that, In step S4, the asynchronous rolling equipment used for texturing the surface is a four-roll reversible combined forming mill. The diameter of the texturing work roll is 80~150mm, and the surface roughness Ra is 2.0~6.0μm, Rpc is 10~60, and Rsk is -0.5~0.

8.

6. The stainless steel surface roughening rolling process for torque buffer plates in hybrid vehicle transmissions as described in claim 5, characterized in that, In step S4, the output power of the EDM texturing machine tool used for the EDM texturing work roll is 40-50%, the frequency is 4KHz-400KHz, the voltage is 800-1000V, the current is 3-5A, the pulse width is 10-80μs, and the gap between the electrode and the workpiece is 0.01-0.15mm.

7. The stainless steel surface roughening rolling process for torque buffer plates in hybrid vehicle transmissions as described in claim 1, characterized in that, In step S6, the temperature for the second annealing is 750~880℃, and the yield strength of the finished strip after annealing is 205~250MPa, the tensile strength is 420~450MPa, and the elongation is 22~25%.

8. The stainless steel surface roughening rolling process for torque buffer plates in hybrid vehicle transmissions as described in claim 7, characterized in that, In step S7, the surface roughness Ra of the finished strip is 0.6~3.5μm, Rpc is 10~90, and Rsk is -0.4~0.

8. The width of the finished strip after the edge trimming and slitting process is 140~940mm.

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