A 7 series aluminum alloy communication tower profile and preparation method thereof

Abstract

The present invention provides a 7-series aluminum alloy communication pole tower profile and a preparation method thereof, comprising the following components in mass percentage: Zn 6.4-6.6%, Mn 0.2-0.4%, Mg 1.6-2.0%, Cu 0.3-0.4%, Si ≤ 0.15%, Fe ≤ 0.3%, Sc 0.2-0.3%, Er 0.1-0.2%, Cr 0.15-0.22%, Zr 0.1-0.2%, Ti ≤ 0.1%, other single impurity elements ≤ 0.05%, total impurity content ≤ 0.15%, and the balance is Al. The mechanical properties and anti-corrosion ability of the aluminum alloy communication pole tower profile prepared by the present invention are comprehensively improved by combining the design of aluminum alloy elements and content and the processing technology, which is of great significance to reducing the cost of communication pole towers and improving the safety of use.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum alloy materials, and in particular relates to a 7 series aluminum alloy communication pole tower profile and a preparation method thereof. Background Art

[0002] Communication poles are mainly used as antenna supports or as transmitters. They are a type of signal transmission tower, also called signal transmission towers or signal towers. Their main function is to support signal transmission and to support signal transmission antennas. As a key facility in modern communication networks, the material selection of communication poles is crucial to ensure the stability and reliability of communication signal transmission. Conventional communication poles are made of steel and need to be anti-corrosive by hot-dip galvanizing. During the galvanizing process, waste gas, wastewater and zinc slag will be discharged, polluting the environment. In addition, the steel has a large density and is often bulky and heavy, which brings inconvenience to transportation and installation. 7 series aluminum alloy is a heat-treatable strengthening alloy. After solution treatment, it has high strength and plasticity, and good low-temperature strength. In the early days, 7 series aluminum alloy was mainly used in the aerospace field, so it was called "aviation aluminum". Due to its excellent comprehensive performance, it is now gradually used in the construction of communication towers. Aluminum alloy has a low density, which makes the communication tower have a lighter weight and better durability. It is suitable for places that need to reduce weight, improve wind resistance and reduce maintenance costs.

[0003] As the main body of the communication tower that carries the conductors and hardware, its safe and reliable operation is the basis for the transmission of communication signals. Since the tower body is located in an outdoor environment, it is easy to rust due to wind, rain or atmospheric corrosion. The operating strength of the tower body will be greatly reduced, and the operating life will be seriously shortened, which will bring major hidden dangers to the safe operation of the system. However, the existing aluminum alloy communication tower profiles have poor corrosion resistance and pose great safety hazards. At the same time, the 7 series aluminum alloys used for communication tower profiles on the market are mainly medium-high strength 7 series aluminum alloys with a strength of less than 500MPa. How to achieve a balance between the ultra-high strength and corrosion resistance of aluminum alloys remains to be broken through. Summary of the invention

[0004] The purpose of the present invention is to provide a 7 series aluminum alloy communication pole tower profile and a preparation method thereof. By combining the design of alloy elements and contents with the treatment process, the mechanical properties and corrosion resistance of the prepared aluminum alloy communication pole tower profile are comprehensively improved, which is of great significance to reducing the cost of communication pole towers and improving safety in use.

[0005] In order to achieve the above-mentioned purpose, the present invention provides the following technical scheme: a 7 series aluminum alloy communication pole tower profile, comprising the following components in mass percentage: Zn 6.4-6.6%, Mn 0.2-0.4%, Mg 1.6-2.0%, Cu 0.3-0.4%, Si ≤ 0.15%, Fe ≤ 0.3%, Sc 0.2-0.3%, Er 0.1-0.2%, Cr 0.15-0.22%, Zr 0.1-0.2%, Ti ≤ 0.1%, the remaining single impurity elements ≤ 0.05%, the total impurity content ≤ 0.15%, and the balance is Al.

[0006] Furthermore, the sum of the mass percentages of Sc, Er and Cr is ≤0.6%.

[0007] Adding Sc and Er to the aluminum alloy system of the present invention can greatly improve the mechanical properties of the aluminum alloy. It is speculated that the dispersed phase formed after adding Sc and Er is evenly distributed on the matrix, which plays a role in precipitation strengthening, and can synergistically promote the nucleation of the aluminum alloy, thereby refining the grains and improving its toughness. Adding Mg elements to 7 series aluminum alloys can effectively improve the strength of aluminum alloys, but the inventors found that when the Mg content is too high, it will lead to an increase in the sensitivity of aluminum alloys to intergranular corrosion. The inventors unexpectedly discovered that when Sc, Er and Cr are added to the system of the present invention at the same time, and the sum of the mass percentages of Sc, Er and Cr is ≤0.6%, the intergranular corrosion resistance of the aluminum alloy can be improved. It is speculated that under this condition, the grains formed inside the aluminum alloy are finer and the structure is uniform, while the layered grain structure of the aluminum alloy is weakened, reducing the wedging effect of corrosion products.

[0008] Furthermore, the following components are included in mass percentage: Zn 6.5%, Mn 0.3%, Mg 1.8%, Cu 0.35%, Si 0.1%, Fe 0.15%, Sc 0.23%, Er 0.13%, Cr 0.18%, Zr 0.17%, Ti 0.05%, other single impurity elements ≤ 0.05%, total impurity content ≤ 0.15%, and the balance is Al.

[0009] The present invention also provides a method for preparing a 7 series aluminum alloy communication tower profile, comprising the following steps:

[0010] (1) Weigh the corresponding raw materials according to the composition of the aluminum alloy;

[0011] (2) melting the prepared aluminum alloy raw material at 750-760° C. and casting it into an aluminum alloy ingot;

[0012] (3) subjecting the aluminum alloy ingot to a two-stage homogenization treatment;

[0013] (4) Extruding the ingot after the double-stage homogenization treatment: the heating temperature of the aluminum alloy ingot is 450-470° C., the heating temperature of the extrusion barrel is 480-500° C., the extrusion ratio is 20:1, and the extrusion speed is 1.5-1.7 mm / min to obtain an aluminum alloy profile;

[0014] (5) Online quenching of the aluminum alloy profile: the quenching method is spraying, the water temperature is 20-30°C, and the spraying speed is 15-20m / s;

[0015] (6) The quenched aluminum alloy profile is subjected to a double-stage aging heat treatment and air-cooled to room temperature to obtain a 7 series aluminum alloy communication pole tower profile.

[0016] Furthermore, the two-stage homogenization treatment is specifically: keeping the temperature at 450-460° C. for 8-10 hours, and then keeping the temperature at 480-490° C. for 16-18 hours.

[0017] Furthermore, the steps of the double-stage aging heat treatment are as follows: the first stage aging heat treatment: the aging temperature is 100-105°C, and the holding time is 10-12h; then the aging temperature of the aluminum alloy profile is returned to 200-210°C within 20-30min and then quenched, the quenching method is spraying, the water temperature is 15-20°C, and the spraying speed is 10-15m / s; and then the second stage aging heat treatment is performed, the aging temperature is 150-155°C, and the holding time is 15-17h.

[0018] Furthermore, the heating temperature of the aluminum alloy ingot is 460° C., the heating temperature of the extrusion barrel is 490° C., the extrusion ratio is 20:1, and the extrusion speed is 1.6 mm / min, to obtain an aluminum alloy profile.

[0019] Furthermore, the steps of the double-stage aging heat treatment are as follows: the first-stage aging heat treatment: the aging temperature is 102°C, and the holding time is 11h; then the aging temperature of the aluminum alloy profile is returned to 205°C within 25min and then quenched, and then the second-stage aging heat treatment is performed: the aging temperature is 153°C, and the holding time is 16h.

[0020] In the process of preparing the aluminum alloy of the present invention, it is found that while maintaining the high strength of the aluminum alloy, there will be a relatively obvious stress corrosion phenomenon, and communication towers will inevitably have stress during use, which restricts the application of aluminum alloys in communication towers. The present invention uses a two-stage homogenization treatment and a two-stage aging heat treatment to synergize the effect, so that the prepared aluminum alloy can maintain high strength while making the aluminum alloy have good stress corrosion resistance, achieving a balance between the two.

[0021] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0022] 1. The present invention provides a 7-series aluminum alloy communication pole tower profile and a preparation method thereof. Through the design and optimization of alloy components, the mechanical performance strength that can replace steel is achieved. The aluminum alloy of the present invention has an excellent organizational structure and high resistance to intergranular corrosion and stress corrosion. The aluminum alloy prepared by the present invention broadens the application scope of the 7-series aluminum alloy. It can not only be used in the construction of communication pole towers, but also opens up new material replacement solutions for industries such as new energy vehicles, high-end electronics, and power communications.

[0023] 2. Adding Sc and Er to the aluminum alloy system of the present invention can greatly improve the mechanical properties of the aluminum alloy. At the same time, adding Mg to the 7-series aluminum alloy can effectively improve the strength of the aluminum alloy, but the inventors found that when the Mg content is too high, the intergranular corrosion sensitivity of the aluminum alloy will increase. When Sc, Er and Cr are added to the system of the present invention at the same time, and the sum of the mass percentages of Sc, Er and Cr is ≤0.6%, the intergranular corrosion resistance of the aluminum alloy can be improved.

[0024] 3. Communication poles and towers will inevitably have stress during use, which restricts their application in communication towers. The present invention uses a two-stage homogenization treatment and a two-stage aging heat treatment to synergize the effect, so that the prepared aluminum alloy has good stress corrosion resistance while maintaining high strength. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Example 1

[0027] The present embodiment provides a 7 series aluminum alloy communication pole tower profile, including the following components in mass percentage: Zn 6.5%, Mn 0.3%, Mg 1.8%, Cu 0.35%, Si 0.1%, Fe 0.15%, Sc 0.23%, Er 0.13%, Cr 0.18%, Zr 0.17%, Ti 0.05%, the remaining individual impurity elements ≤ 0.05%, the total impurity content ≤ 0.15%, and the balance is Al.

[0028] The method for preparing the 7 series aluminum alloy communication tower profile comprises the following steps:

[0029] (1) Weigh the corresponding raw materials according to the composition of the aluminum alloy;

[0030] (2) melting the prepared aluminum alloy raw material at 755° C. and casting it into an aluminum alloy ingot;

[0031] (3) subjecting the aluminum alloy ingot to a two-stage homogenization treatment; the two-stage homogenization treatment specifically comprises: keeping the temperature at 455° C. for 9 hours, and then keeping the temperature at 485° C. for 17 hours;

[0032] (4) Extruding the ingot after the double-stage homogenization treatment: the heating temperature of the aluminum alloy ingot is 460° C., the heating temperature of the extrusion barrel is 490° C., the extrusion ratio is 20:1, and the extrusion speed is 1.6 mm / min to obtain an aluminum alloy profile;

[0033] (5) The aluminum alloy profile is quenched online: the quenching method is spraying, the water temperature is 25°C, and the spraying speed is 18m / s;

[0034] (6) The aluminum alloy profile after quenching treatment is subjected to a double-stage aging heat treatment, and the steps of the double-stage aging heat treatment are as follows: the first stage aging heat treatment: the aging temperature is 102°C, and the holding time is 11h; then the aging temperature of the aluminum alloy profile is returned to 205°C within 25min and then quenched, the quenching method is spraying, the water temperature is 17°C, and the spraying speed is 12m / s; and then the second stage aging heat treatment is performed: the aging temperature is 153°C, and the holding time is 16h.

[0035] Example 2

[0036] The present embodiment provides a 7 series aluminum alloy communication pole tower profile, including the following components in mass percentage: Zn 6.4%, Mn 0.4%, Mg 1.6%, Cu 0.4%, Si 0.15%, Fe 0.1%, Sc 0.2%, Er 0.1%, Cr 0.15%, Zr 0.2%, Ti 0.1%, and the remaining individual impurity elements ≤ 0.05%, the total impurity content ≤ 0.15%, and the balance is Al.

[0037] The method for preparing the 7 series aluminum alloy communication tower profile comprises the following steps:

[0038] (1) Weigh the corresponding raw materials according to the composition of the aluminum alloy;

[0039] (2) melting the prepared aluminum alloy raw material at 750° C. and casting it into an aluminum alloy ingot;

[0040] (3) subjecting the aluminum alloy ingot to a two-stage homogenization treatment; the two-stage homogenization treatment specifically comprises: keeping the temperature at 460° C. for 8 hours, and then keeping the temperature at 480° C. for 16 hours;

[0041] (4) Extruding the ingot after the double-stage homogenization treatment: the heating temperature of the aluminum alloy ingot is 450° C., the heating temperature of the extrusion barrel is 480° C., the extrusion ratio is 20:1, and the extrusion speed is 1.5 mm / min to obtain an aluminum alloy profile;

[0042] (5) The aluminum alloy profile is quenched online: the quenching method is spraying, the water temperature is 30°C, and the spraying speed is 20m / s;

[0043] (6) The aluminum alloy profile after quenching treatment is subjected to a double-stage aging heat treatment, and the steps of the double-stage aging heat treatment are as follows: the first stage aging heat treatment: the aging temperature is 100°C, and the holding time is 12h; then the aging temperature of the aluminum alloy profile is returned to 210°C within 20min and then quenched, the quenching method is spraying, the water temperature is 15°C, and the spraying speed is 15m / s; then the second stage aging heat treatment is performed, the aging temperature is 150°C, and the holding time is 17h; air cooling is performed to room temperature to obtain a 7 series aluminum alloy communication pole tower profile.

[0044] Comparative Example 1

[0045] The difference between this comparative example and Example 1 is that the composition of the 7 series aluminum alloy communication pole tower profile does not contain Sc.

[0046] Specifically: a 7 series aluminum alloy communication pole tower profile, including the following components in mass percentage: Zn 6.5%, Mn 0.3%, Mg 1.8%, Cu 0.35%, Si 0.1%, Fe 0.15%, Er 0.13%, Cr 0.18%, Zr 0.17%, Ti 0.05%, other single impurity elements ≤ 0.05%, total impurity content ≤ 0.15%, and the balance is Al.

[0047] The method for preparing the 7 series aluminum alloy communication tower profile comprises the following steps:

[0048] (1) Weigh the corresponding raw materials according to the composition of the aluminum alloy;

[0049] (2) melting the prepared aluminum alloy raw material at 755° C. and casting it into an aluminum alloy ingot;

[0050] (3) subjecting the aluminum alloy ingot to a two-stage homogenization treatment; the two-stage homogenization treatment specifically comprises: keeping the temperature at 455° C. for 9 hours, and then keeping the temperature at 485° C. for 17 hours;

[0051] (4) Extruding the ingot after the double-stage homogenization treatment: the heating temperature of the aluminum alloy ingot is 460° C., the heating temperature of the extrusion barrel is 490° C., the extrusion ratio is 20:1, and the extrusion speed is 1.6 mm / min to obtain an aluminum alloy profile;

[0052] (5) The aluminum alloy profile is quenched online: the quenching method is spraying, the water temperature is 25°C, and the spraying speed is 18m / s;

[0053] (6) The aluminum alloy profile after quenching treatment is subjected to a double-stage aging heat treatment, and the steps of the double-stage aging heat treatment are as follows: the first stage aging heat treatment: the aging temperature is 102°C, and the holding time is 11h; then the aging temperature of the aluminum alloy profile is returned to 205°C within 25min and then quenched, the quenching method is spraying, the water temperature is 17°C, and the spraying speed is 12m / s; and then the second stage aging heat treatment is performed: the aging temperature is 153°C, and the holding time is 16h.

[0054] Comparative Example 2

[0055] The difference between this comparative example and Example 1 is that the composition of the 7 series aluminum alloy communication pole tower profile does not contain Er.

[0056] Specifically: a 7 series aluminum alloy communication pole tower profile, including the following components in mass percentage: Zn6.5%, Mn0.3%, Mg1.8%, Cu0.35%, Si 0.1%, Fe 0.15%, Sc0.23%, Cr0.18%, Zr0.17%, Ti0.05%, other single impurity elements ≤0.05%, total impurity content ≤0.15%, and the balance is Al.

[0057] The method for preparing the 7 series aluminum alloy communication tower profile comprises the following steps:

[0058] (1) Weigh the corresponding raw materials according to the composition of the aluminum alloy:

[0059] (2) melting the prepared aluminum alloy raw material at 755° C. and casting it into an aluminum alloy ingot;

[0060] (3) subjecting the aluminum alloy ingot to a two-stage homogenization treatment; the two-stage homogenization treatment specifically comprises: keeping the temperature at 455° C. for 9 hours, and then keeping the temperature at 485° C. for 17 hours;

[0061] (4) Extruding the ingot after the double-stage homogenization treatment: the heating temperature of the aluminum alloy ingot is 460° C., the heating temperature of the extrusion barrel is 490° C., the extrusion ratio is 20:1, and the extrusion speed is 1.6 mm / min to obtain an aluminum alloy profile;

[0062] (5) The aluminum alloy profile is quenched online: the quenching method is spraying, the water temperature is 25°C, and the spraying speed is 18m / s;

[0063] (6) The aluminum alloy profile after quenching treatment is subjected to a double-stage aging heat treatment, and the steps of the double-stage aging heat treatment are as follows: the first stage aging heat treatment: the aging temperature is 102°C, and the holding time is 11h; then the aging temperature of the aluminum alloy profile is returned to 205°C within 25min and then quenched, the quenching method is spraying, the water temperature is 17°C, and the spraying speed is 12m / s; and then the second stage aging heat treatment is performed: the aging temperature is 153°C, and the holding time is 16h.

[0064] Comparative Example 3

[0065] The difference between this comparative example and Example 1 is that the composition of the 7 series aluminum alloy communication pole tower profile does not contain Cr.

[0066] Specifically: a 7 series aluminum alloy communication pole tower profile, including the following components in mass percentage: Zn 6.5%, Mn 0.3%, Mg 1.8%, Cu 0.35%, Si 0.1%, Fe 0.15%, Sc 0.23%, Er 0.13%, Zr 0.17%, Ti 0.05%, other single impurity elements ≤ 0.05%, total impurity content ≤ 0.15%, and the balance is Al.

[0067] The method for preparing the 7 series aluminum alloy communication tower profile comprises the following steps:

[0068] (1) Weigh the corresponding raw materials according to the composition of the aluminum alloy:

[0069] (2) melting the prepared aluminum alloy raw material at 755° C. and casting it into an aluminum alloy ingot;

[0070] (3) subjecting the aluminum alloy ingot to a two-stage homogenization treatment: the two-stage homogenization treatment specifically comprises: keeping the temperature at 455° C. for 9 hours, and then keeping the temperature at 485° C. for 17 hours;

[0071] (4) Extruding the ingot after the double-stage homogenization treatment: the heating temperature of the aluminum alloy ingot is 460° C., the heating temperature of the extrusion barrel is 490° C., the extrusion ratio is 20:1, and the extrusion speed is 1.6 mm / min to obtain an aluminum alloy profile;

[0072] (5) The aluminum alloy profile is quenched online: the quenching method is spraying, the water temperature is 25°C, and the spraying speed is 18m / s;

[0073] (6) The aluminum alloy profile after quenching treatment is subjected to a double-stage aging heat treatment, and the steps of the double-stage aging heat treatment are as follows: the first stage aging heat treatment: the aging temperature is 102°C, and the holding time is 11h; then the aging temperature of the aluminum alloy profile is returned to 205°C within 25min and then quenched, the quenching method is spraying, the water temperature is 17°C, and the spraying speed is 12m / s; and then the second stage aging heat treatment is performed: the aging temperature is 153°C, and the holding time is 16h.

[0074] Comparative Example 4

[0075] The difference between this comparative example and Example 1 is that the sum of the mass percentages of Sc, Er and Cr is greater than 0.6%.

[0076] Specifically: a 7 series aluminum alloy communication pole tower profile, including the following components in mass percentage: Zn6.5%, Mn0.3%, Mg1.8%, Cu0.35%, Si 0.1%, Fe 0.15%, Sc0.3%, Er0.2%, Cr0.22%, Zr0.17%, Ti 0.05%, other single impurity elements ≤0.05%, total impurity content ≤0.15%, and the balance is Al.

[0077] The method for preparing the 7 series aluminum alloy communication tower profile comprises the following steps:

[0078] (1) Weigh the corresponding raw materials according to the composition of the aluminum alloy:

[0079] (2) melting the prepared aluminum alloy raw material at 755° C. and casting it into an aluminum alloy ingot;

[0080] (3) subjecting the aluminum alloy ingot to a two-stage homogenization treatment; the two-stage homogenization treatment specifically comprises: keeping the temperature at 455° C. for 9 hours, and then keeping the temperature at 485° C. for 17 hours;

[0081] (4) Extruding the ingot after the double-stage homogenization treatment: the heating temperature of the aluminum alloy ingot is 460° C., the heating temperature of the extrusion barrel is 490° C., the extrusion ratio is 20:1, and the extrusion speed is 1.6 mm / min to obtain an aluminum alloy profile;

[0082] (5) The aluminum alloy profile is quenched online: the quenching method is spraying, the water temperature is 25°C, and the spraying speed is 18m / s;

[0083] (6) The aluminum alloy profile after quenching treatment is subjected to a double-stage aging heat treatment, and the steps of the double-stage aging heat treatment are as follows: the first stage aging heat treatment: the aging temperature is 102°C, and the holding time is 11h; then the aging temperature of the aluminum alloy profile is returned to 205°C within 25min and then quenched, the quenching method is spraying, the water temperature is 17°C, and the spraying speed is 12m / s; and then the second stage aging heat treatment is performed: the aging temperature is 153°C, and the holding time is 16h.

[0084] Comparative Example 5

[0085] The difference between this comparative example and Example 1 is that the mass percentages of various components of the 7 series aluminum alloy communication pole tower profile are changed.

[0086] Specifically: a 7 series aluminum alloy communication pole tower profile, Zn6.0%, Mn0.45%, Mg2.2%, Cu0.25%, Si0.15%, Fe0.3%, Sc0.23%, Er0.13%, Cr0.18%, Zr0.17%, Ti 0.05%, other single impurity elements ≤0.05%, total impurity content ≤0.15%, and the balance is Al.

[0087] The method for preparing the 7 series aluminum alloy communication tower profile comprises the following steps:

[0088] (1) Weigh the corresponding raw materials according to the composition of the aluminum alloy;

[0089] (2) melting the prepared aluminum alloy raw material at 755° C. and casting it into an aluminum alloy ingot;

[0090] (3) subjecting the aluminum alloy ingot to a two-stage homogenization treatment; the two-stage homogenization treatment specifically comprises: keeping the temperature at 455° C. for 9 hours, and then keeping the temperature at 485° C. for 17 hours;

[0091] (4) Extruding the ingot after the double-stage homogenization treatment: the heating temperature of the aluminum alloy ingot is 460° C., the heating temperature of the extrusion barrel is 490° C., the extrusion ratio is 20:1, and the extrusion speed is 1.6 mm / min to obtain an aluminum alloy profile;

[0092] (5) The aluminum alloy profile is quenched online: the quenching method is spraying, the water temperature is 25°C, and the spraying speed is 18m / s;

[0093] (6) The aluminum alloy profile after quenching treatment is subjected to a double-stage aging heat treatment, and the steps of the double-stage aging heat treatment are as follows: the first stage aging heat treatment: the aging temperature is 102°C, and the holding time is 11h; then the aging temperature of the aluminum alloy profile is returned to 205°C within 25min and then quenched, the quenching method is spraying, the water temperature is 17°C, and the spraying speed is 12m / s; and then the second stage aging heat treatment is performed: the aging temperature is 153°C, and the holding time is 16h.

[0094] Comparative Example 6

[0095] The difference between this comparative example and Example 1 is that the preparation method of the 7 series aluminum alloy communication pole tower profile is changed.

[0096] Specifically: a 7 series aluminum alloy communication pole tower profile, including the following components in mass percentage: Zn 6.5%, Mn 0.3%, Mg 1.8%, Cu 0.35%, Si 0.1%, Fe 0.15%, Sc 0.23%, Er 0.13%, Cr 0.18%, Zr 0.17%, Ti 0.05%, other single impurity elements ≤ 0.05%, total impurity content ≤ 0.15%, and the balance is Al.

[0097] The method for preparing the 7 series aluminum alloy communication tower profile comprises the following steps:

[0098] (1) Weigh the corresponding raw materials according to the composition of the aluminum alloy;

[0099] (2) melting the prepared aluminum alloy raw material at 755° C. and casting it into an aluminum alloy ingot;

[0100] (3) Extruding the ingot: the heating temperature of the aluminum alloy ingot is 460° C., the heating temperature of the extrusion barrel is 490° C., the extrusion ratio is 20:1, and the extrusion speed is 1.6 mm / min, to obtain an aluminum alloy profile;

[0101] (4) The aluminum alloy profile is quenched online: the quenching method is spraying, the water temperature is 25°C, and the spraying speed is 18m / s;

[0102] (5) The aluminum alloy profile after quenching is subjected to a two-stage aging heat treatment at 110°C for 5 h and 160°C for 10 h.

[0103] Performance Testing

[0104] The mechanical properties of the aluminum alloy communication tower profiles prepared in Examples 1-2 and Comparative Examples 1-6 were determined with reference to GB-T 228-2002; the intergranular corrosion test of the aluminum alloy communication tower profiles prepared in Examples 1-2 and Comparative Examples 1-6 was performed with reference to GB / T 7998-2005; the stress corrosion resistance of the aluminum alloy communication tower profiles prepared in Examples 1-2 and Comparative Examples 1-6 was tested, with a thickness of 6 mm, measured by slow tensile test (SSRT), and a strain rate of 2×10 -6 s -1 , the maximum stretching distance was measured in 3.5wt% NaCl aqueous solution.

[0105] Table 1 Performance test results

[0106]

[0107] It can be seen from Examples 1-2 that the aluminum alloy of the present invention has excellent mechanical properties and corrosion resistance. It can be seen from Comparative Examples 1-6 that the comprehensive properties of the aluminum alloy decrease to varying degrees by changing the composition and ratio of the aluminum alloy and the preparation process.

[0108] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A 7 series aluminum alloy communication tower profile, characterized in that: Including the following components in mass percentage: Zn 6.4-6.6%, Mn 0.2-0.4%, Mg 1.6-2.0%, Cu 0.3-0.4%, Si ≤ 0.15%, Fe ≤ 0.3%, Sc 0.2-0.3%, Er 0.1-0.2%, Cr 0.15-0.22%, Zr 0.1-0.2%, Ti ≤ 0.1%, other single impurity elements ≤ 0.05%, total impurity content ≤ 0.15%, and the balance is Al; The sum of the mass percentages of Sc, Er and Cr is ≤0.6%; The method for preparing the 7 series aluminum alloy communication pole tower profile is characterized by comprising the following steps: (1) Weigh the corresponding raw materials according to the composition of the aluminum alloy; (2) melting the prepared aluminum alloy raw material at 750-760°C and casting it into an aluminum alloy ingot; (3) subjecting the aluminum alloy ingot to a two-stage homogenization treatment; (4) Extruding the ingot after the double-stage homogenization treatment: the heating temperature of the aluminum alloy ingot is 450-470°C, the heating temperature of the extrusion barrel is 480-500°C, the extrusion ratio is 20:1, and the extrusion speed is 1.5-1.7 mm / min to obtain an aluminum alloy profile; (5) Online quenching of the aluminum alloy profile: the quenching method is spraying, the water temperature is 20-30°C, and the spraying speed is 15-20m / s; (6) performing a double-stage aging heat treatment on the quenched aluminum alloy profile, and air cooling to room temperature to obtain a 7 series aluminum alloy communication tower profile; The two-stage homogenization treatment is specifically: after keeping the temperature at 450-460°C for 8-10 hours, keep the temperature at 480-490°C for 16-18 hours; The steps of double-stage aging heat treatment are as follows: first-stage aging heat treatment: aging temperature is 100-105℃, and holding time is 10-12h; then the aging temperature of the aluminum alloy profile is returned to 200-210℃ within 20-30min and then quenched again, and then the second-stage aging heat treatment is performed: aging temperature is 150-155℃, and holding time is 15-17h.

2. A 7 series aluminum alloy communication tower profile according to claim 1, characterized in that: It includes the following components in mass percentage: Zn 6.5%, Mn 0.3%, Mg 1.8%, Cu 0.35%, Si 0.1%, Fe 0.15%, Sc 0.23%, Er 0.13%, Cr 0.18%, Zr 0.17%, Ti 0.05%, other single impurity elements ≤ 0.05%, total impurity content ≤ 0.15%, and the balance is Al.

3. A method for preparing the 7 series aluminum alloy communication tower profile according to any one of claims 1 to 2, characterized in that: The following steps are involved: (1) Weigh the corresponding raw materials according to the composition of the aluminum alloy; (2) melting the prepared aluminum alloy raw material at 750-760°C and casting it into an aluminum alloy ingot; (3) subjecting the aluminum alloy ingot to a two-stage homogenization treatment; (4) Extruding the ingot after the double-stage homogenization treatment: the heating temperature of the aluminum alloy ingot is 450-470°C, the heating temperature of the extrusion barrel is 480-500°C, the extrusion ratio is 20:1, and the extrusion speed is 1.5-1.7 mm / min to obtain an aluminum alloy profile; (5) Online quenching of the aluminum alloy profile: the quenching method is spraying, the water temperature is 20-30°C, and the spraying speed is 15-20m / s; (6) performing a double-stage aging heat treatment on the quenched aluminum alloy profile, and air cooling to room temperature to obtain a 7 series aluminum alloy communication tower profile; The two-stage homogenization treatment is specifically: after keeping the temperature at 450-460°C for 8-10 hours, keep the temperature at 480-490°C for 16-18 hours; The steps of double-stage aging heat treatment are as follows: first-stage aging heat treatment: aging temperature is 100-105℃, and holding time is 10-12h; then the aging temperature of the aluminum alloy profile is returned to 200-210℃ within 20-30min and then quenched again, and then the second-stage aging heat treatment is performed: aging temperature is 150-155℃, and holding time is 15-17h.

4. The preparation method according to claim 3, characterized in that: The second quenching method is spraying, the water temperature is 15-20℃, and the spraying speed is 10-15m / s.

5. The preparation method according to claim 3, characterized in that: The double-stage homogenization treatment is specifically: keeping the temperature at 455° C. for 9 hours and then keeping the temperature at 485° C. for 17 hours.

6. The preparation method according to claim 3, characterized in that: The heating temperature of the aluminum alloy ingot is 460° C., the heating temperature of the extrusion barrel is 490° C., the extrusion ratio is 20:1, the extrusion speed is 1.6 mm / min, and the aluminum alloy profile is obtained.

7. The preparation method according to claim 3, characterized in that: The steps of the double-stage aging heat treatment are as follows: the first stage aging heat treatment: the aging temperature is 102°C and the holding time is 11h; then the aging temperature of the aluminum alloy profile is returned to 205°C within 25min and then quenched, and then the second stage aging heat treatment is performed: the aging temperature is 153°C and the holding time is 16h.

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