A corrosion-resistant aluminum alloy grounding material and its preparation process

Abstract

The present invention belongs to the technical field of aluminum alloys, and specifically relates to a corrosion-resistant aluminum alloy grounding material and a preparation process thereof. The preparation process comprises the following steps: (1) weighing the components of the aluminum alloy, wherein the aluminum alloy comprises the following components in weight percentage: Re 0.01-0.5%, Ce 0.05-0.27%, Mg 0.5-1.72%, Cu 0.01-5%, Si 0.05-3%, Zr 0.01-1%, Ti 0.01-0.5%, Mn 0.01-1.5%, and the balance being Al; (2) preparing a hot extrusion; (3) performing high-pressure sandblasting on the surface of the extrusion; (4) performing stress relief annealing heat treatment on the sandblasted aluminum alloy; and (5) performing surface anodization. The corrosion-resistant aluminum alloy grounding material prepared by the present invention has high corrosion resistance in the high-salinity and alkaline soil of the Huangguan area, and has excellent grounding performance and mechanical properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum alloys, and in particular relates to a corrosion-resistant aluminum alloy grounding material and a preparation process thereof. Background Art

[0002] As power grids increase their safety requirements for transmission lines, safe and robust power transmission and transformation technologies are becoming a key future development direction. This places higher demands on the corrosion resistance of grounding materials and the safety of grounding grids. Damage or failure of such buried equipment primarily stems from electrochemical corrosion in corrosive soil environments and corrosion caused by leakage currents during grid equipment operation. Soil corrosion causes oxides to form on the surface of buried materials, reducing their cross-sectional area or even fracturing them, resulting in poor grounding performance. This can lead to accidents, endangering equipment and personnel safety, and causing significant economic losses.

[0003] Currently, commonly used grounding materials include galvanized steel and pure copper. Galvanized steel, as a grounding material, typically experiences severe corrosion after only 8-10 years of operation. This is particularly true in the highly saline and alkaline soils of the Huangguan area, where it corrodes rapidly, requiring regular excavation, inspection, and modification based on the severity of the corrosion. This fails to meet the requirements for safe power system operation. Furthermore, excavation, inspection, and maintenance of the grounding grid require groundwork, which is costly and impacts the normal operation of equipment, making implementation difficult. Pure copper, with its excellent electrical conductivity and corrosion resistance, offers a long lifespan and high reliability as a grounding material. However, copper is a heavy metal, polluting the environment and is also relatively expensive.

[0004] Therefore, the research and development of key technologies to improve the corrosion resistance of grounding materials is of great significance for improving the corrosion resistance of transmission tower grounding grids and ensuring the stability of the grounding performance of the grounding grid. It is also a key problem that needs to be solved in the safe production of power transmission systems. Aluminum alloy is currently the most widely used lightweight metal. Its production and processing costs are relatively low, and aluminum alloy itself has good corrosion resistance and electrical conductivity. In addition, compared with traditional galvanized grounding flat steel and copper grounding bodies, aluminum alloy gold grounding materials are prepared using plastic processing methods and do not require surface treatment processes such as hot-dip galvanizing. This can effectively avoid heavy metal pollution of the soil and the discharge of wastewater and exhaust gas, and has a good environmental protection effect.

[0005] Chinese patent publication number CN111424198A discloses a corrosion-resistant aluminum alloy grounding material and its manufacturing method, comprising the following steps: batching (preparing the raw materials for each component); smelting (adding the raw materials sequentially to form a molten liquid); drawing the molten liquid to form a drawn cast rod; hot extrusion (hot extruding the drawn cast rod in an extruder to form a hot extrusion with a desired cross-section); shot peening (shot peening the hot extrusion); and oxidation (oxidation of the shot-peened hot extrusion in an incubator). The beneficial effects of this method include suppressing the formation of aluminum-copper theta phase, reducing costs, and avoiding heavy metal ion pollution caused by copper.

[0006] Chinese patent publication number CN117613576A discloses a new type of oxidation-resistant aluminum alloy rare earth grounding material. It is mainly obtained by adding Si and Mn to obtain a new type of aluminum-silicon-manganese alloy material, and the aluminum-silicon-manganese alloy material is modified by adding Cu, Fe, Mg, Ni, Zn, Ti and a small amount of Sn, Pb, Cr, Ca, V, rare earth elements, etc., thereby obtaining a new type of aluminum alloy rare earth grounding material with excellent electrical conductivity, good tensile strength and elongation, excellent oxidation resistance, low manufacturing cost, and environmental friendliness. It can well meet the needs of use in the complex and changing environment of grounding projects and is of great significance to ensuring the stable operation of the power system and the personal safety of personnel.

[0007] The corrosion resistance of the aluminum alloy grounding material in the existing technology cannot meet the use requirements in the high saline-alkali soil of the Huang irrigation area, and the mechanical properties and conductivity also need to be improved. Summary of the Invention

[0008] The purpose of the present invention is to provide a corrosion-resistant aluminum alloy grounding material and a preparation process thereof.

[0009] In order to achieve the above object, the present invention provides the following technical solutions:

[0010] A preparation process of a corrosion-resistant aluminum alloy grounding material comprises the following steps:

[0011] (1) Weigh the components of the aluminum alloy, which includes the following components in weight percentage: Re 0.01-0.5%, Ce 0.05-0.27%, Mg 0.5-1.72%, Cu 0.01-5%, Si 0.05-3%, Zr 0.01-1%, Ti 0.01-0.5%, Mn 0.01-1.5%, and the balance is Al;

[0012] (2) In an argon atmosphere, the components of the aluminum alloy are mixed and then smelted to form a molten liquid, which is then refined using argon. After the refining is completed, the molten liquid is cast to obtain a drawn cast rod, which is preheated and extruded in an extruder. After the extrusion is completed, the rod is cooled to form an extruded part;

[0013] (3) Perform high-pressure sandblasting on the surface of the extruded part and clean it after the sandblasting is completed;

[0014] (4) performing stress relief annealing heat treatment on the sandblasted aluminum alloy, and air cooling to room temperature to obtain an annealed aluminum alloy part;

[0015] (5) Surface anodizing: The annealed aluminum alloy parts are sequentially subjected to alkaline washing and acid washing to obtain pretreated aluminum alloy parts; the pretreated aluminum alloy parts are anodized to obtain corrosion-resistant aluminum alloy grounding body materials.

[0016] Furthermore, the aluminum alloy includes the following components in weight percentage: Re 0.33~0.42%, Ce 0.15-0.27%, Mg 1.21-1.72%, Cu 2.12~4.05%, Si 1.01-2.08%, Zr 0.14~0.23%, Ti 0.10-0.17%, Mn 0.23-0.87%, and the balance is Al.

[0017] Furthermore, the sum of the weight percentages of Re and Ce is less than the weight percentage of Mn.

[0018] Furthermore, the weight percentage ratio of Cu to Mg is (1.5~2.0):1.

[0019] Furthermore, the extrusion conditions in step (2) are as follows: the mold is preheated to 400-420°C, the extrusion temperature is 430-460°C, the extrusion ratio is 20-30:1, and the extrusion speed is 5-10 mm / s.

[0020] Furthermore, the sandblasting conditions are as follows: the sandblasting medium is white corundum, the particle size is 80-120 mesh, the sandblasting pressure is 0.5-0.8 MPa, the angle is 60-75°, the distance is 150-200 mm, the sandblasting time is 3-5 min, and the surface roughness Ra is controlled at 2.5-4.0 μm.

[0021] Furthermore, the conditions for the annealing heat treatment are: firstly heating to 280-290°C, keeping the temperature for 1-2 hours, and then continuing to heating to 320-330°C, keeping the temperature for 1-2 hours.

[0022] Furthermore, the specific conditions of anodization are: the electrolyte is 180~200g / L sulfuric acid, the temperature is 18~22℃, the current density is 1.5~2.0A / dm², the oxidation time is 30~50min, and the voltage is 15~20V.

[0023] Furthermore, the thickness of the anodized film is 5-10 μm.

[0024] The present invention also provides a corrosion-resistant aluminum alloy grounding material prepared by the preparation process.

[0025] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0026] 1. The present invention improves the corrosion resistance of the aluminum alloy by carefully selecting the components of the aluminum alloy and satisfying that the sum of the weight percentages of Re and Ce is less than the weight percentage of Mn, while satisfying that the weight percentage ratio of Cu to Mg is (1.5-2.0):1, thereby improving the mechanical properties and electrical conductivity of the material.

[0027] 2. The stress relief annealing heat treatment method of the present invention uses a gradient heat treatment method to improve the corrosion resistance, mechanical properties and electrical conductivity of the aluminum alloy grounding material. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Metallographic images of the aluminum alloy grounding electrode of the aluminum alloy grounding material prepared in Example 4, (a) edge, (b) core.

[0029] Figure 2 Schematic diagram of the geometric model of micro grounding grid with different grounding materials.

[0030] Figure 3 Schematic diagram of the on-site situation of micro grounding grids with different grounding materials.

[0031] Figure 4 These are pictures of the aluminum alloy grounding material before the corrosion experiment. From left to right: 1. Example 1; 2. Example 2; 3. Example 3; 4. Example 5; 5. Comparative Example 1; 6. Example 7; 7. Example 6; 8. Example 4; 9. Comparative Example 2.

[0032] Figure 5 These are pictures of aluminum alloy grounding material after corrosion testing, from left to right: 1. Example 1; 2. Example 2; 3. Example 3; 4. Example 5; 5. Comparative Example 1; 6. Example 7; 7. Example 6; 8. Example 4; 9. Comparative Example 2.

[0033] Figure 6 Metallographic images of the aluminum alloy grounding electrode of the aluminum alloy grounding material prepared in Example 1, (a) edge, (b) core.

[0034] Figure 7 Metallographic images of the aluminum alloy grounding electrode of the aluminum alloy grounding material prepared in Example 2, (a) edge, (b) core.

[0035] Figure 8 Metallographic images of the aluminum alloy grounding electrode of the aluminum alloy grounding material prepared in Example 3, (a) edge, (b) core.

[0036] Figure 9 Metallographic images of the aluminum alloy grounding electrode of the aluminum alloy grounding material prepared in Example 5, (a) edge, (b) core.

[0037] Figure 10 Metallographic images of the aluminum alloy grounding electrode of the aluminum alloy grounding material prepared in Example 6, (a) edge, (b) core.

[0038] Figure 11 Metallographic images of the aluminum alloy grounding electrode of the aluminum alloy grounding material prepared in Example 7, (a) edge, (b) core.

[0039] Figure 12 The following are comparison diagrams of different grounding materials before and after rust removal after accelerated corrosion test: (a) is sample 1 before rust removal; (b) is sample 1 after rust removal; (c) is sample 2 before rust removal; (d) is sample 2 after rust removal; (e) is sample 3 before rust removal; (f) is sample 3 after rust removal; (g) is sample 4 before rust removal; (h) is sample 4 after rust removal; (i) is sample 5 before rust removal; (j) is sample 5 after rust removal; (k) is sample 6 before rust removal; (l) is sample 6 after rust removal; (m) is sample 7 before rust removal; (n) is sample 7 after rust removal; (o) is sample 8 before rust removal; (p) is sample 8 after rust removal; (q) is sample 9 before rust removal; (r) is sample 9 after rust removal; (s) is sample 10 before rust removal; (t) is sample 10 after rust removal; (u) is sample 11 before rust removal; (v) is sample 11 after rust removal. DETAILED DESCRIPTION

[0040] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0041] Example 1

[0042] This embodiment provides a preparation process of a corrosion-resistant aluminum alloy grounding body material, comprising the following steps:

[0043] (1) Weigh the components of the aluminum alloy. The aluminum alloy includes the following components in weight percentage: Re 0.38%, Ce 0.20%, Mg 1.25%, Cu 2.12%, Si 1.2%, Zr 0.19%, Ti 0.12%, Mn 0.65%, and the balance is Al;

[0044] (2) In an argon atmosphere, the components of the aluminum alloy were mixed and melted at 730 ° C to form a molten liquid. Argon refining was performed with a flow rate of 0.4 L / min and a time of 12 min. After the refining, the molten liquid was cast with a cooling water flow of 25 L / min and an ingot casting speed of 70 mm / min to obtain a drawn cast rod. The drawn cast rod was preheated at 460 ° C for 5 h and extruded in an extruder. The mold was preheated to 410 ° C, the extrusion temperature was 450 ° C, the extrusion ratio was 25:1, and the extrusion speed was 8 mm / s. After the extrusion was completed, it was water-cooled online at a water temperature of 25 ° C to form an extruded part.

[0045] (3) The surface of the extruded part is treated by high-pressure sandblasting. The sandblasting medium is white corundum, the particle size is 80-120 mesh, the sandblasting pressure is 0.6 MPa, the angle is 60-75°, the distance is 170 mm, the sandblasting time is 4 min, and the surface roughness Ra is controlled at 3.0 μm. After the sandblasting is completed, the part is placed in a mixture of acetone and ethanol with a volume ratio of 1:1 for ultrasonic cleaning.

[0046] (4) The aluminum alloy after sandblasting is subjected to stress relief annealing heat treatment, first heating to 285 ° C, keeping the temperature for 1.5 hours, then continuing to heat to 325 ° C, keeping the temperature for 1.5 hours, furnace cooling to 200 ° C and air cooling to room temperature to obtain annealed aluminum alloy parts;

[0047] (5) Surface anodization: The annealed aluminum alloy parts were immersed in 50 g / L NaOH at 60 ° C for 3 min and washed with water; then immersed in 150 mL / L HNO3 at room temperature for 1 min to obtain pretreated aluminum alloy parts; the pretreated aluminum alloy parts were anodized under the following conditions: the electrolyte was 190 g / L sulfuric acid, the temperature was 20 ° C, the current density was 1.8 A / dm², the oxidation time was 40 min, the voltage was 18 V, and the film thickness was 8 μm to obtain a corrosion-resistant aluminum alloy grounding material.

[0048] Example 2

[0049] This embodiment provides a preparation process of a corrosion-resistant aluminum alloy grounding body material, comprising the following steps:

[0050] (1) Weigh the components of the aluminum alloy. The aluminum alloy includes the following components in weight percentage: The aluminum alloy includes the following components in weight percentage: Re 0.33%, Ce 0.27%, Mg 1.3%, Cu 2.5%, Si 1.01%, Zr 0.14%, Ti 0.17%, Mn 0.87%, and the balance is Al.

[0051] (2) In an argon atmosphere, the components of the aluminum alloy were mixed and melted at 720 ° C to form a molten liquid. Argon refining was performed with a flow rate of 0.5 L / min and a time of 10 min. After the refining, the molten liquid was cast with a cooling water flow rate of 30 L / min and an ingot casting speed of 60 mm / min to obtain a drawn cast rod. The drawn cast rod was preheated at 480 ° C for 4 h and extruded in an extruder. The mold was preheated to 420 ° C, the extrusion temperature was 430 ° C, the extrusion ratio was 30:1, and the extrusion speed was 7 mm / s. After the extrusion was completed, it was water-cooled online at a water temperature of 30 ° C to form an extruded part.

[0052] (3) The surface of the extruded part is treated by high-pressure sandblasting. The sandblasting medium is white corundum with a particle size of 80-120 mesh, the sandblasting pressure is 0.5 MPa, the angle is 75°, the distance is 150 mm, the sandblasting time is 5 min, and the surface roughness Ra is controlled at 2.5 μm. After the sandblasting is completed, the part is placed in a mixture of acetone and ethanol with a volume ratio of 1:1 for ultrasonic cleaning.

[0053] (4) The aluminum alloy after sandblasting is subjected to stress relief annealing heat treatment, first heating to 290 ° C, keeping the temperature for 1 hour, then continuing to heat to 330 ° C, keeping the temperature for 1 hour, furnace cooling to 200 ° C and air cooling to room temperature to obtain annealed aluminum alloy parts;

[0054] (5) Surface anodization: The annealed aluminum alloy parts were immersed in 50 g / L NaOH at 60 ° C for 3 min and washed with water; then immersed in 150 mL / L HNO3 at room temperature for 1 min to obtain pretreated aluminum alloy parts; the pretreated aluminum alloy parts were anodized under the following conditions: the electrolyte was 190 g / L sulfuric acid, the temperature was 20 ° C, the current density was 1.8 A / dm², the oxidation time was 40 min, the voltage was 18 V, and the film thickness was 8 μm to obtain a corrosion-resistant aluminum alloy grounding material.

[0055] Example 3

[0056] This embodiment provides a preparation process of a corrosion-resistant aluminum alloy grounding body material, comprising the following steps:

[0057] (1) Weigh the components of the aluminum alloy. The aluminum alloy includes the following components in weight percentage: The aluminum alloy includes the following components in weight percentage: Re 0.42%, Ce 0.15%, Mg 1.32%, Cu 2.64%, Si 1.52%, Zr 0.17%, Ti 0.14%, Mn 0.67%, and the balance is Al.

[0058] (2) In an argon atmosphere, the components of the aluminum alloy were mixed and smelted at 760°C to form a molten liquid. Argon refining was performed at a flow rate of 0.3 L / min for 15 min. After refining, the molten liquid was cast with a cooling water flow rate of 20 L / min and an ingot casting speed of 80 mm / min to obtain a drawn cast rod. The drawn cast rod was preheated at 450°C for 6 h and extruded in an extruder. The mold was preheated to 400°C, the extrusion temperature was 460°C, the extrusion ratio was 20:1, and the extrusion speed was 10 mm / s. After extrusion, it was water-cooled online at a water temperature of 20°C to form an extruded part.

[0059] (3) The surface of the extruded part is treated by high-pressure sandblasting. The sandblasting medium is white corundum with a particle size of 80-120 mesh, the sandblasting pressure is 0.8 MPa, the angle is 60°, the distance is 200 mm, the sandblasting time is 3 min, and the surface roughness Ra is controlled at 4.0 μm. After the sandblasting is completed, the part is placed in a mixture of acetone and ethanol with a volume ratio of 1:1 for ultrasonic cleaning.

[0060] (4) The aluminum alloy after sandblasting is subjected to stress relief annealing heat treatment, first heating to 280 ° C, keeping it warm for 2 hours, then continuing to heat to 320 ° C, keeping it warm for 2 hours, furnace cooling to 200 ° C and then air cooling to room temperature to obtain annealed aluminum alloy parts;

[0061] (5) Surface anodization: The annealed aluminum alloy parts were immersed in 50 g / L NaOH at 60 ° C for 3 min and washed with water; then immersed in 150 mL / L HNO3 at room temperature for 1 min to obtain pretreated aluminum alloy parts; the pretreated aluminum alloy parts were anodized under the following conditions: the electrolyte was 190 g / L sulfuric acid, the temperature was 20 ° C, the current density was 1.8 A / dm², the oxidation time was 40 min, the voltage was 18 V, and the film thickness was 8 μm to obtain a corrosion-resistant aluminum alloy grounding material.

[0062] Example 4

[0063] This embodiment provides a preparation process of a corrosion-resistant aluminum alloy grounding body material, comprising the following steps:

[0064] (1) Weigh the components of the aluminum alloy. The aluminum alloy includes the following components in weight percentage: The aluminum alloy includes the following components in weight percentage: Re 0.42%, Ce 0.15%, Mg 1.72%, Cu 2.58%, Si 2.08%, Zr 0.14%, Ti 0.17%, Mn 0.77%, and the balance is Al.

[0065] (2) In an argon atmosphere, the components of the aluminum alloy were mixed and melted at 720 ° C to form a molten liquid. Argon refining was performed with a flow rate of 0.3 L / min and a time of 10 min. After the refining, the molten liquid was cast with a cooling water flow of 20 L / min and an ingot casting speed of 60 mm / min to obtain a drawn cast rod. The drawn cast rod was preheated at 450 ° C for 4 h and extruded in an extruder. The mold was preheated to 400 ° C, the extrusion temperature was 430 ° C, the extrusion ratio was 20:1, and the extrusion speed was 5 mm / s. After the extrusion was completed, it was water-cooled online at a water temperature of 20 ° C to form an extruded part.

[0066] (3) The surface of the extruded part is treated by high-pressure sandblasting. The sandblasting medium is white corundum with a particle size of 80-120 mesh, the sandblasting pressure is 0.8 MPa, the angle is 75°, the distance is 200 mm, the sandblasting time is 5 min, and the surface roughness Ra is controlled at 3.5 μm. After the sandblasting is completed, the part is placed in a mixture of acetone and ethanol with a volume ratio of 1:1 for ultrasonic cleaning.

[0067] (4) The aluminum alloy after sandblasting is subjected to stress relief annealing heat treatment, first heating to 290 ° C, keeping warm for 2 hours, then continuing to heat to 320 ° C, keeping warm for 1 hour, furnace cooling to 200 ° C and air cooling to room temperature to obtain annealed aluminum alloy parts;

[0068] (5) Surface anodization: The annealed aluminum alloy parts were immersed in 50 g / L NaOH at 60 ° C for 3 min and washed with water; then immersed in 150 mL / L HNO3 at room temperature for 1 min to obtain pretreated aluminum alloy parts; the pretreated aluminum alloy parts were anodized under the following conditions: the electrolyte was 190 g / L sulfuric acid, the temperature was 20 ° C, the current density was 1.8 A / dm², the oxidation time was 40 min, the voltage was 18 V, and the film thickness was 8 μm to obtain a corrosion-resistant aluminum alloy grounding material.

[0069] Example 5

[0070] The difference between this embodiment and embodiment 1 is that the aluminum alloy includes the following components in weight percentage: Re 0.2%, Ce 0.1%, Mg 1.0%, Cu 0.2%, Si 2.5%, Zr 0.5%, Ti 0.4%, Mn 0.7%, and the balance is Al.

[0071] Example 6

[0072] The difference between this embodiment and embodiment 4 is that the aluminum alloy includes the following components in weight percentage: Re 0.42%, Ce 0.15%, Mg 1.22%, Cu 3.08%, Si 2.08%, Zr 0.14%, Ti 0.17%, Mn 0.77%, and the balance is Al.

[0073] Example 7

[0074] The difference between this embodiment and embodiment 4 is that the aluminum alloy includes the following components in weight percentage: Re 0.47%, Ce 0.25%, Mg 1.72%, Cu 2.58%, Si 2.08%, Zr 0.14%, Ti 0.17%, Mn 0.52%, and the balance is Al.

[0075] Comparative Example 1

[0076] The difference between this comparative example and Example 1 is that the aluminum alloy includes the following components in weight percentage: Re 0.77%, Ce 1.55%, Mg 2.72%, Cu 1.58%, Si 1.08%, Zr 1.14%, Ti 0.67%, Mn 0.72%, and the balance is Al.

[0077] Comparative Example 2

[0078] The difference between this comparative example and Example 1 is that the aluminum alloy after sandblasting is subjected to stress relief annealing heat treatment, the temperature is raised to 300°C, kept warm for 3 hours, furnace cooled to 200°C and then air cooled to room temperature to obtain an annealed aluminum alloy part.

[0079] Performance Testing

[0080] 1. According to the requirements of GB / T 228.1-2021 “Tensile testing of metallic materials - Part 1: Room temperature test method”, samples of the aluminum alloy grounding materials prepared in Examples 1-7 and Comparative Examples 1-2 were subjected to room temperature tensile tests on a CMT5305 electronic universal testing machine.

[0081] 2. According to the requirements of GB / T 3048.4-2007 "Test methods for electrical properties of wires and cables - Part 4: DC resistance test for conductors", DC resistance tests were performed on the aluminum alloy grounding bodies of Examples 1-7 and Comparative Examples 1-2 on a QJ36B-2 digital bridge. The length of the grounding bodies used in the tests was 1 m, and the experimental temperature was 20°C.

[0082] 3. Corrosion Resistance Test: For the soil corrosion simulation solution test, 40L of soil corrosion simulation solution was prepared using 600g of analytically pure sodium chloride, 400g of sodium sulfate, 400g of sodium bicarbonate, 400g of calcium chloride, and 120g of magnesium chloride with deionized distilled water. Sodium chloride, calcium chloride, and magnesium chloride were used to control the chloride ion content, sodium sulfate to control the sulfate ion content, and sodium bicarbonate to control the carbonate ion content. The pH value of the solution was adjusted to approximately 8.5 using sodium hydroxide, thereby obtaining a simulated solution that was close to the soil corrosion characteristics of the Huang Irrigation Area. Throughout the test, a heating rod was used to heat the solution at a temperature of 50±5°C, and an oxygen pump was used to oxygenate the solution to intensify the corrosion process of the grounding material. To prevent changes in the concentration of the corrosion solution due to water evaporation, distilled water was regularly added to the solution during the test to maintain the volume of the soil corrosion simulation solution at approximately 40L. The cross-sectional dimensions of the samples were all 50 mm×5 mm, the test period was 100 days, and the corrosion conditions of the aluminum alloy grounding materials of Examples 1-7 and Comparative Examples 1-2 were recorded.

[0083] All samples before and after corrosion pictures are shown in Figure 4-5 , the results are shown in Table 1.

[0084] Table 1 Performance test results

[0085]

[0086] As can be seen from Table 1, the corrosion-resistant aluminum alloy grounding body materials of Examples 1-7 have high mechanical properties and electrical conductivity, especially Example 4 has better comprehensive performance and the most excellent corrosion resistance.

[0087] It can be found from Examples 5-7 that there is a synergistic effect between the components of the aluminum alloy. When the sum of the weight percentages of Re and Ce is less than the weight percentage of Mn, the corrosion resistance of the aluminum alloy can be improved. At the same time, when the weight percentage ratio of Cu and Mg is (1.5~2.0):1, the mechanical properties and conductivity of the material can be improved.

[0088] In Comparative Example 1, the composition ratio of the aluminum alloy grounding material was changed, the mechanical properties decreased, and the resistance value increased. In Comparative Example 2, the stress relief annealing heat treatment method was not performed, and the mechanical properties and conductivity of the aluminum alloy grounding material deteriorated.

[0089] 2. Accelerated Soil Corrosion Test: Taking into account the physical and chemical properties of soil from the Huang Irrigation Area, 230 kg of raw soil from the Huang Irrigation Area (pH = 8.89, weakly alkaline) was collected, crushed (200 mesh), and dried. The soil was then mixed evenly with 400 g of sodium chloride, 300 g of sodium sulfate, 300 g of sodium bicarbonate, 100 g of magnesium chloride, 100 g of calcium chloride, and 5 L of distilled water to create accelerated corrosion soil. The soil was placed in a plastic box, and the pH of the soil was adjusted to approximately 9.0 using sodium hydroxide. The soil temperature was maintained at 20 ± 5°C, and the air temperature at 20 ± 5°C. The grounding material of Example 4 and a commercially available grounding material were placed horizontally in a soil accelerated corrosion chamber. The chamber was replenished with 2 L of distilled water every 15 days to ensure relative stability of the soil moisture content. All grounding material specimens used in the accelerated corrosion tests were 50 mm × 50 mm × 5 mm. To ensure the accuracy and stability of the accelerated corrosion tests and minimize experimental error, three replicate samples were taken for each grounding material.

[0090] To more realistically reflect the corrosion of the grounding material, specimens were buried 15 cm from the soil surface, with a minimum spacing of 10 cm between specimens. The soil accelerated corrosion test cycle lasted 65 days. After 65 days, the grounding material corrosion specimens were removed and the grounding materials, which contained corrosion products, were derusted according to GB / T 16545-2015, "Corrosion of Metals and Alloys - Removal of Corrosion Products from Corrosion Test Specimens." After derusting, the specimens were placed in an oven to dry for 24 hours and weighed using an electronic balance with an accuracy of 1 part per 10,000. The corrosion rates of the different grounding materials in the soil accelerated corrosion chamber were then calculated based on the initial weight and sample surface area.

[0091] The results are shown in Table 2 and Figure 12 .

[0092] Table 2 Results of soil accelerated corrosion tests on different grounding materials

[0093]

[0094] Specific test data are shown in Table 2 and Figure 12The results show that the grounding materials used in the test exhibited varying degrees of corrosion. Carbon steel and galvanized steel specimens exhibited the most severe corrosion, with a dark brown surface and a layer of sand adhering to uneven thickness in some areas. The galvanized steel specimens had completely lost their protective coating, resulting in similar corrosion rates. The pure copper specimens exhibited a brownish color over most of the surface, with spotted green corrosion products visible in some areas. Numerous tiny pitting corrosion pits were present on the surface, but overall corrosion was mild. Untreated aluminum-copper-titanium specimens exhibited a small number of pits due to stress corrosion, with minor material delamination within the pits. Some pits were up to 2 mm in diameter, and the corrosion products were white powdery. The aluminum alloy specimens, which had been sandblasted and heat treated only, exhibited corrosion rates comparable to those of the untreated specimens. However, no significant pitting corrosion or material delamination was observed, and overall corrosion was relatively uniform. This suggests that sandblasting and heat treatment processes effectively improve the internal stress state of the aluminum alloy, significantly reducing its tendency to stress corrosion and preventing the formation of large pitting corrosion pits. The aluminum-copper-titanium samples that were only anodized showed less corrosion, with no obvious pitting. The corrosion rate was only half that of the unanodized samples, and close to the corrosion rate of pure copper, indicating that the anodic oxide film can effectively isolate the outside air, moisture, and corrosive media from contact, significantly improving the corrosion resistance of the aluminum alloy. The aluminum alloy grounding material prepared in Example 4, which was sandblasted, heat treated, and anodized simultaneously, showed the best corrosion resistance among all aluminum alloy grounding materials. Its corrosion rate was 1 / 85 and 1 / 20 of that of the commonly used grounding materials galvanized steel and pure copper, respectively. It is close to the corrosion resistance of stainless steel, effectively preventing the problem of premature failure of the grounding body due to corrosion.

[0095] 3. On-site grounding resistance test of high-performance corrosion-resistant aluminum alloy micro grounding grid

[0096] In order to study the corrosion resistance and grounding performance of grounding materials with different materials and surface treatment conditions in a real service environment, the present invention uses a welding method to process Example 4 with a specification of 50mm×5mm and commercially available grounding materials into a 1.5m×1.5m micro grounding grid, while ensuring that the vertical down conductor length of the grounding grid is 1m. Figure 2 and 3 To avoid mutual influence between micro-grounding grids made of different grounding materials, the spacing between different grounding grids is no less than 15m. At the same time, the grounding resistance of the grounding grid is regularly tested using the three-electrode method at a distance of 0.8m from the ground. The test data are shown in Table 3.

[0097] Table 3 Field test results of micro grounding grids with different grounding materials

[0098]

[0099] The test results show that the grounding resistance values ​​of micro-grounding grids made of different grounding materials are all below 2Ω, with similar values. Fluctuations in grounding resistance values ​​for different grounding materials are likely due to instrument and test errors. Furthermore, sandblasting effectively improves the surface roughness of the grounding element, increasing the contact area between the grounding element and the soil to a certain extent, thus promoting the grounding performance of the grounding grid.

[0100] The soil in the Huanggan irrigation area contains large amounts of chloride and sulfate. Dissolving these salts produces numerous ions, which serve as the primary carriers of current in the soil. The higher the salt content, the lower the soil resistivity. Furthermore, the soil also contains a high amount of water. As a good conductor, water provides a continuous conductive path for ion migration, increasing soil conductivity and reducing soil resistivity. Therefore, in the Huanggan irrigation area, where soil resistivity is low, corrosion resistance should be a priority when selecting grounding materials for power transmission and transformation equipment.

[0101] 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 within the scope of protection of the present invention.

Claims

1. A preparation process of a corrosion-resistant aluminum alloy grounding material, characterized in that: The following steps are involved: (1) Weigh the components of the aluminum alloy, which include the following components in weight percentage: Re 0.33-0.42%, Ce 0.15-0.27%, Mg 1.21-1.72%, Cu 2.12-4.05%, Si 1.01-2.08%, Zr 0.14-0.23%, Ti 0.10-0.17%, Mn 0.23-0.87%, and the balance is Al; The sum of the weight percentages of Re and Ce is less than the weight percentage of Mn; The weight percentage ratio of Cu and Mg is (1.5~2.0):1; (2) In an argon atmosphere, the components of the aluminum alloy are mixed and then smelted to form a molten liquid, which is then refined using argon. After the refining is completed, the aluminum alloy is cast to obtain a drawn cast rod, which is then extruded in an extruder to form an extruded part; (3) Perform high-pressure sandblasting on the surface of the extruded part; (4) The aluminum alloy after sandblasting is subjected to stress relief annealing heat treatment and air-cooled to room temperature to obtain annealed aluminum alloy parts; the annealing heat treatment conditions are: first heating to 280~290℃, keeping warm for 1~2h, then continuing to heat to 320~330℃, keeping warm for 1~2h; (5) Surface anodizing: Anodize the annealed aluminum alloy parts to obtain corrosion-resistant aluminum alloy grounding material.

2. The preparation process of the corrosion-resistant aluminum alloy grounding material according to claim 1, characterized in that: The extrusion conditions in step (2) are as follows: the mold is preheated to 400-420°C, the extrusion temperature is 430-460°C, the extrusion ratio is 20-30:1, and the extrusion speed is 5-10 mm / s.

3. The preparation process of the corrosion-resistant aluminum alloy grounding material according to claim 1, characterized in that: The conditions for sandblasting are as follows: the sandblasting medium is white corundum, the particle size is 80~120 mesh, the sandblasting pressure is 0.5~0.8MPa, the angle is 60~75°, the distance is 150~200mm, the sandblasting time is 3~5min, and the surface roughness Ra is controlled at 2.5~4.0μm.

4. The preparation process of the corrosion-resistant aluminum alloy grounding material according to claim 1, characterized in that: The specific conditions for anodization are: the electrolyte is 180~200g / L sulfuric acid, the temperature is 18~22℃, the current density is 1.5~2.0A / dm², the oxidation time is 30~50min, and the voltage is 15~20V.

5. The preparation process of the corrosion-resistant aluminum alloy grounding material according to claim 4, characterized in that: The thickness of the anodic oxide film is 5~10μm.

6. A corrosion-resistant aluminum alloy grounding material produced by the preparation process according to any one of claims 1 to 5.

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