Method for improving intergranular corrosion resistance of 6013 aluminum alloy

Abstract

The invention discloses a method for improving intergranular corrosion resistance of a 6013 aluminum alloy. The method comprises the following steps that the 6013 aluminum alloy is sequentially subjected to solution treatment, quenching, pre-aging treatment and secondary aging treatment. According to the method, the strength of the 6013 aluminum alloy is not affected while the intergranular corrosion resistance of the 6013 aluminum alloy is improved, the industrial production requirement is completely met, and the method is suitable for large-scale industrial application.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloy heat treatment, and in particular to a method for improving the intergranular corrosion resistance of 6013 aluminum alloy. Background Art

[0002] 6013 aluminum alloy belongs to Al-Mg-Si-Cu alloy. Compared with 6061 aluminum alloy and 6063 aluminum alloy, it has better fatigue resistance and machinability, and gradually becomes an ideal substrate for the new generation of electronic structural parts. Under the traditional T6 peak aging treatment, 6013 aluminum alloy has high strength and simple heat treatment process, so 6013 aluminum alloy is widely used in actual production. However, the addition of Cu element increases the intergranular corrosion sensitivity of 6013 aluminum alloy, especially after T6 peak aging treatment, the Cu-containing precipitate phase is continuously distributed between grains, which will significantly reduce the intergranular corrosion resistance of 6013 aluminum alloy. Therefore, the T6 process cannot give full play to the comprehensive performance of 6013 aluminum alloy, which limits the application of 6013 aluminum alloy in corrosive environments.

[0003] CN 112626386 A discloses a method for improving the corrosion resistance of Al-Mg-Si-Cu aluminum alloy, which adopts a two-stage over-aging process (160℃~180℃×16h~24h+200℃~250℃×2h~6h), dissolves the grain boundary precipitation phase in the first low-temperature aging by the second high-temperature aging, cuts off the corrosion channel, and thus improves the intergranular corrosion resistance of the aluminum alloy. However, a long high-temperature aging process will cause the coarsening of the precipitation phase in the grain, which will lead to a decrease in the strength of the aluminum alloy. CN 106319404 A discloses a three-stage aging heat treatment method for aluminum alloy (560℃×40min solid solution + 135℃×6h first aging + 210℃×0.5h second aging + 150℃×12h third aging), which improves the intergranular corrosion performance and strength of the aluminum alloy by three-stage aging. However, the process is complicated and difficult to control, and deviations in temperature and holding time may occur in actual operation. In addition, the process has high requirements for equipment and is difficult to meet the needs of industrial production of aluminum alloys.

[0004] Therefore, it is of great significance to develop a heat treatment method that meets the requirements of industrial production and can improve the intergranular corrosion resistance of 6013 aluminum alloy while maintaining its strength. Summary of the invention

[0005] The object of the present invention is to provide a method for improving the intergranular corrosion resistance of 6013 aluminum alloy.

[0006] The technical solution adopted by the present invention is:

[0007] A method for improving the intergranular corrosion resistance of a 6013 aluminum alloy comprises the following steps: performing solution treatment, quenching, pre-aging treatment and secondary aging treatment on the 6013 aluminum alloy in sequence.

[0008] Preferably, the solution treatment is carried out at a temperature of 540° C. to 550° C., and the time of the solution treatment is 45 min to 60 min.

[0009] Preferably, the quenching method is room temperature water quenching, and the quenching time is 5s to 15s.

[0010] Preferably, the pre-aging treatment is carried out at a temperature of 185° C. to 195° C., and the pre-aging treatment time is 0.5 h to 3 h.

[0011] Preferably, the secondary aging treatment is carried out at a temperature of 140° C. to 160° C., and the time of the secondary aging treatment is 72 h to 120 h.

[0012] Preferably, the time interval between the solution treatment and the quenching is 1s to 5s.

[0013] Preferably, the time interval between the quenching and the pre-aging treatment is 1s to 5s.

[0014] Preferably, the time interval between the pre-aging treatment and the secondary aging treatment does not exceed 72 hours.

[0015] A 6013 aluminum alloy is treated by the method for improving the intergranular corrosion resistance of the 6013 aluminum alloy.

[0016] An electronic product comprising the above 6013 aluminum alloy.

[0017] Principle of the present invention: The present invention sequentially performs solution treatment, quenching, pre-aging treatment and secondary aging treatment on 6013 aluminum alloy, effectively regulating the distribution state of the second phase at the grain boundary of the aluminum alloy material after heat treatment, and improving the intergranular corrosion resistance of the high-copper 6013 aluminum alloy under the premise of meeting the industrial production of extruded aluminum alloy, while keeping its mechanical strength unaffected. Solution treatment dissolves Mg, Si, and Cu alloy elements into the aluminum matrix at a relatively high temperature to form a uniform high-temperature solid solution, thereby improving the mechanical properties and corrosion resistance of the aluminum alloy material. Quenching fixes the supersaturated solid solution by rapid cooling to form a room-temperature supersaturated solid solution, which is conducive to the precipitation of the precipitated phase during the subsequent aging treatment. Pre-aging treatment uses a relatively high aging temperature and a relatively short holding time to partially precipitate the room-temperature supersaturated solid solution and obtain a certain hardening. At this time, the aluminum alloy is in an under-aged state. The secondary aging treatment uses a relatively low aging temperature and a long holding time for the sample, which further precipitates and strengthens the intragranular precipitate phase. At the same time, the distribution morphology of the intergranular precipitate phase is changed from the continuous distribution of the intergranular precipitate phase in T6 aging to a discontinuous distribution, so that the corrosion channels between the precipitates are cut off, thereby improving the intergranular corrosion resistance of the aluminum alloy.

[0018] The beneficial effects of the present invention are as follows: the method of the present invention can improve the intergranular corrosion resistance of the 6013 aluminum alloy while maintaining its strength without being affected, and fully meets the requirements of industrial production, and is suitable for large-scale industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a micrograph of the 6013 aluminum alloy after treatment in Example 1.

[0020] Figure 2 This is a micrograph of the 6013 aluminum alloy after treatment in Example 2.

[0021] Figure 3 This is a micrograph of the 6013 aluminum alloy after treatment in Example 3.

[0022] Figure 4 This is a micrograph of the 6013 aluminum alloy treated in Example 4.

[0023] Figure 5 This is a micrograph of the 6013 aluminum alloy after treatment in Example 5.

[0024] Figure 6 This is a micrograph of the 6013 aluminum alloy after treatment in Comparative Example 1.

[0025] Figure 7 This is a micrograph of the 6013 aluminum alloy after treatment in Comparative Example 2.

[0026] Figure 8This is a micrograph of the 6013 aluminum alloy after treatment in Comparative Example 3.

[0027] Fig. 9 This is a micrograph of the 6013 aluminum alloy after treatment in Comparative Example 4.

[0028] Fig.10 This is a micrograph of the 6013 aluminum alloy after treatment in Comparative Example 5.

[0029] Fig.11 TEM images of 6013 aluminum alloys treated in Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0030] The present invention will be further explained and illustrated below in conjunction with specific embodiments.

[0031] The 6013 aluminum alloy substrate used in Examples 1 to 5 and Comparative Examples 1 to 5 is an extruded 6013 aluminum alloy plate (obtained by casting, homogenization, hot extrusion, online quenching and sawing), and its composition is determined by using an ARL3460 direct reading spectrometer, specifically as follows: in terms of element mass percentage, Si: 0.7%, Mg: 0.9%, Cu: 0.95%, Fe: ≤0.1%, Mn: ≤0.1%, and the remainder is Al and impurities.

[0032] Embodiment 1:

[0033] A method for improving the intergranular corrosion resistance of 6013 aluminum alloy, the steps are as follows:

[0034] 1) The extruded 6013 aluminum alloy sheet was placed in a Nabertherm GmbH N60 / 85HA muffle furnace and solution treated at 540°C for 45 min;

[0035] 2) The extruded 6013 aluminum alloy plate that has completed the solution treatment was immersed in 25°C water and quenched for 10 seconds. The time interval between the solution treatment and quenching was 3 seconds;

[0036] 3) The quenched extruded 6013 aluminum alloy sheet was placed in an aging furnace and subjected to a pre-aging treatment at 185°C for 3 h. The time interval between quenching and pre-aging treatment was 5 s, and then the sheet was taken out and air-cooled to room temperature (25°C);

[0037] 4) The extruded 6013 aluminum alloy sheet that has completed the pre-aging treatment is placed in an aging furnace and subjected to a secondary aging treatment at 160° C. for 120 h. The time interval between the pre-aging treatment and the secondary aging treatment is 0.5 h. The sheet is then taken out and air-cooled to room temperature.

[0038] Embodiment 2:

[0039] A method for improving the intergranular corrosion resistance of 6013 aluminum alloy, the steps are as follows:

[0040] 1) The extruded 6013 aluminum alloy sheet was placed in a Nabertherm GmbH N60 / 85HA muffle furnace and solution treated at 540°C for 45 min;

[0041] 2) The extruded 6013 aluminum alloy plate that has completed the solution treatment was immersed in 25°C water and quenched for 10 seconds. The time interval between the solution treatment and quenching was 3 seconds;

[0042] 3) The quenched extruded 6013 aluminum alloy sheet was placed in an aging furnace and subjected to a pre-aging treatment at 195°C for 0.5 h. The time interval between quenching and pre-aging treatment was 5 s, and then the sheet was taken out and air-cooled to room temperature;

[0043] 4) The extruded 6013 aluminum alloy sheet that has completed the pre-aging treatment is placed in an aging furnace and subjected to a secondary aging treatment at 160° C. for 120 h. The time interval between the pre-aging treatment and the secondary aging treatment is 0.5 h. The sheet is then taken out and air-cooled to room temperature.

[0044] Embodiment 3:

[0045] A method for improving the intergranular corrosion resistance of 6013 aluminum alloy, the steps are as follows:

[0046] 1) The extruded 6013 aluminum alloy sheet was placed in a Nabertherm GmbH N60 / 85HA muffle furnace and solution treated at 540°C for 45 min;

[0047] 2) The extruded 6013 aluminum alloy plate that has completed the solution treatment was immersed in 25°C water and quenched for 10 seconds. The time interval between the solution treatment and quenching was 3 seconds;

[0048] 3) The quenched extruded 6013 aluminum alloy sheet was placed in an aging furnace and subjected to a pre-aging treatment at 185°C for 3 h, with a time interval of 5 s between quenching and pre-aging treatment, and then taken out and placed at room temperature for 72 h;

[0049] 4) The extruded 6013 aluminum alloy sheet that has completed the pre-aging treatment is placed in an aging furnace and subjected to a secondary aging treatment at 140° C. for 120 h. The time interval between the pre-aging treatment and the secondary aging treatment is 72 h. The sheet is then taken out and air-cooled to room temperature.

[0050] Embodiment 4:

[0051] A method for improving the intergranular corrosion resistance of 6013 aluminum alloy, the steps are as follows:

[0052] 1) The extruded 6013 aluminum alloy sheet was placed in a Nabertherm GmbH N60 / 85HA muffle furnace and solution treated at 540°C for 1 h;

[0053] 2) The extruded 6013 aluminum alloy plate that has completed the solution treatment was immersed in 25°C water and quenched for 10 seconds. The time interval between the solution treatment and quenching was 3 seconds;

[0054] 3) The quenched extruded 6013 aluminum alloy sheet was placed in an aging furnace and subjected to a pre-aging treatment at 185°C for 3 hours, with a time interval of 5 seconds between quenching and pre-aging treatment, and then taken out and placed at room temperature for 24 hours;

[0055] 4) The extruded 6013 aluminum alloy sheet that has completed the pre-aging treatment is placed in an aging furnace and subjected to a secondary aging treatment at 160° C. for 72 h. The time interval between the pre-aging treatment and the secondary aging treatment is 24 h. The sheet is then taken out and air-cooled to room temperature.

[0056] Embodiment 5:

[0057] A method for improving the intergranular corrosion resistance of 6013 aluminum alloy, the steps are as follows:

[0058] 1) The extruded 6013 aluminum alloy sheet was placed in a Nabertherm GmbH N60 / 85HA muffle furnace and solution treated at 550°C for 45 min;

[0059] 2) The extruded 6013 aluminum alloy plate that has completed the solution treatment was immersed in 25°C water and quenched for 10 seconds. The time interval between the solution treatment and quenching was 3 seconds;

[0060] 3) The quenched extruded 6013 aluminum alloy sheet was placed in an aging furnace and subjected to a pre-aging treatment at 185°C for 1 h. The time interval between quenching and pre-aging treatment was 5 s, and then the sheet was taken out and air-cooled to room temperature.

[0061] 4) The extruded 6013 aluminum alloy sheet that has completed the pre-aging treatment is placed in an aging furnace and subjected to a secondary aging treatment at 140° C. for 120 h. The time interval between the pre-aging treatment and the secondary aging treatment is 0.5 h. The sheet is then taken out and air-cooled to room temperature.

[0062] Comparative Example 1:

[0063] A heat treatment method for 6013 aluminum alloy, the steps are as follows:

[0064] 1) The extruded 6013 aluminum alloy sheet was placed in a Nabertherm GmbH N60 / 85HA muffle furnace and solution treated at 540°C for 45 min;

[0065] 2) The extruded 6013 aluminum alloy plate that has completed the solution treatment was immersed in 25°C water and quenched for 10 seconds. The time interval between the solution treatment and quenching was 3 seconds;

[0066] 3) The quenched extruded 6013 aluminum alloy sheet was placed in an aging furnace and aged at 185°C for 6 h. The time interval between quenching and aging was 5 s, and then the sheet was taken out and air-cooled to room temperature.

[0067] Comparative Example 2:

[0068] A heat treatment method for 6013 aluminum alloy, the steps are as follows:

[0069] 1) The extruded 6013 aluminum alloy sheet was placed in a Nabertherm GmbH N60 / 85HA muffle furnace and solution treated at 540°C for 1 h;

[0070] 2) The extruded 6013 aluminum alloy plate that has completed the solution treatment was immersed in 25°C water and quenched for 10 seconds. The time interval between the solution treatment and quenching was 3 seconds;

[0071] 3) The quenched extruded 6013 aluminum alloy sheet was placed in an aging furnace and subjected to a pre-aging treatment at 185°C for 9 hours, with a time interval of 5 seconds between quenching and pre-aging treatment, and then taken out and air-cooled to room temperature;

[0072] 4) The extruded 6013 aluminum alloy sheet that has completed the pre-aging treatment is placed in an aging furnace and subjected to a secondary aging treatment at 160° C. for 120 h. The time interval between the pre-aging treatment and the secondary aging treatment is 0.5 h. The sheet is then taken out and air-cooled to room temperature.

[0073] Comparative Example 3:

[0074] A heat treatment method for 6013 aluminum alloy, the steps are as follows:

[0075] 1) The extruded 6013 aluminum alloy sheet was placed in a Nabertherm GmbH N60 / 85HA muffle furnace and solution treated at 540°C for 45 min;

[0076] 2) The extruded 6013 aluminum alloy plate that has completed the solution treatment was immersed in 25°C water and quenched for 10 seconds. The time interval between the solution treatment and quenching was 3 seconds;

[0077] 3) The quenched extruded 6013 aluminum alloy sheet was placed in an aging furnace and subjected to a pre-aging treatment at 195°C for 0.5 h. The time interval between quenching and pre-aging treatment was 5 s, and then the sheet was taken out and air-cooled to room temperature;

[0078] 4) The extruded 6013 aluminum alloy sheet that has completed the pre-aging treatment is placed in an aging furnace and subjected to a secondary aging treatment at 160° C. for 500 h. The time interval between the pre-aging treatment and the secondary aging treatment is 0.5 h. The sheet is then taken out and air-cooled to room temperature.

[0079] Comparative Example 4:

[0080] A heat treatment method for 6013 aluminum alloy, the steps are as follows:

[0081] 1) The extruded 6013 aluminum alloy sheet was placed in a Nabertherm GmbH N60 / 85HA muffle furnace and solution treated at 540°C for 45 min;

[0082] 2) The extruded 6013 aluminum alloy plate that has completed the solution treatment was immersed in 25°C water and quenched for 10 seconds. The time interval between the solution treatment and quenching was 3 seconds;

[0083] 3) The quenched extruded 6013 aluminum alloy sheet was placed in an aging furnace and subjected to a pre-aging treatment at 220°C for 3 h, with a time interval of 5 s between quenching and pre-aging treatment, and then taken out and air-cooled to room temperature;

[0084] 4) The extruded 6013 aluminum alloy sheet that has completed the pre-aging treatment is placed in an aging furnace and subjected to a secondary aging treatment at 140° C. for 120 h. The time interval between the pre-aging treatment and the secondary aging treatment is 0.5 h. The sheet is then taken out and air-cooled to room temperature.

[0085] Comparative Example 5:

[0086] A heat treatment method for 6013 aluminum alloy, the steps are as follows:

[0087] 1) The extruded 6013 aluminum alloy sheet was placed in a Nabertherm GmbH N60 / 85HA muffle furnace and solution treated at 550°C for 45 min;

[0088] 2) The extruded 6013 aluminum alloy plate that has completed the solution treatment was immersed in 25°C water and quenched for 10 seconds. The time interval between the solution treatment and quenching was 3 seconds;

[0089] 3) The quenched extruded 6013 aluminum alloy sheet was placed in an aging furnace and subjected to a pre-aging treatment at 185°C for 3 hours, with a time interval of 5 seconds between quenching and pre-aging treatment, and then taken out and placed at room temperature for 24 hours;

[0090] 4) The extruded 6013 aluminum alloy sheet that has completed the pre-aging treatment is placed in an aging furnace and subjected to a secondary aging treatment at 120° C. for 120 h. The time interval between the pre-aging treatment and the secondary aging treatment is 24 h. The sheet is then taken out and air-cooled to room temperature.

[0091] Performance Testing:

[0092] 1) The key parameters of the heat treatment process in Examples 1 to 5 and Comparative Examples 1 to 5 and the tensile properties test results of the treated 6013 aluminum alloy are shown in the following table:

[0093] Table 1 Key parameters of heat treatment process and tensile properties test results of 6013 aluminum alloy after treatment

[0094]

[0095]

[0096] Note:

[0097] Tensile properties: The test was carried out on an MTSExceedE45 electronic universal testing machine with reference to "GB / T228.1-2021 Tensile test of metal materials Part 1 Room temperature test method". The plate was processed into a dumbbell shape with reference to "GB / T 16865-2023 Specimens and methods for tensile test of deformed aluminum, magnesium and their alloy products". The test was conducted three times at room temperature (25°C) and the average value was taken.

[0098] From Table 1, we can see that:

[0099] a) The tensile strength of the 6013 aluminum alloy after treatment in Examples 1 to 5 is significantly higher than that of the 6013 aluminum alloy after T6 peak aging treatment (Comparative Example 1), indicating that the method of the present invention can improve the strength of the 6013 aluminum alloy, and the toughness of the 6013 aluminum alloy is equivalent to that of the 6013 aluminum alloy after T6 peak aging treatment;

[0100] b) Since the pre-aging time in Comparative Example 2 is too long (9h), the secondary aging in Comparative Example 3 is too long (500h), the pre-aging temperature in Comparative Example 4 is too high (220°C), and the secondary aging treatment temperature in Comparative Example 5 is too low (120°C), the tensile strength of the 6013 aluminum alloys treated in Comparative Examples 2 to 5 is lower than that of the 6013 aluminum alloys treated in Examples 1 to 5, and the tensile strength of the 6013 aluminum alloy treated in Comparative Example 5 is improved, but the yield strength is significantly lower than that of the 6013 aluminum alloy after T6 peak aging treatment.

[0101] 2) The key parameters of the heat treatment process in Examples 1 to 5 and Comparative Examples 1 to 5 and the intergranular corrosion test results of the 6013 aluminum alloy after treatment are shown in the following table (the micrographs of the 6013 aluminum alloy after treatment in Examples 1 to 5 and Comparative Examples 1 to 5 are shown in Figures 1 to 10 shown):

[0102] Table 2 Key parameters of heat treatment process and intergranular corrosion test results of 6013 aluminum alloy after treatment

[0103]

[0104] Note:

[0105] Intergranular corrosion: Tested in accordance with "GB / T 7998-2023 Evaluation Method for Intergranular Corrosion Sensitivity of Aluminum Alloys". After degreasing, pickling and alkali washing, the samples were placed in a corrosion solution (57 g / L NaCl + 10 mL / L H 2 O 2 +1000mL of H 2 After immersion in water for 24 h, the metallographic specimens were prepared and the corrosion behavior was observed directly on a Leica DM2700M metallographic microscope after polishing.

[0106] From Table 1, Table 2 and Figures 1 to 10 It can be seen that:

[0107] a) The intergranular corrosion depth of the 6013 aluminum alloys treated in Examples 1 to 5 is less than that of the 6013 aluminum alloys treated with T6 peak aging (Comparative Example 1), indicating that the corrosion resistance of the 6013 aluminum alloys treated in Examples 1 to 5 is improved, and the intergranular corrosion resistance and strength of the 6013 aluminum alloy are improved simultaneously. In particular, Examples 1 and 2 significantly improve the intergranular corrosion resistance of the 6013 aluminum alloy. The tensile strength of the 6013 aluminum alloy treated in Example 1 is increased by 10.8 MPa compared with that of the 6013 aluminum alloy treated in Comparative Example 1, and the yield strength is increased by 10.35 MPa;

[0108] b) After 72 hours of storage in Example 3, the mechanical properties of the treated 6013 aluminum alloy are slightly lower than those of the 6013 aluminum alloy treated in Example 1, but its intergranular corrosion resistance is significantly improved compared with the 6013 aluminum alloy after T6 peak aging treatment (Comparative Example 1), indicating that the method of the present invention can still significantly improve the intergranular corrosion resistance of the 6013 aluminum alloy under the actual storage process conditions of the factory.

[0109] 3) Transmission electron microscopy (TEM) images of the 6013 aluminum alloy treated in Example 1 and Comparative Example 1 are as follows: Fig.11 (a is the 6013 aluminum alloy treated in Example 1, b is the 6013 aluminum alloy treated in Comparative Example 1) (the microstructure of the sample was observed using a Talos F200X transmission electron microscope at 200 kV, and the sample preparation method was: the sample was mechanically ground to a thickness of about 0.1 mm, and then thinned using a Gatan 691 ion thinning device).

[0110] Depend on Fig.11It can be seen that the intergranular precipitation phase of the 6013 aluminum alloy treated in Example 1 presents a discontinuous point distribution, while the intergranular precipitation phase of the 6013 aluminum alloy treated in Comparative Example 1 presents a continuous distribution, indicating that the method of the present invention cuts off the intergranular corrosion channel and greatly improves the intergranular corrosion resistance of the 6013 aluminum alloy.

[0111] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for improving the intergranular corrosion resistance of 6013 aluminum alloy, characterized in that: The following steps are involved: The 6013 aluminum alloy was subjected to solution treatment, quenching, pre-aging treatment and secondary aging treatment in sequence.

2. The method for improving the intergranular corrosion resistance of 6013 aluminum alloy according to claim 1, characterized in that: The solution treatment is carried out at a temperature of 540° C. to 550° C., and the time of the solution treatment is 45 min to 60 min.

3. The method for improving the intergranular corrosion resistance of 6013 aluminum alloy according to claim 1, characterized in that: The quenching method is room temperature water quenching, and the quenching time is 5s to 15s.

4. The method for improving the intergranular corrosion resistance of 6013 aluminum alloy according to claim 1, characterized in that: The pre-aging treatment is carried out at a temperature of 185° C. to 195° C., and the pre-aging treatment time is 0.5 h to 3 h.

5. The method for improving the intergranular corrosion resistance of 6013 aluminum alloy according to claim 1, characterized in that: The secondary aging treatment is carried out at a temperature of 140° C. to 160° C., and the time of the secondary aging treatment is 72 h to 120 h.

6. The method for improving the intergranular corrosion resistance of 6013 aluminum alloy according to any one of claims 1 to 5, characterized in that: The time interval between the solution treatment and the quenching is 1s to 5s.

7. The method for improving the intergranular corrosion resistance of 6013 aluminum alloy according to any one of claims 1 to 5, characterized in that: The time interval between the quenching and the pre-aging treatment is 1s to 5s.

8. The method for improving the intergranular corrosion resistance of 6013 aluminum alloy according to any one of claims 1 to 5, characterized in that: The time interval between the pre-aging treatment and the secondary aging treatment shall not exceed 72 hours.

9. A 6013 aluminum alloy, characterized in that: The 6013 aluminum alloy is treated by the method for improving the intergranular corrosion resistance of the 6013 aluminum alloy as described in any one of claims 1 to 8.

10. An electronic product, characterized in that: Contains the 6013 aluminum alloy described in claim 9.

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