A method for controlling the low gloss stability of cold-rolled 5052 aluminum alloy strip surface

Abstract

The present invention relates to a method for controlling the low gloss stability of the surface of a cold-rolled 5052 aluminum alloy strip. The cold rolling production process comprises, in sequence, slab cold rolling, intermediate annealing, finished product cold rolling, degreasing agent cleaning, finished product annealing, finished product trimming, and packaging. The surface transverse roughness Ra of the first roller in the slab cold rolling is 0.8-1.0 μm; the finished product cold rolling is produced in two passes, the first pass being rolled using a second roller subjected to electric spark texturing, and the second pass using a third roller having a surface transverse roughness Ra of 0.35-0.45 μm. The rolling control method of the present invention can effectively reduce yield loss; solve the problem of scrap loss caused by unqualified gloss due to production operation and rolling conditions; and the method can also improve the color uniformity of the strip surface, effectively reduce the surface gloss of the aluminum alloy, and improve the gloss stability during the production process. The method is an environmentally friendly, reliable, simple, and easy-to-promote control method.

Description

Technical Field

[0001] The invention relates to a method for controlling the low gloss stability of the surface of a cold-rolled 5052 aluminum alloy strip. Background Art

[0002] At present, the company's products are widely used in electronic products, such as Huawei mobile phone cases, Apple mobile phone cases, laptop computer cases, mobile phone mid-plates and other products, requiring the color difference value B value ≤3.5, the upper and lower surface gloss 20° requirement 60-180GU, and the surface roughness Ra≤0.6μm; its glossiness requirement mainly affects the positioning needs of the laser light source for welding after the downstream stamping and forming of electronic products. High glossiness reduces the positioning accuracy and makes it difficult to scan and recognize QR codes. The surface of the aluminum plate needs to obtain a glossiness of 60-200GU at 20° on the upper and lower surfaces. At present, in order to obtain low-gloss products at home and abroad, strong acid or strong alkali is generally added to the strip surface during cleaning to etch it, and chemical treatment is used. In industrial applications, it has water treatment difficulties and the chemical agents are highly corrosive, posing certain safety and environmental risks to people and equipment. Therefore, the current strong alkali and strong acid chemicals for cleaning have been gradually replaced by neutral degreasing agents. When the etching is severe, the surface layer tissue is corroded and color difference and surface defects are easily produced.

[0003] In order to solve the above technical problems, the present invention proposes a method for controlling the low gloss stability of the surface of cold-rolled 5052 aluminum alloy strip, aiming to overcome the existing production process difficulties and provide an environmentally friendly, reliable, simple and easy-to-promote cold rolling control method. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a method for controlling the low gloss stability of the surface of a cold-rolled 5052 aluminum alloy strip.

[0005] In order to solve the above technical problems, the technical solution of the present invention is: a method for controlling the low gloss stability of the surface of a cold-rolled 5052 aluminum alloy strip, wherein the cold rolling production process is sequentially: blanking cold rolling, intermediate annealing, finished product cold rolling, degreasing agent cleaning, finished product annealing, finished product trimming, and packaging;

[0006] Cold rolling mills are used for both slab cold rolling and finished product cold rolling. The roll diameter range of cold rolling is 400-440mm, and the roll type is flat roll. The rolling oil temperature is 30±5℃, the rolling oil flow rate is 2500-3500L / min, and the rolling oil pressure is 8~10bar.

[0007] The slab is cold rolled through multiple passes to the intermediate annealing pass thickness, and the transverse roughness of the first roller surface used in the rolling process is Ra: 0.8~1.0μm;

[0008] The total processing rate after intermediate annealing is 20-25%. The finished product is cold rolled in two passes, and the inlet strip temperature is controlled at ≤45℃:

[0009] The first pass processing rate is 5%~7%, and the second roller is rolled using an electrospark texturing treatment, and the second roller surface transverse roughness Ra is 2.75~3.05μm;

[0010] The second pass processing rate is 10%~20%, and the third roller with a surface transverse roughness Ra: 0.35~0.45μm is used.

[0011] Preferably, the grinding process parameters of the first rolling roller are: using a grinder, the grinding fluid uses a mixture of coolant and water, the required concentration is: 3~6%, and the pH value is 8~10; the grinding wheel uses 60 mesh and the grinding wheel hardness is F grade, so that the lateral roughness of the surface of the first rolling roller is Ra: 0.8~1.0μm, and there is no visible color difference or scratch defect on the surface after grinding.

[0012] Preferably, the grinding process parameters of the second rolling roller are: surface treatment is performed using a 12-electrode electric spark texturing machine; the roughness of the original grinding wheel type roller is Ra≤0.2μm, and roughening is performed after grinding; and the surface lateral roughness of the second rolling roller is tested using a roughness meter to make Ra: 2.75~3.05μm.

[0013] Preferably, the cold rolling mill is produced using a six-roll 1850mm cold rolling mill.

[0014] Preferably, the cold rolling mill uses light white oil 100# base oil, and the additive is an alcohol additive, and the weight ratio of the alcohol additive to the base oil is 8.5-9.5%; 5052 aluminum alloy is used for production, and the mass fraction of chemical components is as follows: Si: 0.06-0.2%; Fe: 0.2-0.4%; Cu: 0.01-0.05%; Mn: 0.01-0.05%; Mg: 2.4-2.8%; Ti: 0.014-0.02%; the hot-rolled billet thickness is 2.5~5.1mm, and the finishing rolling temperature is 310~330℃.

[0015] Preferably, the blank is cold rolled through 3 to 5 passes to the thickness of the intermediate annealing pass.

[0016] Preferably, the grinding process parameters of the third roller are: using a grinder, using a mixture of coolant and water as the cutting fluid, with the required concentration of 3~6%, and a pH value of 8~10; using a 100-mesh grinding wheel with a grinding wheel hardness of F grade; making the lateral roughness of the surface of the third roller Ra: 0.35~0.45μm, and having no visible color difference or scratch defects on the surface after grinding.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The rolling control method of the present invention can effectively reduce the loss of finished product rate; solve the scrap loss caused by unqualified glossiness due to production operation and rolling conditions; the method can also improve the color uniformity of the strip surface, effectively reduce the glossiness of the aluminum alloy surface and improve the glossiness stability during the production process. It is an environmentally friendly, reliable, simple and easy to promote control method.

[0019] The present invention will be further described in detail below with reference to specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the change in speed length and glossiness during ordinary roller rolling in Scheme 2.

[0021] Figure 2 Schematic diagram of the change in speed-up length and glossiness during the rolling process in an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0024] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0025] This embodiment provides a method for controlling the low gloss stability of a cold-rolled 5052 aluminum alloy strip surface. The cold rolling production process comprises, in sequence, cogging cold rolling, intermediate annealing, finished product cold rolling (the total processing rate after intermediate annealing is controlled at 20-25%), degreasing agent cleaning (conductivity 18-22 ms / cm), finished product annealing, finished product trimming, and packaging.

[0026] Cold rolling mills are used for both slab cold rolling and finished product cold rolling. The roll diameter range of cold rolling is 400-440mm, and the roll type is flat roll. The rolling oil temperature is 30±5℃, the rolling oil flow rate is 2500-3500L / min, and the rolling oil pressure is 8-10bar. The finished product thickness range is 0.2-0.5mm, including:

[0027] The slab is cold rolled through multiple passes to the intermediate annealing pass thickness, and the transverse roughness of the first roller surface used in the rolling process is Ra: 0.8~1.0μm;

[0028] The total processing rate after intermediate annealing is 20-25%. The finished product is cold rolled in two passes, and the inlet strip temperature is controlled at ≤45℃:

[0029] The first pass processing rate is 5%~7%, and the second roller treated with electric spark texturing is used for rolling. The transverse roughness of the second roller surface is Ra: 2.75~3.05μm, and the surface roughness of the strip is Ra: 0.9-1.3μm;

[0030] The second pass (final rolling thickness pass) has a processing rate of 10%~20%. The third roller with a surface transverse roughness Ra of 0.35~0.45μm is used to obtain a qualified strip surface with a surface roughness Ra≤0.6μm, uniform surface roughness and low gloss.

[0031] In an embodiment of the present invention, the grinding process parameters of the first roller are as follows: a German Waldrich grinder is used, and the grinding fluid is a mixture of Castrol Syntilo 66 coolant and water, with the required concentration of 3-6% and a pH value of 8-10; an Atlantic brand 60-grit grinding wheel is used for grinding, and the grinding wheel hardness is F grade, so that the lateral roughness Ra of the surface of the first roller is 0.8-1.0 μm, and there is no visible color difference or scratch defect on the surface after grinding.

[0032] The larger the grinding wheel grit or the higher the roughness, the deeper and wider the cutting texture. Therefore, a 60-grit grinding wheel is used to grind the first roller to the required roller surface roughness Ra: 0.8-1.0μm. This ensures the depth of the roller cutting texture. As the number of rolling passes increases and the material work hardens, the oil pits on the strip surface continue to decrease. Grinding the first roller with a 60-grit grinding wheel creates a clear cutting texture on the strip surface, effectively slowing the increase in gloss. Using the grinding process in Table 1, the first roller surface has a transverse surface roughness Ra: 0.8-1.0μm. After grinding, there are no visible defects such as color difference and scratches on the surface.

[0033] Table 1 Grinding process parameters of the first roll

[0034]

[0035] In the embodiment of the present invention, the grinding process parameters of the second roller are as follows: surface treatment is performed using a British Sarclad 12 electrode electric spark texturing machine (i.e., EDT: Electro-Disharge Textured); a grinding wheel-type original roller with a roughness of Ra ≤ 0.2 μm is used, and after grinding, roughening is performed according to the process in Table 2; and a German Taylor Hobson Surtronic S128 roughness meter is used to test the transverse surface roughness of the second roller to Ra: 2.75~3.05 μm.

[0036] Table 2 Deburring process parameters

[0037]

[0038] The principle of EDM texturing is as follows: a high voltage is applied between the electrode and the roll to create a conductive spark. The heat generated by the spark melts the electrode and the roll surface, forming bubbles in the insulating oil. When the power is turned off, the bubbles burst, leaving a pit on the roll surface. Through pulsed discharge, repeated millions of times, the roll surface roughness and peak values ​​are controlled. Millions of physical and chemical reactions are layered together to form a truly disordered EDM surface. The EDM texturing surface is then transferred to the rolling mill to conduct the surface morphology. EDM texturing can produce a completely disordered strip surface with good repeatability. The pits formed on the strip surface after EDM texturing can quickly reduce the strip surface gloss, resulting in a uniform surface roughness.

[0039] In an embodiment of the present invention, the cold rolling mill is produced using a six-roll 1850mm cold rolling mill.

[0040] In an embodiment of the present invention, the cold rolling mill uses light white oil 100# base oil, and the additive is an alcohol additive, and the weight ratio of the alcohol additive to the base oil is 8.5-9.5%; 5052 aluminum alloy is used for production, and the mass fraction of chemical components is as follows: Si: 0.06-0.2%; Fe: 0.2-0.4%; Cu: 0.01-0.05%; Mn: 0.01-0.05%; Mg: 2.4-2.8%; Ti: 0.014-0.02%; the hot-rolled billet thickness is 2.5~5.1mm, and the finishing rolling temperature is 310~330℃.

[0041] In an embodiment of the present invention, the blank is cold rolled through 3 to 5 passes to the thickness of the intermediate annealing pass.

[0042] In the embodiment of the present invention, in order to ensure that the surface quality of the product is improved and the cutting marks are improved, and to avoid pits or color differences in the finished product due to too deep cutting marks, the grinding process parameters of the third roller are as follows: a German Waldrich grinder is used, and the cutting fluid is a mixture of Castrol Syntilo 66 coolant and water, with a required concentration of 3-6% and a pH value of 8-10; an Atlantic brand 100-grit grinding wheel is used for grinding, and the grinding wheel hardness is grade F; the grinding process in Table 3 is used to make the lateral roughness of the third roller surface Ra: 0.35-0.45 μm, and there are no visible defects such as color difference and scratches on the surface after grinding.

[0043] Table 3. Grinding process parameters of the third roll

[0044]

[0045] In the embodiments of the present invention, in order to better illustrate the inventiveness of the present invention, comparative schemes are listed as follows:

[0046]

[0047] Because the customer did not initially require glossiness, we used Option 1. Option 1 used ordinary rollers, resulting in significant fluctuations in the glossiness of the strip surface and poor stability.

[0048] Customers' gloss requirements have gradually increased to 60-200GU, with some requiring ≤180GU. Therefore, Scheme 2 was adopted for production. By improving roughness, grinding wheel type, and process parameters, Scheme 2 reduced fluctuations and improved strip surface gloss. At the same time, conventional grinding wheel production is affected by rolling lubrication conditions, which affect both rolling speed and lubrication conditions. A schematic diagram of the change in glossiness during conventional roller lifting in Scheme 2 is shown below. Figure 1 shown.

[0049] Scheme 3 adopts the patented control method to control the surface roughness of the strip, improve the stability of the strip surface gloss, and use EDT rolling to obtain low gloss; After the production of Scheme 3, the schematic diagram of the speed increase length and gloss change during the rolling process is as follows Figure 2 shown.

[0050] The surface glossiness of the rolls ground with ordinary grinding wheels is greatly affected by the rolling lubrication state. The surface glossiness of the strip rolled using this patented control method can obtain a more stable product with glossiness requirements by controlling the roughness of the EDT rolls and the roughness of the finished pass rolls.

[0051] The cold rolling mill's rolling acceleration and deceleration length generally reaches 500-1000 meters and the rolling speed is controlled at ≥700m / min, which has very strict requirements on production operation and rolling conditions; the loss in the acceleration and deceleration section is ≥1000 meters per roll; therefore, this patented rolling control method can effectively reduce the loss of finished product rate; solve the scrap loss caused by unqualified gloss due to production operation and rolling conditions; the method can also improve the color uniformity of the strip surface, effectively reduce the surface gloss of aluminum alloy and improve the gloss stability during the production process. It is an environmentally friendly, reliable, simple and easy to promote control method.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

Claims

1. A method for controlling the low gloss stability of a cold-rolled 5052 aluminum alloy strip surface, wherein the cold rolling production process comprises, in sequence, cogging cold rolling, intermediate annealing, finished product cold rolling, degreasing agent cleaning, finished product annealing, finished product trimming, and packaging, characterized in that: Cold rolling mills are used for both slab cold rolling and finished product cold rolling. The roll diameter range of cold rolling is 400-440mm, and the roll type is flat roll. The rolling oil temperature is 30±5℃, the rolling oil flow rate is 2500-3500L / min, and the rolling oil pressure is 8~10bar. The slab is cold rolled through multiple passes to the intermediate annealing pass thickness, and the transverse roughness of the first roller surface used in the rolling is Ra: 0.8~1.0μm; The total processing rate after intermediate annealing is 20-25%. The finished product is cold rolled in two passes, and the inlet strip temperature is controlled at ≤45℃: The first pass processing rate is 5%~7%, and the second roller is rolled using an electrospark texturing treatment, and the second roller surface transverse roughness Ra is 2.75~3.05μm; The second pass processing rate is 10%~20%, and the third roller with a surface transverse roughness Ra: 0.35~0.45μm is used.

2. The method for controlling the low gloss stability of the surface of a cold-rolled 5052 aluminum alloy strip according to claim 1, characterized in that: The grinding process parameters of the first rolling roller are as follows: a grinding machine is used, and the cutting fluid of the grinding machine is a mixture of coolant and water with the required concentration of 3~6% and a pH value of 8~10; a 60-mesh grinding wheel with a grinding wheel hardness of F grade is used, so that the lateral roughness of the surface of the first rolling roller is Ra: 0.8~1.0μm, and there is no visible color difference or scratch defect on the surface after grinding.

3. The method for controlling the low gloss stability of the surface of a cold-rolled 5052 aluminum alloy strip according to claim 1, characterized in that: The grinding process parameters of the second roller are as follows: surface treatment is performed using a 12-electrode electric spark texturing machine; the roughness of the original roller using a grinding wheel is Ra ≤ 0.2 μm, and roughening is performed after grinding; and the lateral roughness of the second roller surface is tested using a roughness meter to make Ra: 2.75~3.05 μm.

4. The method for controlling the low gloss stability of the surface of a cold-rolled 5052 aluminum alloy strip according to claim 1, characterized in that: The cold rolling mill is produced by a six-roll 1850mm cold rolling mill.

5. The method for controlling the low gloss stability of the surface of a cold-rolled 5052 aluminum alloy strip according to claim 1, characterized in that: The cold rolling mill uses light white oil 100# base oil, and the additive is an alcohol additive, which has a weight ratio of 8.5-9.5% to the base oil; it is produced using 5052 aluminum alloy, and the mass fraction of chemical components is %: Si: 0.06-0.2%; Fe: 0.2-0.4%; Cu: 0.01-0.05%; Mn: 0.01-0.05%; Mg ：2.4-2.8%； Ti: 0.014-0.02%; hot rolled billet thickness 2.5~5.1mm, finishing temperature 310~330℃.

6. The method for controlling the low gloss stability of the surface of a cold-rolled 5052 aluminum alloy strip according to claim 1, characterized in that: The slab is cold rolled through 3 to 5 passes to the thickness of the intermediate annealing pass.

7. The method for controlling the low gloss stability of the surface of a cold-rolled 5052 aluminum alloy strip according to claim 1, characterized in that: The grinding process parameters of the third roller are as follows: a grinding machine is used, a mixture of coolant and water is used as the cutting fluid, the required concentration is: 3~6%, and the pH value is 8~10; a 100-mesh grinding wheel is used, and the grinding wheel hardness is F grade; the lateral roughness Ra of the surface of the third roller is made to be: 0.35~0.45μm, and there is no visible color difference or scratch defects on the surface after grinding.

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