High-conductivity super-heat-resistant aluminum alloy wire and preparation method thereof

Abstract

The invention discloses a high-conductivity super-heat-resistant aluminum alloy wire and a preparation method thereof, and the high-conductivity super-heat-resistant aluminum alloy wire comprises the following chemical components in percentage by mass: 2.0-2.5% of Ce and the balance of Al, the method comprises the following steps: firstly, carrying out gas-assisted continuous casting extrusion to obtain an alloy rod which contains alpha-Al with extremely low Ce solid solubility and an All1Ce3 phase with a small size, and then carrying out drawing and annealing treatment; by adding a small amount of Ce and combining gas-assisted continuous casting extrusion and annealing, the aluminum alloy wire has excellent strength, conductivity and heat resistance. The super-heat-resistant aluminum alloy wire prepared by the invention has relatively high conductivity, and the loss rate of a line during operation can be remarkably reduced.

Description

Technical Field

[0001] The invention relates to a high-conductivity super-heat-resistant aluminum alloy wire and a preparation method thereof, belonging to the technical field of wire and cable preparation. Background Art

[0002] Al-Zr super-heat-resistant aluminum alloy wire has a maximum allowable continuous operating temperature above 210°C and a transmission capacity twice that of ordinary duralumin wire. It has broad application prospects in areas such as capacity expansion and reconstruction of existing transmission corridors and high-capacity line construction. However, to force the Zr element into solid solution and then precipitate it, the alloy typically requires a long heat treatment (>100 hours), resulting in high production costs and hindering its widespread application.

[0003] To address this issue, patent CN202510033495.6 proposes a low-cost method for preparing ultra-heat-resistant aluminum alloy wire monofilaments. This method involves alloy smelting, gas-assisted continuous casting and extrusion, and drawing to produce an Al-Fe alloy wire containing a nanoscale iron-rich phase. This method eliminates the need for lengthy heat treatment and offers advantages such as low raw material costs, a short production process, and low energy consumption, thus possessing significant practical value. However, it is worth noting that the high cooling rate of the alloy melt during gas-assisted continuous casting and extrusion increases the solid solubility of Fe in the aluminum matrix. This higher solid solubility increases the probability of electron scattering, resulting in a higher line loss rate during operation. Therefore, the development of a low-cost, ultra-heat-resistant aluminum alloy wire with high conductivity has become a pressing matter. Summary of the Invention

[0004] The object of the present invention is to provide a high-conductivity super-heat-resistant aluminum alloy wire, wherein the chemical composition of the high-conductivity super-heat-resistant aluminum alloy wire is as follows: Ce 2.0-2.5% and the balance is Al, calculated by mass percentage.

[0005] Another object of the present invention is to provide a method for preparing a high-conductivity superheat-resistant aluminum alloy wire, which comprises: material preparation, smelting, gas-assisted continuous casting and extrusion, drawing, and annealing to obtain the alloy wire, specifically comprising the following steps:

[0006] (1) Material preparation: Al-Ce master alloy and high-purity aluminum ingot were weighed according to their chemical compositions.

[0007] (2) Melting: Place the Al-Ce master alloy and high-purity aluminum ingot into a furnace and melt them. Stir until the mixture is uniform. During the stirring process, the melt temperature is maintained at 770-780°C. Finally, keep the temperature at 730-740°C for 60 minutes.

[0008] (3) Al-Ce alloy rods were prepared by gas-assisted continuous casting and extrusion.

[0009] (4) The alloy rod obtained in step (3) is cold drawn to obtain a wire.

[0010] (5) Annealing the wire obtained in step (4) to obtain a high-conductivity super-heat-resistant aluminum alloy wire.

[0011] Preferably, the diameter of the funnel in step (3) of the present invention is 2.0-2.8 mm, and the funnel needs to be heated to 780-800° C. before pouring the alloy melt.

[0012] Preferably, the inert gas in step (3) of the present invention is nitrogen, argon, etc., and the gas pressure is 0.2-0.3 MPa.

[0013] Preferably, the speed of the extrusion wheel in step (3) of the present invention is 8-12 rpm.

[0014] Preferably, in step (3) of the present invention, the preheating temperature of the extrusion die cavity is 300-350° C., and the die hole diameter is 9.5 mm.

[0015] Preferably, in step (4) of the present invention, the cold drawing is performed for 4-6 times, and the total deformation is 70-80%.

[0016] Preferably, the annealing temperature in step (5) of the present invention is 175-200° C., and the annealing time is 1 hour.

[0017] Beneficial effects of the present invention:

[0018] The present invention adds a small amount of Ce and combines gas-assisted continuous casting and annealing to make the aluminum alloy wire have excellent strength, electrical conductivity and heat resistance.

[0019] (1) Small size α-Al and Al 11 Ce3 phase is beneficial to improving alloy strength: the high cooling rate during gas-assisted continuous casting can refine α-Al and Al l1 Ce3 phase improves the alloy strength through grain boundary strengthening and dispersion strengthening respectively.

[0020] (2) During the gas-assisted continuous casting process, the solid solubility of Ce in the aluminum matrix can still be maintained at an extremely low level, thereby obtaining a higher conductivity; in addition, the reduction of dislocation density in the wire after annealing can further reduce the scattering probability of electrons and improve the conductivity.

[0021] (3)Al 11 The excellent high temperature stability of Ce3 phase can ensure heat resistance: Ce has extremely low solid solubility and diffusion coefficient in aluminum, which makes the Al in the alloy 11 The Ce3 phase has a stable morphology below 300°C and can fully meet the test of super heat-resistant wires at 280°C / 1h.

[0022] (4) The Al-Ce alloy wire prepared by the present invention has an electrical conductivity of more than 61.0% IACS at 20°C and a tensile strength of more than 160 MPa. At the same time, after heat exposure at 280°C / 1h, the tensile strength retention rate can reach more than 90%, which fully meets the requirements of current standards for super heat-resistant aluminum alloy wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The following is a flow chart for preparing high-conductivity super-heat-resistant aluminum alloy wire;

[0024] Figure 2 This is the principle diagram of gas-assisted continuous casting and extrusion.

[0025] In the figure: 1-funnel; 2-metal melt; 3-extrusion wheel; 4-extrusion wheel groove; 5-mold cavity; 6-mold; 7-alloy rod; 8-injection device. DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0027] The device used in the embodiment of the present invention is as follows Figure 2 As shown, it includes a funnel 1, a metal melt 2, an extrusion wheel 3, an extrusion wheel groove 4, a die cavity 5, a die 6, an alloy rod 7, and an air jet device 8; the smelted metal melt 2 flows out from the preheated funnel 1 located above the extrusion wheel 3 to the extrusion wheel groove 4, and the air jet device 8 above the extrusion wheel groove 4 sprays inert gas. Under the action of the inert gas, the metal melt 2 spreads out closely against the wall of the extrusion wheel groove 4 and begins to solidify. Under the action of the rotation of the extrusion wheel 3 and the plug on the die cavity 5, the solidified billet is continuously extruded from the die 6 to obtain the alloy rod 7.

[0028] Example 1

[0029] The present invention relates to a high-conductivity super-heat-resistant aluminum alloy wire and a preparation method thereof, comprising the following steps:

[0030] (1) Material preparation: Weigh Al-Ce master alloy and high-purity aluminum ingots according to the mass percentage of Ce: 2.0% and the balance of Al.

[0031] (2) Melting: Al-Ce master alloy and high-purity aluminum ingots are placed in a furnace for melting and stirred until uniformly mixed. The melt temperature is maintained at 770°C during the stirring process. Finally, the melt temperature is maintained at 730°C for 60 minutes to complete the melting.

[0032] (3) Preparation of Al-Ce alloy rods by gas-assisted continuous casting and extrusion: the molten alloy melt flows out from a funnel located above the extrusion wheel groove (the funnel diameter is 2.8 mm), and an inert gas (nitrogen gas, gas pressure is 0.30 MPa) is sprayed above the extrusion wheel groove. Under the combined action of gravity and the inert gas jet, the alloy melt spreads along the extrusion wheel groove to form a thin metal layer. Under the action of the extrusion wheel (rotation speed is 12 rpm) and the plug, the thin metal layer on the wheel groove wall continuously enters the mold and accumulates, and then is extruded from the die hole to form an alloy rod; the funnel preheating temperature is 780 ° C, and the die hole diameter is 9.5 mm.

[0033] (4) The alloy rod obtained in step (3) is subjected to multiple drawing passes (total deformation of 80%) to obtain a wire, which is then annealed at 175°C / 1h to obtain a high-conductivity super-heat-resistant aluminum alloy wire, whose conductivity at 20°C is 61.5% IACS; the tensile strength is 162 MPa, and at the same time, after heat exposure at 280°C / 1h, the tensile strength retention rate can reach 91%.

[0034] Example 2

[0035] The present invention relates to a high-conductivity super-heat-resistant aluminum alloy wire and a preparation method thereof, comprising the following steps:

[0036] (1) Material preparation: Weigh Al-Ce master alloy and high-purity aluminum ingots according to the mass percentage of Ce: 2.2% and the balance of Al.

[0037] (2) Melting: Al-Ce master alloy and high-purity aluminum ingots are placed in a furnace for melting and stirred until uniformly mixed. The melt temperature is maintained at 775°C during the stirring process. Finally, the melt temperature is maintained at 735°C for 60 minutes to complete the melting.

[0038] (3) Preparation of Al-Ce alloy rods by gas-assisted continuous casting and extrusion: the molten alloy melt flows out from a funnel located above the extrusion wheel groove (the funnel diameter is 2.4 mm), and an inert gas (nitrogen gas, gas pressure is 0.25 MPa) is sprayed above the extrusion wheel groove. Under the combined action of gravity and the inert gas jet, the alloy melt spreads along the extrusion wheel groove to form a thin metal layer. Under the action of the extrusion wheel (rotation speed is 10 rpm) and the plug, the thin metal layer on the wheel groove wall continuously enters the mold and accumulates, and then is extruded from the die hole to form an alloy rod; the funnel preheating temperature is 790 ° C, and the die hole diameter is 9.5 mm.

[0039] (4) The alloy rod obtained in step (3) is subjected to multiple drawing passes (total deformation of 75%) to obtain a wire, which is then annealed at 190°C / 1h to obtain a high-conductivity super-heat-resistant aluminum alloy wire, whose conductivity at 20°C is 61.3% IACS; the tensile strength is 165 MPa, and at the same time, after heat exposure at 280°C / 1h, the tensile strength retention rate can reach 92%.

[0040] Example 3

[0041] The present invention relates to a high-conductivity super-heat-resistant aluminum alloy wire and a preparation method thereof, comprising the following steps:

[0042] (1) Material preparation: Weigh Al-Ce master alloy and high-purity aluminum ingots according to the mass percentage of Ce: 2.5% and the balance of Al.

[0043] (2) Melting: Al-Ce master alloy and high-purity aluminum ingots are placed in a furnace for melting and stirred until uniformly mixed. The melt temperature is maintained at 780°C during the stirring process. Finally, the melt temperature is maintained at 740°C for 60 minutes to complete the melting.

[0044] (3) Preparation of Al-Ce alloy rods by gas-assisted continuous casting and extrusion: the molten alloy melt flows out from a funnel located above the extrusion wheel groove (the funnel diameter is 2.0 mm), and an inert gas (nitrogen gas, gas pressure is 0.20 MPa) is sprayed above the extrusion wheel groove. Under the combined action of gravity and the inert gas jet, the alloy melt spreads along the extrusion wheel groove to form a thin metal layer. Under the action of the extrusion wheel (rotation speed is 8 rpm) and the plug, the thin metal layer on the wheel groove wall continuously enters the mold and accumulates, and then is extruded from the die hole to form an alloy rod; the funnel preheating temperature is 800 ° C, and the die hole diameter is 9.5 mm.

[0045] (4) The alloy rod obtained in step (3) is subjected to multiple drawing passes (total deformation of 70%) to obtain a wire, which is then annealed at 200°C / 1h to obtain a high-conductivity super-heat-resistant aluminum alloy wire, whose conductivity at 20°C is 61.0% IACS; the tensile strength is 166 MPa, and at the same time, after heat exposure at 280°C / 1h, the tensile strength retention rate can reach 92%.

[0046] Comparative Example 1

[0047] The specific parameters of this embodiment are the same as those of embodiment 1, except that the Ce content is 5%.

[0048] The obtained aluminum alloy wire has an electrical conductivity of 55% IACS at 20° C., which is significantly lower than the current standard requirement that the electrical conductivity of super heat-resistant aluminum alloy wires should be no less than 60% IACS.

[0049] By comparison, it can be seen that too high Ce content will form more Al11 The Ce3 phase will greatly reduce the mean free path of electrons and significantly reduce conductivity.

[0050] Comparative Example 2

[0051] The specific parameters of this embodiment are the same as those of embodiment 1, except that step (3) is replaced by: continuous casting and rolling (crystallization wheel cross-sectional area 2420mm 2 , crystallization wheel speed 2.3 rpm, Y-type continuous rolling mill stand number 13, casting temperature 720 ° C, billet temperature 540 ° C, rolling temperature 520 ° C) to prepare alloy rods with a diameter of about 9.5 mm.

[0052] The tensile strength of the obtained aluminum alloy wire is 120 MPa, which is significantly lower than the current standard requirement that the tensile strength of super heat-resistant aluminum alloy wires should be no less than 159 MPa.

[0053] By comparison, it can be seen that the lower solidification rate in the continuous casting and rolling process is prone to form coarse Al 11 The Ce3 phase has a very weak strengthening effect and will significantly reduce the strength of the alloy.

[0054] Comparative Example 3

[0055] The specific parameters of this embodiment are the same as those of embodiment 1, except that the annealing process in step 4 is omitted.

[0056] The obtained aluminum alloy wire has an electrical conductivity of 53% IACS at 20° C., which is significantly lower than the current standard requirement that the electrical conductivity of super heat-resistant aluminum alloy wires should be no less than 60% IACS.

[0057] By comparison, it can be seen that the large number of dislocations formed during the extrusion and drawing process will cause severe electron scattering. If they are not eliminated by annealing, the conductive performance will be significantly reduced.

[0058] While various embodiments of the present invention have been described above, the foregoing description is intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or improvements to existing technologies, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A high-conductivity super-heat-resistant aluminum alloy wire, characterized by: Calculated by mass percentage, its chemical composition is: Ce 2.0-2.5%, and the balance is Al.

2. The method for preparing a high-conductivity superheat-resistant aluminum alloy wire according to claim 1, wherein: The specific steps include: (1) Material preparation: Al-Ce master alloy and high-purity aluminum ingot were weighed according to their chemical compositions; (2) Melting: Place Al-Ce master alloy and high-purity aluminum ingot into a furnace for melting and stirring until the mixture is uniform; (3) Preparation of Al-Ce alloy rods by gas-assisted continuous casting and extrusion; (4) cold drawing the alloy rod obtained in step (3) to obtain a wire; (5) Annealing the wire obtained in step (4) to obtain a high-conductivity super-heat-resistant aluminum alloy wire.

3. The method for preparing a high-conductivity superheat-resistant aluminum alloy wire according to claim 2, wherein: In step (3), the melt temperature is maintained at 770-780°C during the stirring process, and finally kept at 730-740°C for 60 minutes.

4. The method for preparing a high-conductivity superheat-resistant aluminum alloy wire according to claim 2, wherein: In step (3), the specific process of gas-assisted continuous casting and extrusion is as follows: the smelted metal melt flows into the extrusion wheel groove from the preheated funnel located above the extrusion wheel. Under the action of the inert gas, the melt spreads out closely against the wall of the extrusion wheel groove and begins to solidify. After encountering a blockage, the solidifying billet begins to accumulate and gradually transfers into the extrusion die cavity, and is finally extruded from the die hole to form an alloy rod.

5. The method for preparing a high-conductivity superheat-resistant aluminum alloy wire according to claim 4, characterized in that: The diameter of the funnel in step (3) is 2.0-2.8 mm, and the funnel needs to be heated to 780-800° C. before pouring the alloy melt.

6. The method for preparing a high-conductivity superheat-resistant aluminum alloy wire according to claim 4, wherein: The gas pressure of the inert gas in step (3) is 0.2-0.3 MPa.

7. The method for preparing a high-conductivity superheat-resistant aluminum alloy wire according to claim 4, characterized in that: The rotation speed of the extrusion wheel in step (3) is 8-12 rpm.

8. The method for preparing a high-conductivity superheat-resistant aluminum alloy wire according to claim 4, wherein: In step (3), the preheating temperature of the extrusion die cavity is 300-350° C., and the die hole diameter is 9.5 mm.

9. The method for preparing a high-conductivity superheat-resistant aluminum alloy wire according to claim 2, wherein: In step (4), the cold drawing is performed for 4-6 times, with a total deformation of 70-80%.

10. The method for preparing a high-conductivity superheat-resistant aluminum alloy wire according to claim 2, wherein: In step (5), the annealing temperature is 175-200° C. and the annealing time is 1 h.

Images