A method for improving corrosion resistance of an aluminum-zinc-magnesium-copper alloy

Abstract

The present application relates to a kind of methods for improving the corrosion resistance of aluminum-zinc-magnesium-copper alloy, the aluminum-zinc-magnesium-copper alloy includes Cu:1.2~2.0%, Mg:2.1~2.9%, Zn:5.1~6.1%, Cr:0.18~0.28%, Si≤0.4%, Fe≤0.5%, Mn≤0.3%, Ti≤0.2%, the rest is Al and inevitable impurities.By rolling and heat treatment to the aluminum-zinc-magnesium-copper alloy to enhance its corrosion resistance, the present application relates to non-ferrous metal technical field.The method for improving the corrosion resistance of aluminum-zinc-magnesium-copper alloy, the preparation process is simple, using rolling and solid solution, and the method of double back to aging T6 heat treatment, the instrument used is common rolling mill, muffle furnace, electrochemical workstation, ultrasonic wave, polishing machine etc., the corrosion resistance of the material obtained is greatly improved compared with the aluminum-zinc-magnesium-copper alloy only after T6 heat treatment.

Description

TECHNICAL FIELD

[0001] The application relates to a method for improving the corrosion resistance of an aluminum-zinc-magnesium-copper alloy and belongs to the technical field of non-ferrous metals. BACKGROUND

[0002] The aluminum-zinc-magnesium-copper alloy is widely applied to the fields of precision instruments, aerospace and medicine due to excellent mechanical properties, but in addition to the excellent mechanical properties, the aluminum-zinc-magnesium-copper alloy material is required to have excellent corrosion resistance in many scenes. For example, in a marine atmospheric environment containing sea salt particles, the aluminum-zinc-magnesium-copper alloy parts are prone to pitting corrosion and intergranular corrosion, which is relatively harmful, can weaken the binding force between the grains, cause the mechanical strength of the material to disappear, and thus cause the material to have corrosion cracks and other phenomena, leading to sudden fracture of the parts and causing unpredictable accidents.

[0003] The aluminum-zinc-magnesium-copper alloy is a heat-treatable strengthening aluminum alloy, and the comprehensive performance thereof can be improved based on aging strengthening. The size of precipitated phases and the distribution of microstructure structures in the alloy can be changed through different heat treatment processes, so that the aluminum alloy with required performance is obtained. Therefore, controlling the size of precipitated strengthening phases in the alloy through rolling and optimizing the heat treatment process is an effective way to improve the corrosion resistance of the aluminum-zinc-magnesium-copper alloy. SUMMARY

[0004] In order to solve the problem that the existing aluminum-magnesium-zinc-copper alloy has low corrosion resistance, the application provides a method for improving the corrosion resistance of an aluminum-magnesium-zinc-copper alloy, and the processing steps are as follows:

[0005] (1) Rolling treatment: the aluminum-zinc-magnesium-copper alloy is cold-rolled to obtain a raw material A with a deformation of 5% to 40%.

[0006] (2) Solid solution treatment: the raw material A is uniformly heated to 430 to 450 DEG C at a constant speed, and the raw material B is obtained after heat preservation for 100 to 120 min.

[0007] (3) Quenching treatment: the raw material B is water-quenched to room temperature to obtain a raw material C.

[0008] (4) Pre-aging treatment: the raw material C is uniformly heated to 120 to 130 DEG C at a constant speed, and the raw material D is obtained after heat preservation for 24 to 28 h.

[0009] (5) Double-regression aging treatment: the raw material D is uniformly heated to 160 to 180 DEG C at a constant speed, heat preservation is performed for 15 to 20 min, then the raw material D is uniformly heated to 180 to 200 DEG C at a constant speed, heat preservation is performed for 15 to 20 min, and then the raw material E is obtained after water quenching to room temperature.

[0010] (6) Re-aging treatment: the raw material E is uniformly heated to 120 to 130 DEG C at a constant speed, and the raw material E is obtained after heat preservation for 24 to 28 h.

[0011] Preferably, the aluminum-zinc-magnesium-copper alloy in step (1) contains the following components in mass percentage: Cu: 1.2-2.0%, Mg: 2.1-2.9%, Zn: 5.1-6.1%, Cr: 0.18-0.28%, Si≤0.4%, Fe≤0.5%, Mn≤0.3%, Ti≤0.2%, and the rest are Al and unavoidable impurities, and the total mass percentage of all components is 100%.

[0012] Preferably, the rolling method in step (1) is cold rolling, and the rolling pass is one pass.

[0013] Preferably, the uniform heating rate in steps (2)(4)(5)(6) is 10-15°C / min.

[0014] Beneficial effects of the present invention

[0015] (1) The present invention pre-applies internal stress to the aluminum-zinc-magnesium-copper alloy by cold rolling it with different deformation amounts, so that the second phase particles in the alloy are refined and become dense and continuous; pre-aging treatment is performed to make the state of the alloy reach a peak; double regression peak aging allows the second phase MgZn2 phase to be fully precipitated, and at the same time, the precipitation of the Fe-rich phase is effectively prevented due to the effect of the pre-applied internal stress; and regression aging stabilizes this state.

[0016] (2) The present invention effectively controls the precipitation, size and distribution of the second phase through cold rolling and multi-stage peak aging treatment, so that the alloy has excellent corrosion resistance, and the process flow is simple and convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 These are the polarization curves of the alloy samples obtained in Examples 1 to 4 and Comparative Examples 1 to 5.

[0018] Figure 2 It is a general schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0019] Example 1

[0020] A corrosion-resistant zinc-magnesium-copper alloy is prepared. The test sample is mainly an aluminum-zinc-magnesium-copper alloy, and its main components are Cu: 1.2%, Mg: 2.9%, Zn: 6.1%, Cr: 0.28%, Si=0.3%, Fe=0.5%, Mn=0.3%, Ti=0.2%, and the rest is Al and unavoidable impurities. The steps are as follows:

[0021] (1) Rolling treatment: The aluminum-zinc-magnesium-copper alloy is rolled by cold rolling, with one pass and a deformation of 5% to obtain raw material A.

[0022] (2) Solution treatment: the aluminum zinc magnesium copper alloy is uniformly heated to 430 °C at a heating rate of 15 °C / min, and the holding time is 120 min to obtain raw material B.

[0023] (3) Quenching treatment: the raw material B is water-quenched to room temperature to obtain raw material C.

[0024] (4) Pre-aging treatment: the raw material C is uniformly heated to 120 °C at a heating rate of 15 °C / min, and the holding time is 24 h to obtain raw material D.

[0025] (5) Double peak aging treatment: the raw material D is uniformly heated to 160 °C at a heating rate of 15 °C / min, and the holding time is 15 min, then uniformly heated to 180 °C at a heating rate of 15 °C / min, and the holding time is 15 min, and then water-quenched to room temperature to obtain raw material E.

[0026] (6) Re-aging treatment: the raw material E is uniformly heated to 120 °C at a heating rate of 15 °C / min, and the holding time is 24 h to obtain the corrosion-resistant aluminum zinc magnesium copper alloy.

[0027] Example 2

[0028] A kind of preparation of corrosion-resistant zinc magnesium copper alloy, test sample is mainly aluminum zinc magnesium copper alloy, the composition is mainly a kind of preparation of corrosion-resistant zinc magnesium copper alloy, test sample is mainly aluminum zinc magnesium copper alloy, the composition is mainly Cu:2.0%, Mg:2.1%, Zn:5.5%, Cr:0.20%, Si=0.4%, Fe=0.4%, Mn=0.3%, Ti=0.2%, the rest is Al and inevitable impurities, and its steps are as follows:

[0029] (1) Rolling treatment: the aluminum zinc magnesium copper alloy is rolled, the rolling mode is cold rolling, the pass is once, and the deformation amount is 10% to obtain raw material A.

[0030] (2) Solution treatment: the aluminum zinc magnesium copper alloy is uniformly heated to 430 °C at a heating rate of 15 °C / min, and the holding time is 120 min to obtain raw material B.

[0031] (3) Quenching treatment: the raw material B is water-quenched to room temperature to obtain raw material C.

[0032] (4) Pre-aging treatment: the raw material C is uniformly heated to 120 °C at a heating rate of 15 °C / min, and the holding time is 24 h to obtain raw material D.

[0033] (5) Double peak aging treatment: the raw material D is uniformly heated to 160 °C at a heating rate of 15 °C / min, and the holding time is 15 min, then uniformly heated to 180 °C at a heating rate of 15 °C / min, and the holding time is 15 min, and then water-quenched to room temperature to obtain raw material E.

[0034] (6) Re-aging treatment: uniformly heating the raw material E to 120°C at a heating rate of 15°C / min, and keeping the temperature for 24h to obtain the corrosion-resistant aluminum-zinc-magnesium-copper alloy.

[0035] Example 3

[0036] A kind of preparation of corrosion-resistant zinc magnesium copper alloy, test sample is mainly aluminum-zinc-magnesium-copper alloy, the composition is mainly as follows: Cu: 2.0%, Mg: 2.9%, Zn: 6.1%, Cr: 0.28%, Si=0.1%, Fe=0.2%, Mn=0.2%, Ti=0.2%, the rest is Al and inevitable impurities, and its steps are as follows:

[0037] (1) Rolling treatment: rolling the aluminum-zinc-magnesium-copper alloy, the rolling mode is cold rolling, the pass is once, the deformation is 20%, to obtain the raw material A.

[0038] (2) Solution treatment: uniformly heating the aluminum-zinc-magnesium-copper alloy to 430°C at a heating rate of 15°C / min, and keeping the temperature for 120min to obtain the raw material B.

[0039] (3) Quenching treatment: water quenching the raw material B to room temperature to obtain the raw material C.

[0040] (4) Pre-aging treatment: uniformly heating the raw material C to 120°C at a heating rate of 15°C / min, and keeping the temperature for 24h to obtain the raw material D.

[0041] (5) Double peak aging treatment: uniformly heating the raw material D to 160°C at a heating rate of 15°C / min, and keeping the temperature for 15min, then uniformly heating to 180°C at a heating rate of 15°C / min, and keeping the temperature for 15min, and then water quenching to room temperature to obtain the raw material E.

[0042] (6) Re-aging treatment: uniformly heating the raw material E to 120°C at a heating rate of 15°C / min, and keeping the temperature for 24h to obtain the corrosion-resistant aluminum-zinc-magnesium-copper alloy.

[0043] Example 4

[0044] A kind of preparation of corrosion-resistant zinc magnesium copper alloy, test sample is mainly aluminum-zinc-magnesium-copper alloy, the composition is mainly as follows: Cu: 2.0%, Mg: 2.9%, Zn: 6.1%, Cr: 0.28%, Si=0.1%, Fe=0.2%, Mn=0.2%, Ti=0.2%, the rest is Al and inevitable impurities, and its steps are as follows:

[0045] (1) Rolling treatment: the aluminum-zinc-magnesium-copper alloy is rolled, the rolling mode is cold rolling, the pass is one time, and the deformation amount is 40%, to obtain a raw material A.

[0046] (2) Solution treatment: the aluminum-zinc-magnesium-copper alloy is uniformly heated to 450℃ at a heating rate of 10℃ / min, and the holding time is 100min, to obtain a raw material B.

[0047] (3) Quenching treatment: the raw material B is water-quenched to room temperature to obtain a raw material C.

[0048] (4) Pre-aging treatment: the raw material C is uniformly heated to 130℃ at a heating rate of 10℃ / min, and the holding time is 28h, to obtain a raw material D.

[0049] (5) Double peak aging treatment: the raw material D is uniformly heated to 180℃ at a heating rate of 10℃ / min, and the holding time is 20min, then uniformly heated to 220℃ at a heating rate of 10℃ / min, and the holding time is 20min, and then water-quenched to room temperature to obtain a raw material E.

[0050] (6) Re-aging treatment: the raw material E is uniformly heated to 130℃ at a heating rate of 15℃ / min, and the holding time is 28h, to obtain a corrosion-resistant aluminum-zinc-magnesium-copper alloy.

[0051] Comparative Example 1

[0052] As a comparison, the difference between the present example and Example 1 is that the alloy is not rolled, and the remaining steps and the alloy used are the same as those of Example 1, and the specific steps are as follows:

[0053] (1) Solution treatment: the aluminum-zinc-magnesium-copper alloy is uniformly heated to 430℃ at a heating rate of 15℃ / min, and the holding time is 120min, to obtain a raw material A.

[0054] (3) Quenching treatment: the raw material A is water-quenched to room temperature to obtain a raw material B.

[0055] (4) Pre-aging treatment: the raw material B is uniformly heated to 120℃ at a heating rate of 15℃ / min, and the holding time is 24h, to obtain a raw material C.

[0056] (5) Double peak aging treatment: the raw material C is uniformly heated to 160℃ at a heating rate of 15℃ / min, and the holding time is 15min, then uniformly heated to 180℃ at a heating rate of 15℃ / min, and the holding time is 15min, and then water-quenched to room temperature to obtain a raw material D.

[0057] (6) Re-aging treatment: the raw material E is uniformly heated to 120℃ at a heating rate of 15℃ / min, and the holding time is 24h, to obtain a corrosion-resistant aluminum-zinc-magnesium-copper alloy.

[0058] Comparative Example 2

[0059] For comparison, the difference between this embodiment and embodiment 2 is that double regression peak aging and re-aging treatment are not performed. The remaining steps and the alloy used are the same as those in embodiment 2. The specific steps are as follows:

[0060] (1) Rolling treatment: The aluminum-zinc-magnesium-copper alloy is rolled by cold rolling, with one pass and a deformation of 10% to obtain raw material A.

[0061] (2) Solution treatment: The aluminum-zinc-magnesium-copper alloy was uniformly heated to 430°C at a heating rate of 15°C / min and kept at this temperature for 120 min to obtain raw material B.

[0062] (3) Quenching treatment: Raw material B is water-quenched to room temperature to obtain raw material C.

[0063] (4) Pre-aging treatment: Raw material C is heated to 120°C at a rate of 15°C / min and kept at this temperature for 24 h to obtain a corrosion-resistant aluminum-zinc-magnesium-copper alloy.

[0064] Comparative Example 3

[0065] For comparison, the difference between this embodiment and embodiment 3 is that the double regression peak aging is changed to single regression aging treatment. The remaining steps and the alloy used are the same as those in embodiment 3. The specific steps are as follows:

[0066] (1) Rolling treatment: The aluminum-zinc-magnesium-copper alloy is rolled by cold rolling, with one pass and a deformation of 20% to obtain raw material A.

[0067] (2) Solution treatment: The aluminum-zinc-magnesium-copper alloy was uniformly heated to 430°C at a heating rate of 15°C / min and kept at this temperature for 120 min to obtain raw material B.

[0068] (3) Quenching treatment: Raw material B is water-quenched to room temperature to obtain raw material C.

[0069] (4) Pre-aging treatment: Raw material C was heated to 120°C at a rate of 15°C / min and kept at this temperature for 24 h to obtain raw material D.

[0070] (5) Single regression aging treatment: Raw material D was heated to 180°C at a rate of 15°C / min, kept at that temperature for 15 min, and then water-cooled to room temperature to obtain raw material E.

[0071] (6) Re-aging treatment: The raw material E was heated to 120°C at a rate of 15°C / min and kept at this temperature for 24 h to obtain a corrosion-resistant aluminum-zinc-magnesium-copper alloy.

[0072] Comparative Example 4

[0073] As a comparison, the embodiment is different from example 4 in that the time of double regression peak aging is shortened, and the rest of the steps and alloy composition are the same as example 4. The specific steps are as follows:

[0074] (1) Rolling treatment: the aluminum-zinc-magnesium-copper alloy is rolled, the rolling mode is cold rolling, the pass is once, the deformation amount is 40%, and the raw material A is obtained.

[0075] (2) Solution treatment: the aluminum-zinc-magnesium-copper alloy is uniformly heated to 450℃ at a heating rate of 10℃ / min, and the holding time is 100min, and the raw material B is obtained.

[0076] (3) Quenching treatment: the raw material B is water cooled to room temperature to obtain the raw material C.

[0077] (4) Pre-aging treatment: the raw material C is uniformly heated to 130℃ at a heating rate of 10℃ / min, and the holding time is 28h, and the raw material D is obtained.

[0078] (5) Double regression peak aging treatment: the raw material D is uniformly heated to 180℃ at a heating rate of 10℃ / min, and the holding time is 5min, then uniformly heated to 220℃ at a heating rate of 15℃ / min, and the holding time is 5min, and then water cooled to room temperature to obtain the raw material E.

[0079] (6) Re-aging treatment: the raw material E is uniformly heated to 130℃ at a heating rate of 15℃ / min, and the holding time is 28h, and the corrosion-resistant aluminum-zinc-magnesium-copper alloy is obtained.

[0080] Comparative example 5

[0081] As a comparison, the embodiment is different from example 1 in that the Mg element is lacking in the alloy, and the preparation process is exactly the same as example 1. The specific steps are as follows:

[0082] (1) Rolling treatment: the aluminum-zinc-copper alloy is rolled, the rolling mode is cold rolling, the pass is once, the deformation amount is 5%, and the raw material A is obtained.

[0083] (2) Solution treatment: the aluminum-zinc-magnesium-copper alloy is uniformly heated to 430℃ at a heating rate of 15℃ / min, and the holding time is 120min, and the raw material B is obtained.

[0084] (3) Quenching treatment: the raw material B is water cooled to room temperature to obtain the raw material C.

[0085] (4) Pre-aging treatment: the raw material C is uniformly heated to 120℃ at a heating rate of 15℃ / min, and the holding time is 24h, and the raw material D is obtained.

[0086] (5) Double peak aging treatment: the raw material D is uniformly heated to 160°C at a heating rate of 15°C / min, and kept for 15 min, then uniformly heated to 180°C at a heating rate of 15°C / min, and kept for 15 min, and then water quenched to room temperature to obtain raw material E.

[0087] (6) Re-aging treatment: the raw material E is uniformly heated to 120°C at a heating rate of 15°C / min, and kept for 24 h to obtain the corrosion-resistant aluminum-zinc-copper alloy.

[0088] The aluminum alloy samples obtained in Examples 1-4 and Comparative Examples 1-5 are subjected to electrochemical polarization curve test, and the results are shown in Figure 1 Fig. 1. It can be seen from the figure that the corrosion resistance of the aluminum alloy obtained in Example 1 is better than that of Comparative Example 1, because Comparative Example 1 is not rolled, the alloy grain is coarse, and the precipitation of Fe-rich phase is not effectively controlled during aging due to no pre-applied internal stress, resulting in a larger self-corrosion current density and corrosion rate than Example 1. The self-corrosion potential of the aluminum alloy obtained in Example 1 is -1.5359V, the self-corrosion current density is 4.0183x10 -5 A / cm 2 , and the corrosion rate is 0.42462mm / a. The self-corrosion potential of the aluminum alloy in Comparative Example 1 is -1.5603V, the self-corrosion current density is 5.0694x10 -5 A / cm 2 , and the corrosion rate is 0.51836mm / a. The self-corrosion potentials of the two samples are not much different, but the self-corrosion current density and corrosion rate of the aluminum alloy in Example 1 are lower than those of the aluminum alloy in Comparative Example 1, indicating that the corrosion resistance of Example 1 is better.

[0089] It can be seen from Figure 1 that the corrosion resistance of the aluminum alloy obtained in Example 2 is better than that of Comparative Example 2, because Comparative Example 2 does not undergo double peak aging and re-aging treatment, resulting in incomplete precipitation of the strengthening phase MgZn2 phase, which affects the corrosion resistance. The self-corrosion potential of the aluminum alloy obtained in Example 2 is -1.5342V, the self-corrosion current density is 3.96x10 -5 A / cm 2 , and the corrosion rate is 0.41596mm / a. The self-corrosion potential of the aluminum alloy in Comparative Example 2 is -1.5651V, the self-corrosion current density is 4.8316x10 -5 A / cm 2, the corrosion rate is 0.49573 mm / a, the self-corrosion potential of the two samples is not much different, but the self-corrosion current density and the corrosion rate of the aluminum alloy in Example 2 are lower than those of the aluminum alloy in Comparative Example 2, indicating that the corrosion resistance of Example 2 is improved.

[0090] It can be seen from Figure 1 that the corrosion resistance of the aluminum alloy obtained in Example 3 is better than that of Comparative Example 3, because the single regression aging of Comparative Example 3 does not perform high-temperature pre-precipitation of the strengthening phase compared with the double regression peak aging, resulting in incomplete precipitation of the strengthening phase MgZn2 phase, affecting the corrosion resistance thereof, the self-corrosion potential of the aluminum alloy obtained in Example 3 is -1.5338 V, the self-corrosion current density is 3.6236 x 10 -5 A / cm 2 , and the corrosion rate is 0.38493 mm / a. The self-corrosion potential of the aluminum alloy in Comparative Example 3 is -1.5578 V, the self-corrosion current density is 4.3572 x 10 -5 A / cm 2 , and the corrosion rate is 0.45661 mm / a. The self-corrosion potential of the two samples is not much different, but the self-corrosion current density and the corrosion rate of the aluminum alloy in Example 3 are lower than those of the aluminum alloy in Comparative Example 3, indicating that the corrosion resistance of Example 3 is improved.

[0091] It can be seen from Figure 1 that the corrosion resistance of the aluminum alloy obtained in Example 4 is better than that of Comparative Example 4, because the time of the double regression peak aging of Comparative Example 4 is shortened, resulting in insufficient driving force for the GP zone to transform into the strengthening phase MgZn2 phase, affecting the corrosion resistance thereof, the self-corrosion potential of the aluminum alloy obtained in Example 4 is -1.5422 V, the self-corrosion current density is 3.3755 x 10 -5 A / cm 2 , and the corrosion rate is 0.35331 mm / a. The self-corrosion potential of the aluminum alloy in Comparative Example 4 is -1.5504 V, the self-corrosion current density is 4.2456 x 10 -5 A / cm 2 , and the corrosion rate is 0.43738 mm / a. The self-corrosion potential of the two samples is not much different, but the self-corrosion current density and the corrosion rate of the aluminum alloy in Example 4 are lower than those of the aluminum alloy in Comparative Example 4, indicating that the corrosion resistance of Example 4 is improved.

[0092] It can be seen from Figure 1It can be seen that the corrosion resistance of the aluminum alloy obtained in Example 1 is better than that of Comparative Example 5, because Comparative Example 5 lacks the magnesium element, resulting in no precipitation of the strengthening phase MgZn2 phase in the alloy, affecting the corrosion resistance of the alloy. The self-corrosion potential of the aluminum alloy obtained in Example 1 is -1.5359 V, the self-corrosion current density is 4.0183 x 10 -5 A / cm 2 , and the corrosion rate is 0.42462 mm / a. The self-corrosion potential of the aluminum alloy in Comparative Example 5 is -1.5427 V, the self-corrosion current density is 5.1348 x 10 - 5 A / cm 2 , and the corrosion rate is 0.49312 mm / a. The self-corrosion potentials of the two samples are not much different, but the self-corrosion current density and the corrosion rate of the aluminum alloy in Example 1 are lower than those of the aluminum alloy in Comparative Example 5, indicating that the corrosion resistance of Example 1 is improved.

[0093] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method for improving the corrosion resistance of aluminum-zinc-magnesium-copper alloy, characterized by: The corrosion resistance of aluminum-zinc-magnesium-copper alloy is improved by rolling and heat treatment. The processing steps are as follows: (1) Rolling treatment: The aluminum-zinc-magnesium-copper alloy is cold rolled with a deformation of 5% to 40% to obtain raw material A; (2) Solution treatment: Raw material A is heated to 430-450°C at a uniform rate and kept at this temperature for 100-120 min to obtain raw material B; (3) Quenching treatment: quenching raw material B to room temperature to obtain raw material C; (4) Pre-aging treatment: uniformly heat the raw material C to 120-130 °C and keep it at this temperature for 24-28 h to obtain raw material D; (5) Double regression aging treatment: Raw material D is heated uniformly to 160-180°C, kept warm for 15-20 min, then heated uniformly to 180-200°C, kept warm for 15-20 min, and then water-cooled to room temperature to obtain raw material E; (6) Re-aging treatment: uniformly heat the raw material E to 120-130 °C and keep it at this temperature for 24-28 hours to obtain a corrosion-resistant aluminum-zinc-magnesium-copper alloy; The aluminum-zinc-magnesium-copper alloy described in step (1) contains the following components in mass percentage: Cu: 1.2-2.0%, Mg: 2.1-2.9%, Zn: 5.1-6.1%, Cr: 0.18-0.28%, Si≤0.4%, Fe≤0.5%, Mn≤0.3%, Ti≤0.2%, and the rest are Al and unavoidable impurities, and the total mass percentage of all components is 100%.

2. The method for improving the corrosion resistance of aluminum-zinc-magnesium-copper alloy according to claim 1, characterized in that: The rolling method in step (1) is cold rolling, and the rolling pass is one pass.

3. The method for improving the corrosion resistance of aluminum-zinc-magnesium-copper alloy according to claim 1, characterized in that: The uniform heating rate in steps (2), (4), (5) and (6) is 10~15℃ / min.

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