Preparation method of green low-carbon 7000 series aluminum plate strip for consumer electronics

Abstract

The invention relates to a preparation method of a green low-carbon 7000 series aluminum plate strip for consumer electronics. The preparation method comprises the steps of semi-continuous casting, homogenizing heat treatment, saw cutting, surface milling, preheating, hot rolling, cold rolling, solid solution quenching, aging treatment and the like. According to the method, processes such as high-temperature short-time solid solution-step quenching-on-line pre-stretching are accurately matched and integrated through a green regenerative large-specification semi-continuous casting and rapid homogenizing technology, the residual internal stress of the strip is reduced while it is ensured that a supersaturated solid solution is formed, the aging temperature rise rate and the heat preservation system are controlled, and the heat preservation performance of the strip is improved. Precise regulation and control on the size and distribution of the precipitated phase and no precipitation zone on the grain boundary are achieved, the cooperative control problem of high recovery, high strength and high plane is synchronously solved, and excellent comprehensive performance is obtained. The method is easy to operate, is suitable for industrial large-scale production, and conforms to the green and low-carbon development requirements of consumer electronics.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of aluminum alloy processing, and in particular to a preparation method of green low-carbon 7000-series aluminum plate strip for consumer electronics. BACKGROUND

[0002] 7000-series aluminum alloys have the advantages of light weight, resistance to external impact and good heat conductivity, and 3C electronic products such as smart phones, smart wearable devices, television frames and tablet computers have gradually adopted 7000-series high-strength aluminum alloys. At the same time, brand manufacturers have proposed green development requirements of high-proportion recycled aluminum and industrial needs of wide and large specifications and high utilization rate. With the addition of high-proportion recycled aluminum, impurity elements such as Fe and Si increase, and hard second phases bring risks of extrusion and stamping cracking of finished products. In addition, large-scale casting increases the difference between the surface and the core in the solidification and crystallization speed, aggravates the composition and organizational segregation, increases the internal stress, and the primary phase of the ingot is also coarsened. How to overcome the adverse effects of high recycling proportion, large-scale ingot, quenching sensitivity and other adverse effects, and coordinate key preparation technologies such as casting parameters, deformation rolling, solid solution quenching and artificial aging to meet the final service performance of the product.

[0003] Patent No. 201810533142.2 discloses a 7xxx-series aluminum alloy plate and a preparation process thereof, which limits trace elements such as Fe≤0.1%, Si≤0.06% and Mn≤0.01%, and adopts high-temperature homogenization at 450-500 DEG C and high-temperature preheating process at 420-500 DEG C. The purpose is to obtain good anodic oxidation surface quality, but high-proportion recycled aluminum cannot be added.

[0004] Patent No. 202111284311.1 discloses an Al-Zn-Mg-Cu alloy resistant to stress corrosion and a preparation method thereof. By adjusting the content and ratio of Zn, Mg and Cu elements, adding appropriate rare earth element Y and reinforcing particles, and adopting three-stage complex homogenization treatment at 380-430 DEG C for 6-10 hours, 450-468 DEG C for 5-8 hours and 470-480 DEG C for 20-40 hours, the aluminum alloy has high strength and good corrosion resistance. The rare earth element Y and the reinforcing particles increase the production cost and the control difficulty.

[0005] Patent with application number 202110668036.7 discloses an aviation high damage tolerance 7 series aluminum alloy thick plate and its preparation method. It controls Fe≤0.08%, Si≤0.07%, Mn≤0.06% and other elements through ultra-high purification, adopts multi-stage homogenization to eliminate large-size ingot segregation and residual second phase content, and further obtains substructure organization state through large reduction ratio multi-stage hot rolling process, thereby improving the damage tolerance of the aluminum alloy thick plate. However, the ultra-high purification technology route limits the raw material source to some extent and increases the production cost, and the hot rolling final rolling temperature ≥ 350℃ is easy to cause coarse second phase precipitation after cooling, and the method cannot add high proportion of recycled aluminum.

[0006] Patent with application number 202011322585.0 discloses a high damage tolerance low quench sensitivity 7 series aluminum alloy thick plate production process. It also controls Fe≤0.08%, Si≤0.05%, Mn≤0.06% and other harmful elements through ultra-high purification, and adopts double-stage solid solution and double-stage aging to improve the strength, fracture toughness and corrosion resistance of the finished product, but the hot rolling final rolling temperature is 430±20℃, which is easy to cause a large amount of coarse second phase to precipitate after hot rolling cooling, and the method cannot add high proportion of recycled aluminum. SUMMARY

[0007] Therefore, the purpose of the present application is to provide a green low-carbon 7000 series aluminum plate strip preparation method for consumer electronics, which is easy to operate, reduces the residual internal stress of the aluminum plate strip, and obtains excellent comprehensive performance, thereby synchronously solving the problems of high recycling proportion, high strength and high plane coordination control.

[0008] The present application adopts the following scheme: a green low-carbon 7000 series aluminum plate strip preparation method for consumer electronics, comprising the following steps: (1) Semi-continuous casting: according to the alloy composition ratio, the recycled aluminum and the intermediate alloy or additive are heated and melted, then heat preservation and online degassing are carried out, and after plate filtration and deslagging, the ingot is obtained by casting; (2) Homogenization treatment: the ingot is quickly transferred to the homogenization furnace for homogenization heat treatment within 2h after the casting of the ingot is completed, and then air cooling is carried out after the furnace is discharged; (3) Sawing and milling: the ingot is sawed and milled to obtain a flat ingot; (4) Preheating: the flat ingot is heated to 420-440℃ and kept for 1-4 hours; (5) Hot rolling: the flat ingot is hot rolled to obtain a hot rolled coil with a thickness of 4.0-8.0mm; (6) Cold rolling: the hot rolled coil is cold rolled to a finished product thickness of 2.0-4.0mm to obtain a cold rolled coil; (7) solution quenching: the cold-rolled coil is subjected to solution quenching and on-line pre-stretching treatment by using a gas cushion type continuous annealing furnace to obtain a quenched coil; (8) aging treatment: the quenched coil is subjected to artificial aging treatment to finally obtain a green low-carbon 7000 series aluminum plate strip for consumer electronics.

[0009] Further, in step (1), the casting crystallizer thickness is 400-500 mm, the casting temperature is 670-675℃, the casting water flow is 60-70 m3 / h, and the casting water temperature is 20-30℃.

[0010] Further, the composition of the cast ingot obtained in step (1) is as follows in terms of mass percentage: Si 0.10-0.25%, Fe 0.20-0.45%, Cu 2.0-4.0%, Mg 3.00%-4.00%, Zn 6.0%-8.0%, and the balance of Al and impurities, with the proportion of recycled aluminum added being ≥60%.

[0011] Further, in step (2), the average cooling rate V1 of the fan forced cooling is 30-50℃ / h.

[0012] Further, in step (6), the cold rolling processing rate is 50-80%, the cold rolling is performed in 3-5 passes, the single pass reduction rate is ≤30%, the final pass reduction rate is ≤20%, and the temperature after all cold rolling passes is <150℃.

[0013] Further, in step (7), the solution quenching treatment is as follows: solution treatment at a heating rate of 2-5℃ / sec to 475-480℃ / 60-240 sec, and quenching treatment by transferring in <10 sec, first with 1.0-2.0 bar hard water quenching, then with 0.5-1.0 bar soft water quenching, and finally air cooling to room temperature.

[0014] Further, in step (8), the artificial aging treatment is as follows: aging temperature 120-130℃, holding time 24-48 h, and the temperature rise rate V2 to the aging temperature is controlled to be 3-10℃ / h.

[0015] The final aluminum alloy product has a thickness of 2-4 mm, a tensile strength ≥520 MPa, a yield strength ≥480 MPa, an elongation ≥12%, an electrical conductivity ≥32% IACS, and a maximum second phase size <25 μm.

[0016] Compared with the prior art, the present application has the following beneficial effects: the present application is easy to operate, suitable for industrial large-scale production, and meets the development needs of green and low-carbon consumer electronics; through large-scale semi-continuous casting and rapid homogenization technology, the high-temperature short-time solid solution-staged quenching (hard water quenching-soft water quenching-air quenching)-online pre-stretching process is accurately matched and integrated, which not only ensures the formation of supersaturated solid solution, but also significantly reduces the residual internal stress of the aluminum plate strip, and through the control of the aging heating rate and the holding system, the size, distribution and grain boundary precipitate-free zone of the precipitated phase are precisely controlled, and the problems of high recovery rate, high strength and high plane are simultaneously solved, and excellent comprehensive performance is obtained.

[0017] In order to make the purpose, technical scheme and advantages of the present application more clear and obvious, the following will be further described in detail through specific examples and related drawings. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The second phase optical microscope (OM) comparison chart of the ingot obtained after the homogenization heat treatment of the example 1 (A) and the comparative example 1 (B) at different cooling rates; Figure 2 The shaping cracking comparison chart of the example 1 and the comparative example 1 at different cooling rates after the homogenization heat treatment; Figure 3 The intracrystalline precipitated phase transmission electron microscope (SEM) comparison chart of the finished product obtained by the example 2 (A) and the comparative example 2 (B) at different artificial aging heating rates; DETAILED DESCRIPTION

[0019] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application pertains.

[0020] It should be noted that the terms used herein are only for the purpose of describing the 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 intended to include the plural form, and in addition, it should be understood that when the terms "comprise" and / or "include" are used in the specification, they indicate the presence of a feature, step, operation, device, component and / or combination thereof.

[0021] A green and low-carbon 7000 series aluminum plate strip preparation method for consumer electronics, characterized in that it comprises the following steps: (1) Semi-continuous casting: according to the alloy composition ratio, the recycled aluminum and the intermediate alloy or the additive are heated and melted, the recycled aluminum addition ratio is ≥ 60%, then the heat preservation and on-line degassing are carried out, the plate filter is used for slag removal, then the casting is carried out, the casting crystallizer thickness is 400-500 mm, the casting temperature is 670-675 ℃, the casting water flow is 60 m3 / h-70 m3 / h, and the casting water temperature is 20-30 ℃; a cast ingot is obtained, and the composition of the cast ingot is as follows in percentage by mass: Si 0.10-0.25%, Fe 0.20-0.45%, Cu 2.0-4.0%, Mg 3.00%-4.00%, Zn 6.0%-8.0%, and the rest is Al and impurities; (2) Homogenization treatment: the cast ingot is quickly transferred to a homogenization furnace for homogenization heat treatment within 2 hours after the end of casting, and then is subjected to forced air cooling after being discharged from the furnace, and the average cooling rate V1 of forced air cooling is 30 ℃ / h≤V1≤50 ℃ / h; (3) Sawing and milling: the cast ingot is sawed and milled to obtain a flat ingot; (4) Preheating: the flat ingot is heated to 420-440 ℃ and is kept for 1-4 hours; (5) Hot rolling: the flat ingot is subjected to hot rolling to obtain a hot-rolled coil with a thickness of 4.0-8.0 mm; (6) Cold rolling: the hot-rolled coil is cold-rolled to a finished product thickness of 2.0-4.0 mm, the cold rolling processing rate is 50%-80%, the cold rolling is carried out in 3-5 passes, the single-pass reduction rate of cold rolling is ≤30%, the last-pass reduction rate of cold rolling is ≤20%, the temperature after rolling in all cold rolling passes is <150 ℃, and a cold-rolled coil is obtained; (7) Solution quenching: the cold-rolled coil is subjected to solution quenching and on-line pre-stretching treatment by using a gas cushion type continuous annealing furnace, and a quenched coil is obtained; the solution quenching treatment is as follows: the solution treatment is carried out at a temperature increasing rate of 2-5 ℃ / sec to 475-480 ℃ for 60-240 sec, then the coil is transferred to a quenching treatment at a transfer time of <10 sec, the quenching treatment is carried out by first opening 1.0-2.0 bar hard water quenching, then opening 0.5-1.0 bar soft water quenching, and finally air cooling to room temperature; (8) Aging treatment: the quenched coil is subjected to artificial aging treatment at an aging temperature of 120-130 ℃ and a holding time of 24-48 h, the temperature increasing rate V2 from room temperature to the aging temperature is controlled to be 3 ℃ / h≤V2≤10 ℃ / h, and finally a finished product, a green low-carbon 7000 series aluminum plate strip for consumer electronics, is obtained.

[0022] The final obtained aluminum alloy finished product has a thickness of 2-4 mm, a tensile strength of ≥520 MPa, a yield strength of ≥480 MPa, an elongation of ≥12%, an electrical conductivity of ≥32% IACS, and a maximum size of second phase of <25 μm.

[0023] The application precisely matches and integrates high-temperature short-time solid solution, grading quenching (hard water quenching-soft water quenching-air quenching), online pre-stretching and other processes through large-scale semi-continuous casting and rapid homogenization technology, significantly reduces the residual internal stress of the aluminum plate strip while ensuring the formation of a supersaturated solid solution, realizes precise regulation and control of the size, distribution and grain boundary non-deposition zone of precipitated phases by controlling the aging temperature rising rate and holding system, and simultaneously solves the problems of high recovery rate, high strength and high plane synergistic control, thereby obtaining excellent comprehensive performance.

[0024] The application will be further described below in combination with examples and comparative examples.

[0025] Example One A preparation method of a green low-carbon 7000 series aluminum plate strip for consumer electronics, comprising the following steps: (1) Semi-continuous casting: according to the alloy composition ratio, heat and melt the recycled aluminum and intermediate alloy or additive, the recycled aluminum addition ratio is 65%, then perform heat preservation and online degassing, perform casting after using a plate filter to remove slag, the casting crystallizer thickness is 500 mm, the casting temperature is 670 ℃, the casting water flow is 65 m3 / h, and the casting water temperature is 20 ℃; a cast ingot is obtained, and the composition of the cast ingot is as follows in terms of mass percentage: Si 0.12%, Fe 0.25%, Cu 2.45%, Mg 3.25%, Zn 6.67%, and the remainder is Al and other impurities; (2) Homogenization treatment: the cast ingot is rapidly transferred to a homogenization furnace for homogenization heat treatment within 1 h after the end of casting, and is subjected to forced air cooling after being discharged from the furnace, and the average cooling rate V1 of forced air cooling is 32 ℃ / h; (3) Sawing and milling: the cast ingot is sawed and milled to obtain a flat ingot; (4) Preheating: the flat ingot is heated to 430 ℃ and is kept for 3 h; (5) Hot rolling: the flat ingot is hot rolled to obtain a hot-rolled coil with a thickness of 4.5 mm; (6) Cold rolling: the hot-rolled coil is cold rolled to a finished product thickness of 2.0 mm, the cold rolling processing rate is 55.56%, and the cold rolling pass distribution is 4.5-3.2-2.4-2.0, a total of 3 passes, and the single-pass reduction rates are 28.89%, 25% and 16.67% respectively, and the rolling temperature after all the cold rolling passes is 138 ℃, thereby obtaining a cold-rolled coil; (7) Solution quenching: the cold-rolled coil is subjected to solution quenching and online pre-stretching treatment by using an air cushion type continuous annealing furnace, thereby obtaining a quenched coil; the solution quenching treatment is as follows: solid solution treatment is performed at a temperature rising rate of 3 ℃ / sec to 475 ℃ / 120 sec, then quenching treatment is performed by using a transfer time of 5.0 sec, the quenching treatment is first performed by using 1.0 bar hard water quenching, then 0.5 bar soft water quenching, and finally air cooling to room temperature; (8) aging treatment: the quenched coil is subjected to artificial aging treatment, the aging temperature is 120℃, the holding time is 24h, the temperature rising rate V2=6℃ / h from room temperature to the aging temperature is controlled, and finally the green low-carbon 7000 series aluminum plate strip for consumer electronics is prepared.

[0026] The green low-carbon 7000 series aluminum plate strip for consumer electronics is finally prepared, the thickness of the finished product is 2.0mm, the tensile strength is 535MPa, the yield strength is 488MPa, the elongation is 14.56%, the electrical conductivity is 33.89%IACS, and the maximum size of the second phase is 23.43μm.

[0027] Example two: A preparation method of a green low-carbon 7000 series aluminum plate strip for consumer electronics comprises the following steps: (1) semi-continuous casting: according to the alloy composition ratio, recycled aluminum and intermediate alloy or additives are heated and melted, the recycled aluminum is added at a proportion of 80%, and then heat preservation and online degassing are performed, and after the plate filter is used for slag removal, casting is performed, the casting crystallizer thickness is 480mm, the casting temperature is 673℃, the casting water flow is 65m3 / h, and the casting water temperature is 20℃; a cast ingot is obtained, and the composition of the cast ingot is as follows in terms of mass percentage: Si 0.17%, Fe 0.32%, Cu 3.2%, Mg 3.56%, Zn 7.34%, and the balance of Al and other impurities; (2) homogenization treatment: the cast ingot is quickly transferred to a homogenization furnace for homogenization heat treatment within 2h after the casting is completed, and after being discharged, the fan forced cooling is used, and the average cooling rate V1=45℃ / h; (3) sawing and milling: the cast ingot is sawed and milled to obtain a flat ingot; (4) preheating: the flat ingot is heated to 420℃ and kept for 4h; (5) hot rolling: the flat ingot is hot rolled to obtain a hot-rolled coil with a thickness of 6.0mm; (6) cold rolling: the hot-rolled coil is cold rolled to a finished product thickness of 2.5mm, the cold rolling processing rate is 58.33%, the cold rolling pass distribution is 6.0-4.25-3.1-2.5 for a total of 3 passes, the cold rolling pass reduction rates are 29.17%, 27.06% and 19.35% respectively, and the cold rolling pass temperature after rolling is 143℃, and a cold-rolled coil is obtained; (7) solution quenching: the cold-rolled coil is subjected to solution, quenching and online pre-stretching treatment by using a gas cushion type continuous annealing furnace, and a quenched coil is obtained; the solution, quenching treatment is as follows: the solution treatment is performed at a temperature rising rate of 4.5℃ / sec to 478℃ / 180sec, then the transfer time is 7sec to quenching treatment, the quenching treatment is first opened to 1.5bar hard water quenching, then opened to 0.7bar soft water quenching, and finally air cooled to room temperature; (8) aging treatment: the quenched coil is subjected to artificial aging treatment, the aging temperature is 125℃, the holding time is 32h, the temperature rising rate V2=4℃ / h from room temperature to aging is controlled, and finally the green low-carbon 7000 series aluminum plate strip for consumer electronics is prepared.

[0028] The green low-carbon 7000 series aluminum plate strip for consumer electronics is finally prepared, the thickness of the finished product is 2.5mm, the tensile strength is 556MPa, the yield strength is 524MPa, the elongation is 13.87%, the electrical conductivity is 32.87%IACS, and the maximum size of the second phase is 22.54μm.

[0029] Example Three A preparation method of a green low-carbon 7000 series aluminum plate strip for consumer electronics comprises the following steps: (1) semi-continuous casting: according to the alloy composition ratio, the recycled aluminum and intermediate alloy or additive are heated and melted, the recycled aluminum is added at a proportion of 90%, and then heat preservation and online degassing are performed, and after the plate filter is used for slag removal, casting is performed, the casting crystallizer thickness is 420mm, the casting temperature is 675℃, the casting water flow is 60m3 / h, and the casting water temperature is 21℃; a cast ingot is obtained, and the composition of the cast ingot is as follows in terms of mass percentage: Si 0.23%, Fe 0.42%, Cu 2.24%, Mg 3.53%, Zn 6.98%, and the balance of Al and other impurities; (2) homogenization treatment: the cast ingot is quickly transferred to a homogenization furnace for homogenization heat treatment within 2h after the casting is completed, and after being discharged, the fan forced cooling is used, and the average cooling rate V1=40℃ / h; (3) sawing and milling: the cast ingot is sawed and milled to obtain a flat ingot; (4) preheating: the flat ingot is heated to 440℃ and kept for 1h; (5) hot rolling: the flat ingot is hot rolled to obtain a hot-rolled coil with a thickness of 8.0mm; (6) cold rolling: the hot-rolled coil is cold rolled to a finished product thickness of 3.0mm, the cold rolling processing rate is 62.5%, the cold rolling pass distribution is 8.0-5.8-4.4-3.5-3.0, a total of 4 passes, and the cold rolling pass reduction rates are 27.5%, 24.14%, 20.45% and 14.29% respectively, the cold rolling pass temperature after rolling is 124℃, and a cold-rolled coil is obtained; (7) solid solution quenching: the cold-rolled coil is subjected to solid solution, quenching and online pre-stretching treatment by using an air cushion type continuous annealing furnace, and a quenched coil is obtained; the solid solution, quenching treatment is as follows: the solid solution treatment is performed at a temperature rising rate of 5℃ / sec to 480℃ / 220sec, then the transfer time is 3sec to quenching treatment, the quenching treatment is first quenched by opening 2.0bar hard water, then quenched by opening 0.8bar soft water, and finally air cooled to room temperature; (8) aging treatment: the quenched coil is subjected to artificial aging treatment, the aging temperature is 130℃, the holding time is 24h, the temperature rising rate V2 from room temperature to aging is 5.6℃ / h, and finally the green low-carbon 7000 series aluminum plate strip for consumer electronics is prepared.

[0030] The green low-carbon 7000 series aluminum plate strip for consumer electronics is finally prepared, the thickness of the finished product is 3.0mm, the tensile strength is 559MPa, the yield strength is 523MPa, the elongation is 13.59%, the electrical conductivity is 32.89%IACS, and the maximum size of the second phase is 22.31μm.

[0031] Comparative Example 1 After the homogenization heat treatment furnace is discharged, natural cooling is adopted, the average cooling rate V1 is 25℃ / h, and the rest of the operations are the same as in Example 1.

[0032] The results show that after the ingot is homogenized, the cooling speed is slow, a large amount of second phase is precipitated and coarsened, and the full redissolution at high temperature and short time of the continuous retort line cannot be achieved, so that the final product is finally inherited (such as Figure 1 ), and finally the shaping cracking occurs in the application end of the product (such as Figure 2 ).

[0033] Comparative Example 2 In step (8), the temperature rising rate V2 from room temperature to aging is 12℃ / h, and the rest of the operations are the same as in Example 2.

[0034] The results show that due to the too fast artificial aging temperature rising rate, the intracrystalline η phase is coarsened, the tensile strength of the finished product is 545MPa, the yield strength is 512MPa, the elongation is 10.38%, the strength and plasticity performance is obviously reduced, and finally the shaping cracking occurs in the application end of the product (such as Figure 3 ).

[0035] The above is only a preferred embodiment of the present application, and is not intended to limit the present application in other forms. Any person skilled in the art can modify or change the above disclosed technical content to obtain equivalent embodiments. However, any simple modification, equivalent change and modification made on the basis of the technical essence of the present application to the above embodiments still belongs to the protection scope of the present application.

Claims

1. A method for preparing green, low-carbon 7000 series aluminum sheet and strip for consumer electronics, characterized in that: The method comprises the following steps: (1) Semi-continuous casting: according to the alloy component ratio, the recycled aluminum is heated and melted with the intermediate alloy or additive, and then is subjected to heat preservation and on-line degassing, and is subjected to casting after deslagging by using a plate filter to obtain a cast ingot; (2) Homogenization treatment: the cast ingot is quickly transferred to a homogenization furnace within 2 hours after the end of casting to be subjected to homogenization heat treatment, and is subjected to forced air cooling after being discharged from the furnace; (3) Sawing and milling: the cast ingot is subjected to sawing and milling to obtain a flat ingot; (4) Preheating: the flat ingot is heated to 420-440 DEG C and is kept for 1-4 hours; (5) Hot rolling: the flat ingot is subjected to hot rolling to obtain a hot-rolled coil with a thickness of 4.0-8.0 mm; (6) Cold rolling: the hot-rolled coil is subjected to cold rolling to a finished product thickness of 2.0-4.0 mm to obtain a cold-rolled coil; (7) Solution quenching: the cold-rolled coil is subjected to solution quenching and on-line pre-stretching treatment by using an air cushion type continuous annealing furnace to obtain a quenched coil; (8) Aging treatment: the quenched coil is subjected to artificial aging treatment to finally obtain a finished product of green low-carbon 7000 series aluminum plate strip for consumer electronics.

2. The method for preparing green low-carbon 7000-series aluminum strip for consumer electronics according to claim 1, characterized in that: In step (1), the casting crystallizer has a thickness of 400-500 mm, the casting temperature is 670-675 DEG C, the casting water flow rate is 60-70 m3 / h, and the casting water temperature is 20-30 DEG C.

3. The method for preparing green low-carbon 7000-series aluminum strip for consumer electronics according to claim 1, characterized in that: The cast ingot obtained in step (1) has the following components in terms of mass percentage: Si 0.10-0.25%, Fe 0.20-0.45%, Cu 2.0-4.0%, Mg 3.00%-4.00%, Zn 6.0%-8.0%, and the rest is Al and impurities, and the recycled aluminum is added in a proportion of greater than or equal to 60%.

4. The method for preparing green low-carbon 7000-series aluminum strip for consumer electronics according to claim 1, characterized in that: In step (2), the forced air cooling has an average cooling rate V1 of 30-50 DEG C / h.

5. The method for preparing green low-carbon 7000-series aluminum strip for consumer electronics according to claim 1, characterized in that: In step (6), the cold rolling has a processing rate of 50-80%, is performed for 3-5 passes, has a single-pass reduction rate of less than or equal to 30%, has a final-pass reduction rate of less than or equal to 20%, and has a post-rolling temperature of less than 150 DEG C.

6. The method for preparing green low-carbon 7000-series aluminum strip for consumer electronics according to claim 1, characterized in that: In step (7), the solution quenching treatment is specifically as follows: the temperature is raised at a rate of 2-5 DEG C / sec to 475-480 DEG C for 60-240 sec, then is transferred to the quenching treatment in less than 10 sec, the quenching treatment is first performed by using 1.0-2.0 bar hard water, then is performed by using 0.5-1.0 bar soft water, and finally is air-cooled to room temperature.

7. The method for preparing green low-carbon 7000-series aluminum strip for consumer electronics according to claim 1, characterized in that: In step (8), the artificial aging treatment is specifically as follows: the aging temperature is 120-130 DEG C, the aging time is 24-48 h, the temperature is controlled to rise at a rate V2 of 3-10 DEG C / h to the aging temperature.

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