Aluminum alloy monofilament for overhead transmission conductor and preparation method of aluminum alloy monofilament

Abstract

The invention discloses an aluminum alloy monofilament for an overhead transmission conductor and a preparation method of the aluminum alloy monofilament, and belongs to the technical field of electrical conductor materials, and the preparation method comprises the steps that ZrO2 powder, MgO powder and MoO3 powder are mixed and then treated to obtain ZrMgMo3O12 powder; industrial pure aluminum ingots are added into a smelting furnace, Al-Si and Al-Ce intermediate alloys are added after pure aluminum is completely melted, ZrMgMo3O12 powder obtained after stirring is pressed into the bottom of a solution, stirring is conducted after standing, and an aluminum alloy solution is obtained; argon is blown into the obtained aluminum alloy solution, and drossing is carried out after heat preservation and standing; the aluminum alloy solution is poured into a preheated metal mold, and aluminum ingots are formed through casting; the obtained aluminum ingot is rolled, and an aluminum alloy round rod is obtained; the obtained aluminum alloy round rod is subjected to multi-pass drawing, and a monofilament is obtained; and the obtained monofilament is subjected to heat preservation for 1-4 h at the temperature of 100-140 DEG C and then air cooling, and the aluminum alloy monofilament The conductivity of the prepared low-thermal-expansion aluminum alloy monofilament is larger than or equal to 55% IACS (20 DEG C), the tensile strength is larger than or equal to 160 MPa, the ductility is larger than or equal to 2.0%, and the thermal expansion coefficient is about 20 * 10 <-6 > / DEG C.

Description

Technical Field

[0001] The invention belongs to the technical field of electrical conductor materials, and in particular, relates to an aluminum alloy monofilament for an overhead power transmission line and a preparation method thereof. Background Art

[0002] Building a new power system with new energy as the main body and constructing safe and efficient transmission lines are major national needs. However, the existing transmission lines mainly use ordinary steel-core aluminum stranded wires, and the linear expansion coefficient of aluminum conductors is about 23×10 -6 / ℃, the linear expansion coefficient of ordinary steel core material is about 11×10 -6 / ℃, the difference between the two is large, resulting in the comprehensive linear expansion coefficient of ordinary steel-aluminum stranded wire reaching 20×10 -6 / ℃, the sag characteristics are poor and the safe distance to the ground is reduced.

[0003] At present, the research direction of overhead transmission lines focuses on the high strength of core wire materials and the high conductivity of conductor materials. There has been no systematic study on the matching correlation problem caused by the different linear expansion coefficients of the two under high-temperature service conditions.

[0004] Prior art document 1 (CN107881378B) discloses an aluminum alloy composition, an aluminum alloy component, a communication product and a method for preparing an aluminum alloy component, wherein the aluminum alloy composition comprises an aluminum main body and doping elements, wherein the doping elements comprise 18% to 22% Si, 0.2% to 0.95% Cu, 0.25% to 2% Fe, 0.05% to 0.2% Mg and 0.04% to 0.08% P, accounting for the total weight of the aluminum alloy composition. The combination of the elements in the above aluminum alloy composition enables the aluminum alloy component prepared from the aluminum alloy composition to have wear resistance, low thermal expansion coefficient and high thermal conductivity, but the Si mass fraction is high, the deformation processing ability is poor, and the electrical conductivity is poor.

[0005] Therefore, it is necessary to develop low expansion aluminum alloy conductor materials to ensure the safety and reliability of overhead transmission lines. Summary of the invention

[0006] In order to solve the deficiencies in the prior art, the present invention provides an Al-Si-Ce-ZrMgMo 3 O 12 Low thermal expansion aluminum alloy monofilament material solves the technical problem of large thermal expansion coefficient of existing aluminum alloy monofilament. It is mainly achieved by adding Si and negative thermal expansion ZrMgMo 3 O 12 Improve the alloy microstructure and comprehensive performance, develop a product with conductivity of 55% IACS (20℃), tensile strength of not less than 160MPa, elongation of not less than 2%, thermal expansion coefficient of less than 20×10-6 / K aluminum alloy monofilament.

[0007] The present invention adopts the following technical solution.

[0008] A first aspect of the present invention discloses an aluminum alloy monofilament for an overhead power transmission line.

[0009] The composition is calculated by mass percentage, including: Ce: 0.3-0.8%, Si: 2-5%, ZrMgMo 3 O 12 :2~5%, the rest is aluminum content and other inevitable trace impurities.

[0010] Preferably, the electrical conductivity of the aluminum alloy monofilament is ≥55% IACS, the tensile strength is ≥160 MPa, and the elongation is ≥2.0%.

[0011] A second aspect of the present invention discloses a method for preparing an aluminum alloy monofilament for an overhead power transmission line, comprising the following steps:

[0012] Sintering: ZrO 2 , MgO and MoO 3 The powders were mixed according to the set molar ratio, ball milled, sintered, and ball milled again to obtain ZrMgMo 3 O 12 powder;

[0013] Smelting: Add industrial pure aluminum ingots into the smelting furnace and smelt at the set temperature. After the pure aluminum is completely melted, add Al-Si and Al-Ce master alloys and stir to obtain ZrMgMo 3 O 12 The powder is pressed into the bottom of the solution, left to stand and then stirred to obtain an aluminum alloy solution;

[0014] Refining: At a set temperature, argon gas is blown into the obtained aluminum alloy solution, and the slag is removed after being kept still at the temperature;

[0015] Casting: Pour the aluminum alloy solution at a set temperature into a preheated metal mold to cast it into an aluminum ingot;

[0016] Rolling: rolling the obtained aluminum ingot to obtain aluminum alloy round rods;

[0017] Drawing: The obtained aluminum alloy round rod is drawn through multiple passes to obtain a single wire;

[0018] Annealing: The obtained single wire is kept at 100-140°C for 1-4 hours and then air-cooled to obtain the aluminum alloy single wire.

[0019] Preferably, the ZrO 2 , MgO and MoO 3The purity of the powder was 99.9% and the set molar ratio was 1:1:3.

[0020] Preferably, the ball milling time is 2 hours, the sintering temperature is 800° C., and the sintering time is 4 hours.

[0021] Preferably, the smelting specifically includes: selecting industrial pure aluminum ingots with a purity of ≥99.7% and adding them into a smelting furnace at a smelting temperature of 730-750°C; after the pure aluminum is completely melted, adding Al-Si and Al-Ce master alloys at 730-750°C, stirring for 10-15 minutes after complete melting, and keeping the temperature for 20-30 minutes. 3 O 12 The powder was pressed into the bottom of the solution and allowed to stand for 30 min before stirring.

[0022] Preferably, the refining specifically includes: blowing argon gas into the aluminum alloy solution at a temperature of 710-720° C. for 10-15 minutes, keeping the temperature at room temperature for 10-20 minutes, and then skimming the slag.

[0023] Preferably, the casting specifically includes: when the aluminum alloy solution is at 690-710° C., pouring the aluminum alloy solution into a metal mold preheated at 250-300° C., and casting it into an aluminum ingot with a cross-section of 20×20 mm.

[0024] Preferably, the rolling process specifically includes: keeping the aluminum ingot at 510-530°C for 1-3 hours and then rolling it, and rolling it into The aluminum alloy round rod is then kept at 300-350℃ for 20-40h.

[0025] Preferably, the drawing specifically includes: the aluminum alloy round rod is subjected to multiple drawing steps at 300-400°C to obtain Aluminum alloy monofilament.

[0026] Compared with the prior art, the beneficial effects of the present invention include at least:

[0027] Under the preparation process of the present invention, the thermal expansion coefficient of Si particles is low, and ZrMgMo 3 O 12 It is a negative thermal expansion material, adding Si, ZrMgMo 3 O 12 Ce forms high melting point compounds with impurity elements such as Fe and Si, which can reduce the solid solubility of Fe and Si in the alloy, refine the coarse micron-sized particles of AlFeSi and Si in the cast structure, and improve the mechanical properties and electrical conductivity of the alloy. At the same time, the addition of Ce can form Al after long-term annealing. 3 Ce phase improves the strength of the alloy and reduces the thermal expansion coefficient of the alloy by about 20×10-6 / ℃.

[0028] Through the reasonable matching of the composition formula and preparation process parameters of the patented invention, the low thermal expansion aluminum alloy single wire prepared has a conductivity of ≥55% IACS (20°C), a tensile strength of ≥160MPa, an elongation of ≥2.0%, and a thermal expansion coefficient of about 20×10 -6 / ℃, which is about 23×10 -6 / ℃ compared with the previous one, the thermal expansion coefficient is significantly reduced, thus reducing the sag length of the conductor under high temperature operating conditions, increasing the safe distance to the ground, and making the expansion coefficient of the aluminum alloy close to that of the super strong steel core, ensuring the safety and reliability of the transmission line under high temperature operating environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flow chart of the preparation method described in the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only embodiments of a part of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0031] The present invention aims to develop an Al-Si-Ce-ZrMgMo with an aluminum ingot having a purity of ≥99.7% as a raw material. 3 O 12 Low thermal expansion aluminum alloy monofilament material is used for overhead power transmission lines to solve the technical problem of large thermal expansion coefficient of existing aluminum alloy monofilament. It is mainly achieved by adding Si and negative thermal expansion ZrMgMo 3 O 12 Improve the alloy microstructure and comprehensive performance, develop a conductivity of 55% IACS (20 ° C), tensile strength not less than 160MPa, elongation not less than 2%, thermal expansion coefficient less than 20×10 -6 / K aluminum alloy monofilament.

[0032] The embodiment of the present invention provides a low thermal expansion coefficient Al-Si-Ce-ZrMgMo for overhead power transmission lines 3 O 12 Alloy monofilament, mainly including Si, ZrMgMo 3 O 12 The contents of each component are: Si: 2-5%, ZrMgMo 3 O 12:2-5%, Ce: 0.3-0.8%, the rest is aluminum content and other inevitable trace impurities.

[0033] The role and mechanism of each alloying element are as follows:

[0034] Cerium (Ce): The addition of Ce in the present invention can have a modifying effect on the microstructure and can effectively improve the morphology of the eutectic structure. On the one hand, these rare earth elements can form high-melting point compounds with Al, impurity elements Fe, Si, etc. During the solidification process, the high-melting point compounds are first precipitated, providing a large number of heterogeneous nucleation points; on the other hand, the rare earth elements are segregated at the solid-liquid interface, which can increase the composition fluctuations near the interface, increase the supercooling of the composition at the solid-liquid interface, and is conducive to non-spontaneous nucleation, thereby achieving the effect of grain refinement. At the same time, cerium can also refine the Si particles in the cast structure and change its morphology, which is conducive to improving the ductility of the alloy.

[0035] Silicon (Si): Silicon is one of the main impurity elements in industrial aluminum. Si has a low solid solubility in Al and does not form a compound with Al. It can exist in the form of single substance Si. Si has a low thermal expansion coefficient, generally 4.2×10 -6 K -1 , which can reduce the thermal expansion coefficient of aluminum alloy.

[0036] ZrMgMo 3 O 12 :It is a negative thermal expansion coefficient material with a thermal expansion coefficient of -373×10 -6 K -1 , and has good thermal stability. Adding it to Al alloy can reduce the thermal expansion coefficient of the alloy.

[0037] like Figure 1 As shown, an embodiment of the present invention also provides a method for preparing a low thermal expansion coefficient aluminum alloy single wire material, which specifically includes the following steps:

[0038] Step 1, sintering: ZrO 2 , MgO and MoO 3 The powders were mixed according to the set molar ratio, ball milled, sintered, and ball milled again to obtain ZrMgMo 3 O 12 powder;

[0039] In a preferred but non-limiting embodiment of the present invention, step 1 specifically comprises: ZrO with a purity of 99.9% 2 , MgO and MoO 3 The powders were mixed in a molar ratio of 1:1:3, ball-milled for 2 h, sintered at 800 °C for 4 h, and then ball-milled for another 2 h.

[0040] Step 2, smelting: add industrial pure aluminum ingots into the smelting furnace, smelt at the set temperature, add the intermediate alloy after the pure aluminum is completely melted, stir and mix the ZrMgMo obtained in step 1 3 O 12 The powder is pressed into the bottom of the solution, left to stand and then stirred to obtain an aluminum alloy solution;

[0041] In a preferred but non-limiting embodiment of the present invention, step 2 specifically includes: selecting an industrial pure aluminum ingot with a purity of ≥99.7% and adding it to a smelting furnace at a smelting temperature of 730-750°C; after the pure aluminum is completely melted, adding Al-Si and Al-Ce master alloys at 730-750°C, stirring for 10-15 minutes after complete melting, and keeping the temperature for 20-30 minutes. 3 O 12 The powder was pressed into the bottom of the solution, left to stand for 30 min, and then stirred;

[0042] Further preferably, the mass ratio of the Al-Si master alloy is Al-20Si; the mass ratio of the Al-Ce master alloy is Al-3Ce.

[0043] Step 3, refining: at a set temperature, blowing argon (Ar) into the aluminum alloy solution obtained in step 2, keeping the temperature and standing, and then skimming off the slag;

[0044] In a preferred but non-limiting embodiment of the present invention, step 3 specifically includes: when the aluminum alloy solution is 710-720°C, blowing argon (Ar) at a flow rate of 2L / h for 10-15min, keeping the temperature at room temperature for 10-20min and then skimming off the slag.

[0045] Step 4, casting: pouring aluminum alloy solution at a certain temperature into a preheated metal mold to cast into an aluminum ingot;

[0046] Step 4 specifically includes: when the aluminum alloy solution is at 690-710° C., pouring the aluminum alloy solution into a metal mold preheated at 250-300° C., and casting it into an aluminum ingot with a cross-section of 20×20 mm.

[0047] Step 5, rolling: rolling the aluminum ingot obtained in step 4 to obtain an aluminum alloy round rod;

[0048] Step 5 specifically includes: keeping the aluminum ingot at 510-530°C for 1-3 hours and then rolling it. The aluminum alloy round rod is then kept at 300-350℃ for 20-40h.

[0049] Step 6, drawing: the aluminum alloy round rod obtained in step 5 is subjected to multiple drawing passes to obtain an aluminum alloy monofilament;

[0050] Step 6 specifically includes: the aluminum alloy round rod is subjected to multiple drawing processes at 300-400°C to obtain Aluminum alloy monofilament.

[0051] Step 7, annealing: the single wire is kept at 100-140°C for 1-4 hours and then air-cooled to obtain a low expansion coefficient aluminum alloy single wire.

[0052] Example 1

[0053] A low thermal expansion coefficient aluminum alloy monofilament material, the components and their mass fractions are:

[0054]

[0055] (1) Sintering: ZrO with a purity of 99.9% 2 , MgO and MoO 3 The powders were mixed in a molar ratio of 1:1:3, ball-milled for 2 h, then sintered at 800 °C for 4 h, and then ball-milled for another 2 h;

[0056] (2) Smelting: Select industrial pure aluminum ingots with a purity of ≥99.7% and add them to the smelting furnace at a smelting temperature of 730°C; after the pure aluminum is completely melted, add Al-Si and Al-Ce master alloys at 750°C, stir for 15 minutes after complete melting, and keep warm for 20 minutes. 3 O 12 The powder was pressed into the bottom of the solution, left to stand for 30 min, and then stirred;

[0057] (3) Refining: Blow argon (Ar) at 710℃ for 15 min, keep at this temperature for 10 min and then skim off the slag;

[0058] (4) Casting: Pour the aluminum alloy liquid at 690°C into a metal mold preheated at 250°C to cast an aluminum ingot with a cross-section of 20×20 mm;

[0059] (5) Rolling: The aluminum ingot is kept at 510°C for 1 hour and then rolled. After 7 passes, it is rolled into a φ9.5 mm aluminum alloy round bar and then kept at 350°C for 20 hours;

[0060] (6) Drawing: The aluminum alloy round rod is drawn through multiple passes at 300°C to obtain φ3-4 mm aluminum alloy monofilament;

[0061] (7) Annealing: Keep the single wire at 100℃ for 1 to 4 hours and then air cool.

[0062] The aluminum alloy single wire prepared in this way has a conductivity of 55% IACS (20°C), a tensile strength of 160 MPa, an elongation of 2.0%, and a thermal expansion coefficient of 21×10 -6 / ℃.

[0063] Example 2

[0064] A low thermal expansion coefficient aluminum alloy monofilament material, the components and their mass fractions are:

[0065]

[0066] (1) Sintering: ZrO with a purity of 99.9% 2 , MgO and MoO 3 The powders were mixed in a molar ratio of 1:1:3, ball-milled for 2 h, then sintered at 800 °C for 4 h, and then ball-milled for another 2 h;

[0067] (2) Smelting: Select industrial pure aluminum ingots with a purity of ≥99.7% and add them to the smelting furnace at a smelting temperature of 730°C; after the pure aluminum is completely melted, add Al-Si and Al-Ce master alloys at 750°C, stir for 20 minutes after complete melting, and keep warm for 20 minutes. 3 O 12 The powder was pressed into the bottom of the solution, left to stand for 30 min, and then stirred;

[0068] (3) Refining: Blow argon (Ar) at 710℃ for 15 min, keep at this temperature for 10 min and then skim off the slag;

[0069] (4) Casting: Pour the aluminum alloy liquid at 690°C into a metal mold preheated at 250°C to cast an aluminum ingot with a cross-section of 20×20 mm;

[0070] (5) Rolling: The aluminum ingot is kept at 510°C for 3 hours and then rolled. After 7 passes, it is rolled into a φ9.5 mm aluminum alloy round bar and then kept at 350°C for 40 hours;

[0071] (6) Drawing: The aluminum alloy round rod is drawn through multiple passes at 300°C to obtain φ3-4 mm aluminum alloy monofilament;

[0072] (7) Annealing: The single filament is kept at 100°C for 2 h and then air-cooled.

[0073] The aluminum alloy single wire prepared in this way has a conductivity of 54% IACS (20°C), a tensile strength of 180 MPa, an elongation of 2.0%, and a thermal expansion coefficient of 20.5×10 -6 / ℃.

[0074] Example 3

[0075] A low thermal expansion coefficient aluminum alloy monofilament material, the components and their mass fractions are:

[0076]

[0077] (1) Sintering: ZrO with a purity of 99.9%2 , MgO and MoO 3 The powders were mixed in a molar ratio of 1:1:3, ball-milled for 2 h, then sintered at 800 °C for 4 h, and then ball-milled for another 2 h;

[0078] (2) Smelting: Select industrial pure aluminum ingots with a purity of ≥99.7% and add them to the smelting furnace at a smelting temperature of 730°C; after the pure aluminum is completely melted, add Al-Si and Al-Ce master alloys at 750°C, stir for 30 minutes after complete melting, and keep warm for 30 minutes. 3 O 12 The powder was pressed into the bottom of the solution, left to stand for 30 min, and then stirred;

[0079] (3) Refining: Blow argon (Ar) at 720°C for 15 min, keep at this temperature for 10 min and then skim off the slag;

[0080] (4) Casting: Pour the aluminum alloy liquid at 700°C into a metal mold preheated at 250°C to cast an aluminum ingot with a cross-section of 20×20 mm;

[0081] (5) Rolling: The aluminum ingot is kept at 520°C for 1 hour and then rolled. After 7 passes, it is rolled into a φ9.5 mm aluminum alloy round bar and then kept at 400°C for 20 hours;

[0082] (6) Drawing: The aluminum alloy round rod is drawn through multiple passes at 350°C to obtain φ3-4 mm aluminum alloy monofilament;

[0083] (7) Annealing: The single filament is kept at 140°C for 4 hours and then air-cooled.

[0084] The aluminum alloy single wire prepared in this way has a conductivity of 53.2% IACS (20°C), a tensile strength of 190 MPa, an elongation of 2.0%, and a thermal expansion coefficient of 19.9×10 -6 / ℃.

[0085] Example 4

[0086] A low thermal expansion coefficient aluminum alloy monofilament material, the components and their mass fractions are:

[0087]

[0088] (1) Sintering: ZrO with a purity of 99.9% 2 , MgO and MoO 3 The powders were mixed in a molar ratio of 1:1:3, ball-milled for 2 h, then sintered at 800 °C for 4 h, and then ball-milled for another 2 h;

[0089] (2) Smelting: Select industrial pure aluminum ingots with a purity of ≥99.7% and add them to the smelting furnace at a smelting temperature of 730°C; after the pure aluminum is completely melted, add Al-Si and Al-Ce master alloys at 750°C, stir for 50 minutes after complete melting, and keep warm for 30 minutes. 3 O 12 The powder was pressed into the bottom of the solution, left to stand for 30 min, and then stirred;

[0090] (3) Refining: Blow argon (Ar) at 720°C for 15 min, keep at this temperature for 10 min and then skim off the slag;

[0091] (4) Casting: Pour the aluminum alloy liquid at 710°C into a metal mold preheated at 250°C to cast an aluminum ingot with a cross-section of 20×20 mm;

[0092] (5) Rolling: The aluminum ingot is kept at 530°C for 2 hours and then rolled. After 7 passes, it is rolled into a φ9.5 mm aluminum alloy round bar and then kept at 350°C for 20 hours;

[0093] (6) Drawing: The aluminum alloy round rod is drawn through multiple passes at 350°C to obtain φ3-4 mm aluminum alloy monofilament;

[0094] (7) Annealing: The single filament is kept at 140°C for 4 hours and then air-cooled.

[0095] The aluminum alloy single wire prepared in this way has a conductivity of 52% IACS (20°C), a tensile strength of 198 MPa, an elongation of 2.0%, and a thermal expansion coefficient of 19.8×10-6 / °C.

[0096] Example 5

[0097] A low thermal expansion coefficient aluminum alloy monofilament material, the components and their mass fractions are:

[0098]

[0099]

[0100] (1) Sintering: ZrO with a purity of 99.9% 2 , MgO and MoO 3 The powders were mixed in a molar ratio of 1:1:3, ball-milled for 2 h, then sintered at 800 °C for 4 h, and then ball-milled for another 2 h;

[0101] (2) Smelting: Select industrial pure aluminum ingots with a purity of ≥99.7% and add them to the smelting furnace at a smelting temperature of 730°C; after the pure aluminum is completely melted, add Al-Si and Al-Ce master alloys at 750°C, stir for 50 minutes after complete melting, and keep the temperature for 50 minutes. 3 O12 The powder was pressed into the bottom of the solution, left to stand for 30 min, and then stirred;

[0102] (3) Refining: Blow argon (Ar) at 730°C for 20 min, keep at this temperature for 20 min and then skim off the slag;

[0103] (4) Casting: Pour the aluminum alloy liquid into a metal mold preheated at 300°C at 710°C to cast an aluminum ingot with a cross-section of 20×20 mm;

[0104] (5) Rolling: The aluminum ingot is kept at 530°C for 2 hours and then rolled. After 7 passes, it is rolled into a φ9.5 mm aluminum alloy round bar and then kept at 400°C for 20 hours;

[0105] (6) Drawing: The aluminum alloy round rod is drawn through multiple passes at 400°C to obtain φ3-4 mm aluminum alloy monofilament;

[0106] (7) Annealing: The single filament is kept at 140°C for 4 hours and then air-cooled.

[0107] The aluminum alloy single wire prepared in this way has a conductivity of 51.5% IACS (20°C), a tensile strength of 210 MPa, an elongation of 2.0%, and a thermal expansion coefficient of 19×10 -6 / ℃.

[0108] Compared with the prior art, the beneficial effects of the present invention include at least:

[0109] Under the preparation process of the present invention, the thermal expansion coefficient of Si particles is low, and ZrMgMo 3 O 12 It is a negative thermal expansion material, adding Si, ZrMgMo 3 O 12 Ce forms high melting point compounds with impurity elements such as Fe and Si, which can reduce the solid solubility of Fe and Si in the alloy, refine the coarse micron-sized particles of AlFeSi and Si in the cast structure, and improve the mechanical properties and electrical conductivity of the alloy. At the same time, the addition of Ce can form Al after long-term annealing. 3 Ce phase improves the strength of the alloy and reduces the thermal expansion coefficient of the alloy by about 20×10 -6 / ℃.

[0110] Through the reasonable matching of the composition formula and preparation process parameters of the patented invention, the low thermal expansion aluminum alloy single wire prepared has a conductivity of ≥55%IACS (20℃), a tensile strength of ≥160MPa, an elongation of ≥2.0%, and a thermal expansion coefficient of about 20×10 -6 / ℃, which reduces the sag length of the conductor under high temperature operating conditions, increases the safe distance to the ground, and makes the expansion coefficient of the aluminum alloy close to that of the super-strong steel core, ensuring the safety and reliability of the transmission line in high temperature operating environment.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. An aluminum alloy monofilament for an overhead power transmission line, characterized in that: The composition is calculated by mass percentage, including: Ce: 0.3-0.8%, Si: 2-5%, ZrMgMo3O 12 :2~5%, the rest is aluminum content and other inevitable trace impurities.

2. The aluminum alloy monofilament for overhead power transmission line according to claim 1, characterized in that: The electrical conductivity of the aluminum alloy monofilament is ≥55% IACS, the tensile strength is ≥160 MPa, and the elongation is ≥2.0%.

3. A method for preparing an aluminum alloy monofilament for an overhead power transmission line according to claim 1 or 2, characterized in that: The following steps are involved: Sintering: ZrO2, MgO and MoO3 powders are mixed according to the set molar ratio, ball milled, sintered, and ball milled again to obtain ZrMgMo3O 12 powder; Smelting: Add industrial pure aluminum ingots into the melting furnace and melt at the set temperature. After the pure aluminum is completely melted, add Al-Si and Al-Ce master alloys and stir to obtain ZrMgMo3O 12 The powder is pressed into the bottom of the solution, left to stand and then stirred to obtain an aluminum alloy solution; Refining: At a set temperature, argon gas is blown into the obtained aluminum alloy solution, and the slag is removed after being kept still at the temperature; Casting: Pour the aluminum alloy solution at a set temperature into a preheated metal mold to cast it into an aluminum ingot; Rolling: rolling the obtained aluminum ingot to obtain aluminum alloy round rods; Drawing: The obtained aluminum alloy round rod is drawn through multiple passes to obtain a single wire; Annealing: The obtained single wire is kept at 100-140°C for 1-4 hours and then air-cooled to obtain the aluminum alloy single wire.

4. The method for preparing an aluminum alloy monofilament for an overhead power transmission line according to claim 3, characterized in that: The purity of the ZrO2, MgO and MoO3 powders is 99.9%, and the molar ratio thereof is set to be 1:1:

3.

5. The method for preparing an aluminum alloy monofilament for an overhead power transmission line according to claim 3, characterized in that: The ball milling time is 2 hours, the sintering temperature is 800° C., and the sintering time is 4 hours.

6. The method for preparing an aluminum alloy monofilament for an overhead power transmission line according to claim 3, characterized in that: The smelting process specifically includes: selecting industrial pure aluminum ingots with a purity of ≥99.7% and adding them into a smelting furnace at a smelting temperature of 730-750°C; after the pure aluminum is completely melted, adding Al-Si and Al-Ce master alloys at 730-750°C, stirring for 10-15 minutes after complete melting, and keeping the temperature for 20-30 minutes. 12 The powder was pressed into the bottom of the solution and allowed to stand for 30 min before stirring.

7. The method for preparing an aluminum alloy monofilament for an overhead power transmission line according to claim 3, characterized in that: The refining specifically includes: blowing argon gas into the aluminum alloy solution at 710-720°C for 10-15 minutes, keeping the temperature at room temperature for 10-20 minutes, and then removing the slag.

8. The method for preparing an aluminum alloy monofilament for an overhead power transmission line according to claim 3, characterized in that: The casting specifically includes: when the aluminum alloy solution is at 690-710° C., pouring the aluminum alloy solution into a metal mold preheated at 250-300° C., and casting it into an aluminum ingot with a cross section of 20×20 mm.

9. The method for preparing an aluminum alloy monofilament for an overhead power transmission line according to claim 3, characterized in that: The rolling specifically includes: keeping the aluminum ingot at 510-530°C for 1-3 hours and then rolling it, and after 7 passes of rolling it into a φ9.5mm aluminum alloy round rod, keeping it at 300-350°C for 20-40 hours.

10. The method for preparing an aluminum alloy monofilament for an overhead power transmission line according to claim 3, characterized in that: Drawing specifically includes: the aluminum alloy round rod is subjected to multiple drawing processes at 300-400° C. to obtain φ3-4mm aluminum alloy monofilaments.

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