Preparation method of automotive 5-series aluminum alloy plate with high adhesive performance

Abstract

The invention discloses a preparation method of an automotive 5-series aluminum alloy plate with high adhesive performance, which comprises the following steps: (1) smelting aluminum alloy raw materials in a smelting furnace according to a ratio, and casting after slagging-off, degassing and filtering treatment to obtain an aluminum alloy ingot; (2) the aluminum alloy cast ingot is placed in a homogenizing furnace to be subjected to homogenizing treatment; (3) carrying out hot rolling on the homogenized aluminum alloy cast ingot, and then carrying out cold rolling treatment on a hot-rolled plate to obtain a cold-rolled plate; (4) the cold-rolled plate is subjected to continuous annealing, and an annealed 5-series aluminum alloy plate is obtained; and (5) the 5-series aluminum alloy plate in the annealing state is sequentially subjected to alkali washing and acid washing treatment, and the 5-series aluminum alloy plate for the automobile with the high adhesive performance is obtained. By optimizing alloy components and an annealing process, regulating and controlling the thickness of an oxidation film and adopting alkali washing and acid washing for surface treatment, the roughness of the surface of the plate is improved, the contact area of the plate and an adhesive layer is effectively increased, and therefore the adhesive performance is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aluminum alloy preparation, in particular to a preparation method of 5-series aluminum alloy sheet for automobile with high adhesive property. BACKGROUND

[0002] Aluminum alloy is widely used in the field of new energy vehicles due to its advantages of small density, good forming property, corrosion resistance and recyclability, such as hood inner and outer panels, door inner and outer panels, fender, structural parts, battery bottom plate, etc. The application of aluminum alloy sheet for automobile generally includes stamping, welding, painting, etc. The welding process includes laser welding, spot welding, self-piercing riveting, and adhesive bonding, and the connecting materials are not limited to aluminum-aluminum connection, but may also be aluminum-steel connection and aluminum-composite material connection. Spot welding and self-piercing riveting are usually suitable for metal-metal connection, and adhesive bonding is suitable for metal-metal and metal-nonmetal connection. Adhesive bonding has the following advantages: the connecting surfaces of the connecting materials do not produce stress concentration, the stress is relatively uniform; the adhesive is relatively light, which can reduce the weight to a certain extent; the temperature used in adhesive bonding is not high, which does not affect the material due to high temperature environment. Although adhesive bonding has the above advantages, the adhesive strength is affected by many factors, in addition to the composition of the adhesive, the structure, performance and surface state of the aluminum alloy sheet also affect the bonding strength. SUMMARY

[0003] To solve the above technical problems, the present application provides a preparation method of 5-series aluminum alloy sheet for automobile with high adhesive property.

[0004] The technical scheme adopted by the present application is as follows:

[0005] A preparation method of 5-series aluminum alloy sheet for automobile with high adhesive property, comprising the following steps:

[0006] (1) Melting and casting: the raw materials for preparing the 5-series aluminum alloy sheet for automobile are proportioned according to the following weight percentages: Si 0.04-0.08%, Fe 0.10-0.20%, Cu 0.02-0.08%, Mn 0.30-0.40%, Mg 2.8-3.2%, Cr 0.15-0.25%, and the rest is Al and other unavoidable impurities. Then the aluminum alloy raw materials after proportioning are placed in a melting furnace for melting, and after slagging, degassing and filtering, casting is performed to obtain aluminum alloy ingots;

[0007] (2) Homogenization: the aluminum alloy ingots are placed in a homogenization furnace for homogenization treatment;

[0008] (3) rolling: the homogenized aluminum alloy ingot is firstly subjected to hot rolling, the hot rolling coiling temperature is 320-350℃, and the coiling thickness is 5-7mm, then the hot-rolled plate is subjected to cold rolling treatment to obtain a cold-rolled plate;

[0009] (4) annealing: the cold-rolled plate is subjected to continuous annealing to obtain an annealed 5-series aluminum alloy plate;

[0010] (5) surface treatment: the annealed 5-series aluminum alloy plate is subjected to alkaline washing and acid washing treatment in sequence to obtain a 5-series aluminum alloy plate for automobile with high adhesive property.

[0011] Further, the homogenization temperature in the step (2) is 510-530℃, and the homogenization time is 6-10h.

[0012] Further, the hot rolling process in the step (3) is 1+5 hot rolling, that is, after one hot rough rolling, five continuous rolling is carried out.

[0013] Further, the cold rolling processing rate during cold rolling in the step (3) is 60%-70%.

[0014] Further, the annealing temperature during annealing in the step (4) is 480-500℃, and the linear speed is 35-40m / min.

[0015] Further, the alkaline washing solution in the step (5) is a mixed solution of sodium hydroxide and potassium hydroxide, and the pH value is 10.5-11.5; the acid washing solution is a mixed solution of sulfuric acid and hydrofluoric acid, and the pH value is 4.0-4.5, and in the acid washing solution, the volume ratio of sulfuric acid to hydrofluoric acid is 5-7:1.

[0016] Further, the alkaline washing temperature in the step (5) is 50-65℃, and the linear speed is 35-45m / min; the acid washing temperature is 50-65℃, and the linear speed is 35-45m / min.

[0017] Further, the 5-series aluminum alloy plate for automobile with high adhesive property obtained in the step (4) has an oxide film thickness of not more than 500nm.

[0018] Further, the 5-series aluminum alloy plate for automobile with high adhesive property obtained in the step (5) has a roughness of 0.4-0.52μm.

[0019] In the above technical solution of the present application, the adhesive property of the 5-series aluminum alloy plate for automobile is improved through the following aspects:

[0020] In the first aspect, the alloy composition is optimized, the thickness of the oxide film generated in the environment is reduced by reducing the content of Mg element, and the size and distribution of the Al6(FeMn) phase are controlled by reducing the content of Fe and Mn elements and increasing the content of Cr element, so that the oxide film layer is more uniform, and increasing the content of Cr element also helps to ensure the strength and formability of the plate;

[0021] In the second aspect, the thickness of the oxide film after annealing of the plate is controlled to prevent the thickness of the oxide film from being too large on the basis of ensuring the mechanical properties of the plate by optimizing the annealing process.

[0022] In the third aspect, on the basis of the above-mentioned alloy optimization, annealing process optimization for controlling the thickness and uniformity of the oxide film, the surface of the plate is cleaned as much as possible by combining alkali washing and acid washing, and the etching amount of the surface of the plate is increased and the roughness of the surface of the plate is increased by adjusting the temperature and linear speed of alkali washing and acid washing, so as to effectively increase the contact area between the surface of the plate and the adhesive layer, thereby improving the adhesive property.

[0023] The beneficial effects of the present application are as follows:

[0024] The present application provides a preparation method of a 5-series aluminum alloy plate for automobiles with high adhesive property, the thickness of the oxide film is controlled by optimizing the alloy composition and the annealing process, and the surface of the plate is treated by alkali washing and acid washing to increase the roughness of the surface of the plate, effectively increase the contact area between the surface of the plate and the adhesive layer, so that the plate has high strength and high formability, and the adhesion between the plate and the adhesive is enhanced, and the adhesive property of the plate is improved; and by changing the organization, performance and surface state of the plate, the requirements for the type and performance of the adhesive can be reduced, and the adaptability of the plate and the adhesive is improved. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0026] Figure 1 The process flow chart of the present application. DETAILED DESCRIPTION

[0027] The present application provides a preparation method of a 5-series aluminum alloy plate for automobiles with high adhesive property, in order to make the purpose, technical scheme and effect of the present application more clear and definite, the present application will be further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0028] It should be noted that the ratio of potassium hydroxide and sodium hydroxide in the alkaline solution in the following examples is not limited, as long as the pH range defined in the present application is reached to achieve good alkaline cleaning effect; the volume ratio of sulfuric acid and hydrofluoric acid in the pickling solution in the following examples needs to reach 5-7:1 (calculated by pure substance), and the pH range defined in the present application needs to be reached to achieve good pickling effect.

[0029] Example 1

[0030] Referring to Figure 1 , the 5-series aluminum alloy sheet for automobile with high adhesive property is prepared, and the steps are as follows:

[0031] (1) Melting and casting: the raw materials for preparing the 5-series aluminum alloy sheet for automobile are proportioned according to the following weight percentage: Si 0.06%, Fe 0.15%, Cu 0.05%, Mn 0.35%, Mg 3.2%, Cr 0.16%, and the rest is Al and other inevitable impurities. Then the aluminum alloy raw materials after proportioning are placed in a melting furnace for melting, and after slagging, degassing and filtering treatment, casting is carried out to obtain aluminum alloy ingot;

[0032] (2) Homogenization: the aluminum alloy ingot is placed in a homogenization furnace for homogenization treatment, and the homogenization temperature is 520℃ and the homogenization time is 8h;

[0033] (3) Rolling: the aluminum alloy ingot after homogenization treatment is directly hot-rolled, and the hot rolling process is 1+5 hot rolling, that is, after one hot rough rolling, five continuous rolling is carried out, and the hot rolling coiling temperature is 320℃ and the coiling thickness is 5mm. Then the hot-rolled sheet is subjected to multi-pass cold rolling treatment, and the cold rolling reduction is 67%, to obtain a cold-rolled sheet with a thickness of 1.65mm;

[0034] (4) Annealing: the cold-rolled sheet is annealed in a continuous annealing line, and the annealing temperature is 500℃ and the line speed is 36m / min, to obtain the 5-series aluminum alloy sheet in annealed state;

[0035] (5) Surface treatment: the 5-series aluminum alloy sheet in annealed state is sequentially subjected to alkaline cleaning and pickling treatment, and the alkaline cleaning solution is a mixed solution of sodium hydroxide and potassium hydroxide, with a pH value of 10.5, an alkaline cleaning temperature of 52℃ and a line speed of 36m / min; the pickling solution is a mixed solution of sulfuric acid and hydrofluoric acid, and the volume ratio of sulfuric acid to hydrofluoric acid in the pickling solution is 6:1, the pH value is 4.5, the pickling temperature is 54℃, and the line speed is 36m / min, to obtain the 5-series aluminum alloy sheet for automobile with high adhesive property.

[0036] Example 2

[0037] The embodiment prepares the 5 series aluminum alloy sheet for automobile with high adhesive property, and the steps are as follows:

[0038] (1) Melting and casting: the raw materials for preparing the 5 series aluminum alloy sheet for automobile are proportioned according to the following weight percentage, Si 0.07%, Fe 0.13%, Cu 0.07%, Mn 0.32%, Mg 3.0%, Cr 0.20%, the rest is Al and other inevitable impurities, then the aluminum alloy raw materials after proportioning are placed in a melting furnace for melting, after slagging, degassing and filtering treatment, casting is carried out, and an aluminum alloy ingot is obtained;

[0039] (2) Homogenization: the aluminum alloy ingot is placed in a homogenization furnace for homogenization treatment, the homogenization temperature is 530℃, and the homogenization time is 6h;

[0040] (3) Rolling: the aluminum alloy ingot after homogenization treatment is directly hot-rolled, the hot rolling process is 1+5 hot rolling, that is, after one hot rough rolling, five continuous rolling is carried out, the hot rolling coiling temperature is 350℃, and the coiling thickness is 7mm, then the hot rolled sheet is subjected to multi-pass cold rolling treatment, the cold rolling processing rate is 70%, the cold rolled sheet is obtained, and the sheet thickness is 2.1mm;

[0041] (4) Annealing: the cold rolled sheet is annealed in a continuous annealing line, the annealing temperature is 490℃, and the line speed is 38m / min, and the 5 series aluminum alloy sheet in the annealed state is obtained;

[0042] (5) Surface treatment: the 5 series aluminum alloy sheet in the annealed state is sequentially subjected to alkali washing and acid washing treatment, the alkali washing solution is sodium hydroxide and potassium hydroxide, the pH value is 11, the alkali washing temperature is 56℃, and the line speed is 40m / min; the acid washing solution is sulfuric acid and hydrofluoric acid, and the volume ratio of sulfuric acid to hydrofluoric acid in the acid washing solution is 7:1, the pH value is 4.0, the acid washing temperature is 59℃, the line speed is 40m / min, and the 5 series aluminum alloy sheet for automobile with high adhesive property is obtained.

[0043] Example 3

[0044] The embodiment prepares the 5 series aluminum alloy sheet for automobile with high adhesive property, and the steps are as follows:

[0045] (1) Melting and casting: the raw materials for preparing the 5 series aluminum alloy sheet for automobile are proportioned according to the following weight percentage, Si 0.08%, Fe 0.12%, Cu 0.06%, Mn 0.33%, Mg 2.8%, Cr 0.19%, the rest is Al and other inevitable impurities, then the aluminum alloy raw materials after proportioning are placed in a melting furnace for melting, after slagging, degassing and filtering treatment, casting is carried out, and an aluminum alloy ingot is obtained;

[0046] (2) homogenization: the aluminum alloy ingot is placed in a homogenizing furnace for homogenization treatment, the homogenization temperature is 510°C, and the homogenization time is 10h;

[0047] (3) rolling: the aluminum alloy ingot after homogenization treatment is directly hot-rolled, the hot-rolling process is 1+5 hot-rolling, that is, after one hot rough rolling, five continuous rolling is carried out, the hot-rolling coiling temperature is 320°C, and the coiling thickness is 5mm, then the hot-rolled plate is subjected to multi-pass cold rolling treatment, the cold rolling processing rate is 60%, the cold-rolled plate is obtained, and the plate thickness is 2.0mm;

[0048] (4) annealing: the cold-rolled plate is subjected to continuous annealing line annealing, the annealing temperature is 480°C, and the line speed is 40m / min, and the 5 series aluminum alloy plate in the annealed state is obtained;

[0049] (5) surface treatment: the 5 series aluminum alloy plate in the annealed state is subjected to alkaline washing and acid washing treatment in sequence, the alkaline washing solution is sodium hydroxide and potassium hydroxide, the pH value is 11.5, the alkaline washing temperature is 65°C, and the line speed is 45m / min; the acid washing solution is sulfuric acid and hydrofluoric acid, and the volume ratio of sulfuric acid to hydrofluoric acid in the acid washing solution is 5:1, the pH value is 4.0, the acid washing temperature is 63°C, the line speed is 45m / min, and the 5 series aluminum alloy plate for automobiles with high adhesive property is obtained.

[0050] Comparative Example 1

[0051] The present comparative example prepares a 5 series aluminum alloy plate for automobiles, and the steps are as follows:

[0052] (1) melting and casting: the raw materials for preparing the 5 series aluminum alloy plate for automobiles are proportioned according to the following weight percentage: Si 0.06%, Fe 0.15%, Cu 0.05%, Mn 0.35%, Mg 3.8%, Cr 0.16%, and the rest is Al and other inevitable impurities, then the aluminum alloy raw materials after proportioning are placed in a melting furnace for melting, and after slagging, degassing and filtering treatment, casting is carried out, and an aluminum alloy ingot is obtained;

[0053] (2) homogenization: the aluminum alloy ingot is placed in a homogenizing furnace for homogenization treatment, the homogenization temperature is 520°C, and the homogenization time is 8h;

[0054] (3) rolling: the aluminum alloy ingot after homogenization treatment is directly hot-rolled, the hot-rolling process is 1+5 hot-rolling, that is, after one hot rough rolling, five continuous rolling is carried out, the hot-rolling coiling temperature is 320°C, and the coiling thickness is 5mm, then the hot-rolled plate is subjected to multi-pass cold rolling treatment, the cold rolling processing rate is 67%, the cold-rolled plate is obtained, and the plate thickness is 1.65mm;

[0055] (4) annealing: the cold-rolled plate is annealed by a continuous annealing line, the annealing temperature is 500°C, and the linear speed is 36 m / min, to obtain the 5-series aluminum alloy plate in an annealed state;

[0056] (5) surface treatment: the 5-series aluminum alloy plate in an annealed state is sequentially subjected to alkali washing and acid washing treatment, the alkali washing solution is sodium hydroxide and potassium hydroxide, the pH value is 10.5, the alkali washing temperature is 52°C, and the linear speed is 36 m / min; the acid washing solution is sulfuric acid and hydrofluoric acid, and the volume ratio of sulfuric acid to hydrofluoric acid in the acid washing solution is 6:1, the pH value is 4.5, the acid washing temperature is 54°C, the linear speed is 36 m / min, to obtain the 5-series aluminum alloy plate for automobiles with high adhesive performance.

[0057] Comparative Example 2

[0058] This comparative example prepares a 5-series aluminum alloy plate for automobiles, the steps are as follows:

[0059] (1) melting and casting: the raw materials for preparing the 5-series aluminum alloy plate for automobiles are proportioned according to the following weight percentages, Si 0.06%, Fe 0.30%, Cu 0.05%, Mn 0.50%, Mg 3.2%, Cr 0.16%, and the rest is Al and other unavoidable impurities, then the aluminum alloy raw materials after proportioning are placed in a melting furnace for melting, and after slagging, degassing and filtering treatment, casting is carried out, to obtain an aluminum alloy ingot;

[0060] (2) homogenization: the aluminum alloy ingot is placed in a homogenization furnace for homogenization treatment, the homogenization temperature is 520°C, and the homogenization time is 8h;

[0061] (3) rolling: the aluminum alloy ingot after homogenization treatment is directly subjected to hot rolling, the hot rolling process is 1+5 hot rolling, that is, after one hot rough rolling, five continuous rolling is carried out, the hot rolling coiling temperature is 320°C, and the coiling thickness is 5mm, then the hot-rolled plate is subjected to multi-pass cold rolling treatment, the cold rolling reduction is 67%, to obtain a cold-rolled plate, and the plate thickness is 1.65mm;

[0062] (4) annealing: the cold-rolled plate is annealed by a continuous annealing line, the annealing temperature is 500°C, and the linear speed is 36 m / min, to obtain the 5-series aluminum alloy plate in an annealed state;

[0063] (5) surface treatment: the 5 series aluminum alloy plate in annealed state is sequentially subjected to alkali washing and acid washing treatment, and the alkali washing solution is sodium hydroxide and potassium hydroxide, the pH value is 10.5, the alkali washing temperature is 52℃, and the linear speed is 36m / min; the acid washing solution is sulfuric acid and hydrofluoric acid, and in the acid washing solution, the volume ratio of sulfuric acid to hydrofluoric acid is 6:1, the pH value is 4.5, the acid washing temperature is 54℃, and the linear speed is 36m / min, to obtain the 5 series aluminum alloy plate for automobile with high adhesive property.

[0064] Comparative Example 3

[0065] The present comparative example prepares a 5 series aluminum alloy plate for automobile, and the steps are as follows:

[0066] (1) melting and casting: the raw materials for preparing the 5 series aluminum alloy plate for automobile are proportioned according to the following weight percentage: Si 0.06%, Fe 0.15%, Cu 0.05%, Mn 0.35%, Mg 3.2%, Cr 0.16%, and the rest is Al and other inevitable impurities, then the aluminum alloy raw materials after proportioning are placed in a melting furnace for melting, and after slagging, degassing and filtering treatment, casting is carried out to obtain aluminum alloy ingot;

[0067] (2) homogenization: the aluminum alloy ingot is placed in a homogenization furnace for homogenization treatment, the homogenization temperature is 520℃, and the homogenization time is 8h;

[0068] (3) rolling: the aluminum alloy ingot after homogenization treatment is directly hot-rolled, the hot rolling process is 1+5 hot rolling, that is, after one hot rough rolling, five continuous rolling is carried out, the hot rolling coiling temperature is 320℃, and the coiling thickness is 5mm, then the hot-rolled plate is subjected to multi-pass cold rolling treatment, and the cold rolling reduction is 67%, to obtain a cold-rolled plate with a thickness of 1.65mm;

[0069] (4) annealing: the cold-rolled plate is annealed in a continuous annealing line, the annealing temperature is 520℃, and the linear speed is 30m / min, to obtain a 5 series aluminum alloy plate in annealed state;

[0070] (5) surface treatment: the 5 series aluminum alloy plate in annealed state is sequentially subjected to alkali washing and acid washing treatment, and the alkali washing solution is sodium hydroxide and potassium hydroxide, the pH value is 10.5, the alkali washing temperature is 52℃, and the linear speed is 36m / min; the acid washing solution is sulfuric acid and hydrofluoric acid, and in the acid washing solution, the volume ratio of sulfuric acid to hydrofluoric acid is 6:1, the pH value is 4.5, the acid washing temperature is 54℃, and the linear speed is 36m / min, to obtain the 5 series aluminum alloy plate for automobile with high adhesive property.

[0071] Comparative Example 4

[0072] A 5-series aluminum alloy sheet for automobile was prepared in the following steps:

[0073] (1) Melting and casting: the raw materials for preparing the 5-series aluminum alloy sheet for automobile were proportioned according to the following weight percentages, Si 0.06%, Fe 0.15%, Cu 0.05%, Mn 0.35%, Mg 3.2%, Cr 0.16%, the rest being Al and other inevitable impurities, and then the aluminum alloy raw materials after proportioning were placed in a melting furnace for melting, after slagging, degassing and filtering treatment, casting was performed to obtain aluminum alloy ingots;

[0074] (2) Homogenization: the aluminum alloy ingots were placed in a homogenizing furnace for homogenization treatment, the homogenization temperature was 520°C, and the homogenization time was 8h;

[0075] (3) Rolling: the aluminum alloy ingots after homogenization treatment were directly hot-rolled, the hot rolling process was 1+5 hot rolling, that is, after one hot rough rolling, five continuous rolling was performed, the hot rolling coiling temperature was 320°C, and the coiling thickness was 5mm, then the hot-rolled sheet was subjected to multi-pass cold rolling treatment, the cold rolling reduction was 67%, the cold-rolled sheet was obtained, and the sheet thickness was 1.65mm;

[0076] (4) Annealing: the cold-rolled sheet was annealed in a continuous annealing line, the annealing temperature was 500°C, and the line speed was 36m / min, to obtain the 5-series aluminum alloy sheet in the annealed state.

[0077] Comparative Example 5

[0078] A 5-series aluminum alloy sheet for automobile was prepared in the following steps:

[0079] (1) Melting and casting: the raw materials for preparing the 5-series aluminum alloy sheet for automobile were proportioned according to the following weight percentages, Si 0.06%, Fe 0.15%, Cu 0.05%, Mn 0.35%, Mg 3.2%, Cr 0.16%, the rest being Al and other inevitable impurities, and then the aluminum alloy raw materials after proportioning were placed in a melting furnace for melting, after slagging, degassing and filtering treatment, casting was performed to obtain aluminum alloy ingots;

[0080] (2) Homogenization: the aluminum alloy ingots were placed in a homogenizing furnace for homogenization treatment, the homogenization temperature was 520°C, and the homogenization time was 8h;

[0081] (3) Rolling: the aluminum alloy ingots after homogenization treatment were directly hot-rolled, the hot rolling process was 1+5 hot rolling, that is, after one hot rough rolling, five continuous rolling was performed, the hot rolling coiling temperature was 320°C, and the coiling thickness was 5mm, then the hot-rolled sheet was subjected to multi-pass cold rolling treatment, the cold rolling reduction was 67%, the cold-rolled sheet was obtained, and the sheet thickness was 1.65mm;

[0082] (4) annealing: the cold-rolled plate is annealed by a continuous annealing line, the annealing temperature is 500℃, and the line speed is 36m / min, to obtain the annealed 5-series aluminum alloy plate;

[0083] (5) surface treatment: the annealed 5-series aluminum alloy plate is sequentially subjected to alkali washing and acid washing, the alkali washing solution is sodium hydroxide and potassium hydroxide, the pH value is 10.5, the alkali washing temperature is 68℃, and the line speed is 32m / min; the acid washing solution is sulfuric acid and hydrofluoric acid, and the volume ratio of sulfuric acid to hydrofluoric acid in the acid washing solution is 6:1, the pH value is 4.5, the acid washing temperature is 66℃, and the line speed is 32m / min, to obtain the 5-series aluminum alloy plate for automobiles with high adhesive performance.

[0084] In the alkali washing and acid washing processes of the above examples 1-3 and comparative examples 1-5, the alkali washing and acid washing are carried out by spraying, and the spraying flow rates are controlled to be 10L / min·m 2 , 12L / min·m 2 , respectively.

[0085] The oxide film thicknesses (the oxide film thicknesses are measured by X-ray diffraction method, and the oxide film thicknesses are calculated by measuring diffraction angles and diffraction peak intensities), surface roughnesses, and adhesive samples (two-component adhesives are used) of the above examples 1-3 and comparative examples 1-5 are detected, as shown in Table 1 below.

[0086] Table 1: Performance detection results of examples 1-3 and comparative examples 1-5

[0087]

[0088]

[0089] The detection results in the above Table 1 are analyzed as follows:

[0090] The thickness of the oxidation film prepared by the plate material in embodiments 1-3 can be completely removed after surface treatment (alkali washing, acid washing), and because there is no excessive cleaning, the surface activity of the plate material is poor, and the generated oxidation film is relatively slow. In addition, by using appropriate alkali washing and acid washing in embodiments 1-3, the surface roughness can be improved, which is beneficial to improve the adhesion between the plate and the glue, and further improve the adhesive property. In comparative example 1, because the Mg content is high, the plate is easy to generate a thick oxidation film in the environment, and it is not easy to clean, which affects the adhesion between the glue layer and the plate surface. In comparative example 2, because the Fe and Mn element content is high, it is easy to cause the size of Al6(FeMn) phase to be large and the distribution to be uneven, and then the oxidation film layer is unevenly distributed, so that the thick oxidation film position may not be completely cleaned during cleaning, thereby affecting the adhesion between the glue layer and the plate surface. In comparative example 3, because the annealing temperature is high and the annealing line speed is low, the plate surface generates a thick oxidation film, which is not easy to clean during alkali washing and acid washing, and affects the adhesion between the glue layer and the plate surface. In comparative example 5, because the alkali washing and acid washing temperature is high and the line speed is low, excessive surface cleaning occurs, which can cause the active aluminum matrix on the plate surface to be exposed, accelerate the oxidation of the plate surface to generate a porous hydrated film, and affect the adhesive shear strength.

[0091] It should be noted that the parts not mentioned in the present application can be realized by using or referring to the existing technology.

[0092] Of course, the above description is not a limitation of the present application, and the present application is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present application should also be within the scope of the present application.

Claims

1. A method for producing a 5-series aluminum alloy sheet for automobiles having high adhesion properties, characterized by, The method comprises the following steps: (1) smelting and casting: raw materials for preparing 5-series aluminum alloy sheet for automobile are proportioned according to the following weight percentage: Si 0.04-0.08%, Fe 0.10-0.20%, Cu 0.02-0.08%, Mn 0.30-0.40%, Mg 2.8-3.2%, Cr 0.15-0.25%, and the rest is Al and other inevitable impurities, then the aluminum alloy raw materials after proportioning are placed in a smelting furnace for smelting, and after slagging, degassing and filtering, casting is carried out to obtain aluminum alloy ingot; (2) homogenization: the aluminum alloy ingot is placed in a homogenization furnace for homogenization treatment; (3) rolling: the aluminum alloy ingot after homogenization is first hot-rolled, the hot-rolled coiling temperature is 320-350℃, and the coiling thickness is 5-7mm, then the hot-rolled sheet is cold-rolled to obtain a cold-rolled sheet; (4) annealing: the cold-rolled sheet is annealed in a continuous annealing line to obtain a 5-series aluminum alloy sheet in annealed state; (5) surface treatment: the 5-series aluminum alloy sheet in annealed state is sequentially subjected to alkali washing and acid washing to obtain a 5-series aluminum alloy sheet for automobile with high adhesive property.

2. The method of producing a 5-series aluminum alloy sheet for automobiles having high adhesion according to claim 1, characterized in that, In the step (2), the homogenization temperature is 510-530℃, and the homogenization time is 6-10h.

3. The method of producing a 5-series aluminum alloy sheet for automobiles having high adhesive properties according to claim 1, characterized in that, In the step (3), the hot rolling process is 1+5 hot rolling, that is, after hot rough rolling, five continuous rolling is carried out.

4. The method of producing a 5-series aluminum alloy sheet for automobiles having high adhesive properties according to claim 1, characterized in that, In the step (3), the cold rolling reduction ratio during cold rolling is 60%-70%.

5. The method of producing a 5-series aluminum alloy sheet for automobiles having high adhesive properties according to claim 1, characterized in that, In the step (4), the annealing temperature is 480-500℃, and the linear speed is 35-40m / min.

6. The method of producing a 5-series aluminum alloy sheet for automobiles having high adhesive properties according to claim 1, characterized in that, In the step (5), the alkali washing solution is a mixed solution of sodium hydroxide and potassium hydroxide, and the pH value is 10.5-11.5; the acid washing solution is a mixed solution of sulfuric acid and hydrofluoric acid, and the pH value is 4.0-4.5, and in the acid washing solution, the volume ratio of sulfuric acid to hydrofluoric acid is 5-7:

1.

7. The method of producing a 5-series aluminum alloy sheet for automobiles having high adhesion according to claim 6, wherein In the step (5), the alkali washing temperature is 50-65℃, and the linear speed is 35-45m / min; the acid washing temperature is 50-65℃, and the linear speed is 35-45m / min.

8. The method of producing a 5-series aluminum alloy sheet for automobiles having high adhesive properties according to claim 1, characterized in that, The 5-series aluminum alloy sheet for automobile with high adhesive property obtained in the step (4) has an oxide film thickness of not more than 500nm.

9. The method of producing a 5-series aluminum alloy sheet for automobiles having high adhesive properties according to claim 1, wherein The 5-series aluminum alloy sheet for automobile with high adhesive property obtained in the step (5) has a surface roughness of 0.4-0.52μm.

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