Preparation method of aluminum-copper-rare earth alloy

Abstract

The invention relates to a preparation method of an aluminum-copper-rare earth alloy, which comprises the following steps of: preparing and pretreating raw materials to ensure that the composition proportion is accurate; smelting and refining to remove impurities, so that the materials are fully dissolved and fused; forming and solidifying the alloy; and alloy heat treatment improves the alloy performance. According to the aluminum-copper-rare earth alloy grounding material, aluminum serves as a matrix, copper and trace rare earth elements are added, and the mechanical property, corrosion resistance and thermal stability of the alloy can be improved by adding the rare earth elements into the aluminum-copper alloy; compared with a galvanized steel material, the effective life cycle of the grounding grid can be greatly prolonged, the operation reliability is improved, and compared with a pure copper or copper-coated steel material, the material and construction cost of a grounding project can be reduced, and the energy consumption of electrical equipment can be reduced.

Description

Technical Field

[0001] The invention relates to the field of alloy preparation of metal materials, and in particular to a method for preparing an aluminum-copper rare earth alloy. Background Art

[0002] Grounding is an electrical safety measure that aims to reliably connect the metal casing or other conductive parts of electrical equipment to the earth to ensure the safety of equipment and personnel. Grounding materials are needed in the grounding process. When lightning or electrical faults occur, grounding materials can quickly conduct current to the earth. The better the conductivity of the grounding material, the smaller the grounding resistance, so that the current can be conducted to the earth more effectively. In addition, the grounding material needs to have good corrosion resistance and stability to ensure that there will be no performance degradation during long-term use.

[0003] Traditional grounding materials such as galvanized steel have a short effective life cycle in harsh soil environments during the use of the grounding grid. Pure copper or copper-clad steel materials have high density and weight, which not only affects construction efficiency but also increases project costs. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a method for preparing an aluminum-copper rare earth alloy to solve one or more problems in the prior art.

[0005] To achieve the above object, the technical solution of the present invention is as follows: A method for preparing an aluminum-copper rare earth alloy, the preparation method comprising the following steps: Raw material preparation and pretreatment to ensure accurate ingredient ratio; Melting and refining remove impurities to fully dissolve and fuse the materials; Alloy forming and solidification; Alloy heat treatment improves alloy properties.

[0006] Furthermore, in the raw material preparation, the raw materials include aluminum, copper and rare earth elements, wherein aluminum accounts for 70% to 90% of the total weight, rare earth elements account for 0.1% to 5% of the total weight, and the rest is copper.

[0007] Furthermore, the rare earth element is one or more lanthanide elements and yttrium, wherein if lanthanum and cerium exist simultaneously in the multiple lanthanide elements, lanthanum and cerium shall account for 0.1% to 2% of the total weight of the rare earth elements.

[0008] Furthermore, during the smelting, the smelting temperature is 700-800° C., and copper, aluminum and rare earth elements are added in sequence.

[0009] Furthermore, continuous stirring is required during the smelting process, and the stirring rate is 20 to 200 r / min.

[0010] Furthermore, the refining and impurity removal is achieved by introducing an inert gas into the smelting melt.

[0011] Furthermore, the alloy is formed by pouring the refined alloy liquid into a preheated mold for casting. During the casting process, the cooling rate of the alloy liquid is controlled to be 1-10°C / s.

[0012] Furthermore, the alloy heat treatment comprises the following steps: Annealing treatment to improve alloy plasticity and toughness; Aging treatment improves alloy strength and hardness.

[0013] Furthermore, during the annealing process, the annealing temperature is controlled at 300-500° C., and the annealing time is 1-4 hours. During the annealing process, the heating rate and the holding time also need to be controlled, the heating rate is controlled at 50-100° C., and the holding time is controlled at 1-4 hours.

[0014] Furthermore, during the aging treatment process, the temperature is controlled at 150-250°C and the treatment time is; during the aging treatment process, the heating rate, insulation time and cooling rate must also be controlled, the heating rate is 10-30°C / min, the insulation time is 6-12h, and the cooling rate is 1-10°C / min.

[0015] Compared with the prior art, the beneficial technical effects of the present invention are as follows: (I) The present invention designs an aluminum-copper rare earth alloy grounding material, with aluminum as the matrix and copper and trace rare earth elements added. The addition of rare earth elements to the aluminum-copper alloy can improve the mechanical properties, corrosion resistance and thermal stability of the alloy; compared with galvanized steel materials, the effective life cycle of the grounding grid can be greatly extended, and the operational reliability can be improved; compared with pure copper or copper-coated steel materials, the material and construction costs of the grounding project can be reduced, and the energy consumption of electrical equipment can be reduced.

[0016] (ii) The aluminum-copper rare earth alloy grounding material of the present invention has a lower density and weight. Compared with the traditional copper grounding rod, the aluminum-copper rare earth alloy grounding rod has a lower density and lighter weight, and is more convenient to install and carry. This reduces the weight burden and improves the construction efficiency for large-scale power equipment and projects. Through alloying treatment, it has excellent mechanical properties and thermal stability and can work in various harsh environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic flow chart of a method for preparing an aluminum-copper rare earth alloy according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the present invention clearer, the following is a further detailed description of the preparation method of an aluminum-copper rare earth alloy proposed by the present invention in combination with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings adopt a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, please refer to the accompanying drawings. It should be noted that the structure, proportion, size, etc. illustrated by the accompanying drawings of this specification are only used to match the content disclosed in the specification, so that people familiar with this technology can understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical substantive significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effect that the present invention can produce and the purpose that can be achieved, should still fall within the scope of the technical content disclosed by the present invention.

[0019] See also Figure 1 The preparation method of the aluminum-copper rare earth alloy of this embodiment comprises the following steps: Step 1: Raw material preparation and pretreatment to ensure accurate ingredient ratio.

[0020] In the preparation of raw materials, the raw materials include aluminum, copper and rare earth elements, of which aluminum accounts for 70% to 90% of the total weight, rare earth elements account for 0.1% to 5% of the total weight, and the rest is copper. The rare earth elements are one or more lanthanide elements and yttrium. If lanthanum and cerium exist simultaneously in multiple lanthanide elements, lanthanum and cerium must account for 0.1% to 2% of the total weight of rare earth elements. All raw materials must undergo strict chemical composition analysis and physical property tests before use to ensure that they meet production standards.

[0021] Rare earth elements can improve the strength, hardness and oxidation resistance of the alloy through the mechanism of solid solution strengthening or precipitation strengthening, and significantly improve the corrosion resistance of the alloy.

[0022] Furthermore, for some raw materials, if there are impurities such as oxide scale and oil stains, pretreatment such as acid washing, alkali washing or sandblasting is required to remove surface pollutants and improve smelting efficiency.

[0023] Step 2: Melting and refining to remove impurities so that the materials are fully dissolved and fused.

[0024] Before smelting, select appropriate smelting equipment according to the production scale and alloy composition characteristics, such as medium frequency induction melting furnace, vacuum melting furnace, etc.

[0025] The pretreated raw materials are then put into a smelting furnace for smelting. The key to the smelting process is to control the accuracy of temperature and component content. During smelting, the smelting temperature is 700-800°C to ensure that copper and aluminum are completely fused and rare earth elements are fully dissolved. Copper, aluminum and rare earth elements are added in sequence. Since copper has a higher melting point, copper can be added to the furnace first for smelting. After the copper is completely melted, aluminum with a lower melting point is added, and finally, easily oxidized rare earth elements are added to reduce burning and oxidation.

[0026] During the smelting process, continuous stirring is required to promote uniform distribution of elements. The stirring rate is 20-200 r / min. Preferably, in the early stage of smelting, it is controlled to 50-200 r / min, which can promote uniform distribution of metal elements, avoid segregation of rare earth elements and aggregation of oxides, and will not introduce too much gas due to excessive stirring. At the end of smelting, it is controlled to 20-50 r / min to reduce gas entrainment and promote slag removal. At the same time, an appropriate amount of flux such as sodium hexafluoroaluminate can be added to remove gas and inclusions in the melt.

[0027] Furthermore, after the smelting is completed, a refining and impurity removal treatment is performed. The refining and impurity removal is achieved by introducing an inert gas into the smelting melt, such as using an inert gas such as argon to purge, so as to further remove the gas and inclusions in the melt and improve the purity of the alloy.

[0028] Step 3: Alloy forming and solidification.

[0029] The alloy is formed by pouring the refined alloy liquid into a preheated mold for casting. The mold is selected according to the shape and size requirements of the product. The mold is preheated before casting to reduce thermal stress and avoid the occurrence of cracks and defects.

[0030] Furthermore, during the casting process, the cooling rate of the alloy liquid is controlled to be 1-10°C / s to obtain more balanced performance, more stable microstructure and improved electrical conductivity.

[0031] Furthermore, after the alloy is cooled and solidified in the mold, it is demolded when it is cooled to room temperature or close to room temperature.

[0032] Step 4: Heat treatment of alloy to improve alloy properties.

[0033] Step 4.1: Annealing to improve the plasticity and toughness of the alloy.

[0034] During the annealing process, the annealing temperature is controlled at 300-500°C, and the annealing time is 1-4 hours. During the annealing process, the heating rate and the holding time must also be controlled. The heating rate is controlled at 50-100°C to prevent the internal thermal stress from increasing due to excessive temperature difference. The holding time is controlled at 1-4 hours. The specific holding time is adjusted according to the workpiece size and performance requirements. For example, small-sized workpieces are kept warm for 1-2 hours, and thick-walled or large-sized workpieces are kept warm for 2-4 hours to eliminate casting stress and improve the plasticity and toughness of the alloy.

[0035] Step 4.2: Aging treatment to improve alloy strength and hardness.

[0036] During the aging treatment, the temperature is controlled at 150-250°C and the treatment time is; during the aging treatment, the heating rate, holding time and cooling rate must also be controlled. The heating rate is 10-30°C / min to prevent stress or structural defects caused by uneven temperature. The holding time is 6-12h and the cooling rate is 1-10°C / min, which is conducive to uniform precipitation of strengthening phases, reducing thermal stress, and helping to optimize toughness and corrosion resistance, and improve the strength and hardness of the alloy.

[0037] Preferably, according to the application requirements, the alloy can be subjected to surface treatments such as polishing, sandblasting, and anodizing to improve its aesthetics and corrosion resistance. The heat-treated alloy material is cut, processed, and assembled according to the design requirements. Finally, the product is subjected to mechanical property tests such as tensile tests, hardness tests, impact tests, etc., corrosion resistance tests such as salt spray tests, electrochemical corrosion tests, etc., and non-destructive tests such as ultrasonic testing and X-ray testing, etc., to confirm that it meets the design requirements and usage standards before being put into use.

[0038] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0039] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing an aluminum-copper rare earth alloy, characterized in that: The preparation method comprises the following steps: Raw material preparation and pretreatment to ensure accurate ingredient ratio; Melting and refining remove impurities to fully dissolve and fuse the materials; Alloy forming and solidification; Alloy heat treatment improves alloy properties.

2. The method for preparing an aluminum-copper rare earth alloy according to claim 1, characterized in that: In the raw material preparation, the raw materials include aluminum, copper and rare earth elements, among which aluminum accounts for 70% to 90% of the total weight, rare earth elements account for 0.1% to 5% of the total weight, and the rest is copper.

3. The method for preparing an aluminum-copper rare earth alloy according to claim 2, characterized in that: The rare earth elements are one or more lanthanide elements and yttrium. If lanthanum and cerium exist simultaneously in the multiple lanthanide elements, lanthanum and cerium should account for 0.1% to 2% of the total weight of the rare earth elements.

4. The method for preparing an aluminum-copper rare earth alloy according to claim 1, characterized in that: During the smelting, the smelting temperature is 700-800° C., and copper, aluminum and rare earth elements are added in sequence.

5. The method for preparing an aluminum-copper rare earth alloy according to claim 4, characterized in that: The smelting process requires continuous stirring at a rate of 20 to 200 r / min.

6. The method for preparing an aluminum-copper rare earth alloy according to claim 5, characterized in that: The refining and impurity removal is achieved by introducing an inert gas into the molten melt.

7. The method for preparing an aluminum-copper rare earth alloy according to claim 1, characterized in that: The alloy is formed by pouring the refined alloy liquid into a preheated mold for casting. During the casting process, the cooling rate of the alloy liquid is controlled to be 1-10°C / s.

8. The method for preparing an aluminum-copper rare earth alloy according to claim 1, characterized in that: The alloy heat treatment comprises the following steps: Annealing treatment to improve alloy plasticity and toughness; Aging treatment improves alloy strength and hardness.

9. The method for preparing an aluminum-copper rare earth alloy according to claim 8, characterized in that: During the annealing process, the annealing temperature is controlled at 300-500° C., and the annealing time is 1-4 hours. During the annealing process, the heating rate and the insulation time also need to be controlled, the heating rate is controlled at 50-100° C., and the insulation time is controlled at 1-4 hours.

10. The method for preparing an aluminum-copper rare earth alloy according to claim 9, characterized in that: During the aging treatment, the temperature is controlled at 150-250°C and the treatment time is; during the aging treatment, the heating rate, insulation time and cooling rate need to be controlled, the heating rate is 10-30°C / min, the insulation time is 6-12h, and the cooling rate is 1-10°C / min.

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