A high-strength copper alloy microwire and its preparation method

Abstract

This invention discloses a method for preparing high-strength copper alloy micro-wires, comprising the following steps: (1) Silver, tin, rare earth cerium or scandium, and the remaining cathode copper are added to a vacuum melting furnace, the furnace door is closed, and the cooling circulating water and vacuum pump are turned on in sequence; then the furnace heating power supply and the external electromagnetic field system are turned on simultaneously for heating and heat preservation; after the heat preservation is completed, the servo traction system switch is turned on to lead out the copper alloy rod, and the rod is continuously fed through the feeding port to cast the copper alloy rod; (2) The copper alloy rod is rolled with a high processing rate; (3) The rolled copper alloy wire blank is drawn into a copper alloy wire with a diameter of 0.01 to 0.03 mm. This invention also discloses a high-strength copper alloy micro-wire prepared by the above preparation method. This invention has the advantages of simple manufacturing method, no end breakage during drawing, high product yield, and high production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of new non-ferrous metal material preparation technology, specifically relating to a high-strength copper alloy microwire and its preparation method. Background Technology

[0002] Copper wire is an important material in the electronics and power industry, accounting for the largest proportion of copper consumption in my country. With the development trend of high-performance, miniaturized, and intelligent electronic devices, high-strength and highly conductive micro-electronic wires (with a diameter less than 0.05 mm) are widely used in consumer electronics, new energy vehicles, smart devices, and medical devices. Copper-silver and copper-tin alloys, due to their combination of high strength and high conductivity, are experiencing increasing demand year by year. The main production methods for copper wire include continuous casting and rolling / upward drawing + rolling / continuous extrusion + drawing technology. Continuous casting and rolling and upward drawing methods mainly suffer from defects such as difficulty in removing impurities from alloy smelting, high oxygen content (greater than 50 ppm), and poor casting quality. This results in high breakage rates and low yields during the micro-wire drawing process, making it impossible to continuously produce micro-copper wires with diameters of 0.05 mm or even less than 0.03 mm. Most of these copper alloy micro-wires rely on imports.

[0003] Chinese patent CN112195360B discloses a method for preparing ultra-high tensile rare earth copper-silver alloy ultrafine electronic wires. The alloy contains 1% to 4% silver by mass, 0.01% to 0.04% rare earth lanthanum by mass, and the mass ratio of silver to rare earth lanthanum is 1:0.01, with the remainder being copper. The process steps of this method include: (1) batching; (2) vacuum melting and downward continuous casting; (3) peeling; (4) continuous extrusion; (5) solution treatment; (6) peeling; (7) Y-rolling; (8) large drawing; (9) medium drawing; (10) small drawing; (11) micro drawing; and multiple micro drawing to obtain ultrafine electronic wires with a diameter of 0.01 to 0.03 mm. This patent uses a continuous extrusion, solution treatment and rolling process to prepare copper-silver alloy ultrafine wires with a tensile strength ≥1GPa and an elongation ≥1% of 0.01-0.03mm. The production process is long and inefficient, and requires two peeling processes, resulting in a low product yield.

[0004] Chinese patent CN106282651B discloses a copper-silver rare-earth alloy ultrafine wire and its production method. The copper-silver rare-earth alloy composition is: 1-25 wt% silver, 0.01-0.04 wt% yttrium, with the balance being copper and unavoidable impurities; or 1-25 wt% silver, 0.10-0.30 wt% lanthanum, with the balance being copper and unavoidable impurities; or 1-25 wt% silver, 0.01-0.02 wt% yttrium, 0.05-0.15 wt% lanthanum, with the balance being copper and unavoidable impurities. This patent first uses a vacuum induction furnace to prepare the copper-silver rare-earth alloy billet, then melts and casts it into a copper-silver rare-earth alloy rod with a diameter of Φ12.5-20 mm in a non-vacuum casting furnace under an inert atmosphere. Subsequent processes such as rolling, intermediate heat treatment, medium drawing, small drawing, and micro drawing can produce wire with a diameter of Φ0.025-0.05 mm. However, this method involves two melting and casting processes: alloy billet and alloy rod. The manufacturing process is relatively complicated, and the oxygen content of the cast alloy rod is relatively high (≥3ppm).

[0005] Chinese patent CN113967671A discloses a method for manufacturing high-strength, high-conductivity Cu-Ag alloy microwires. The method involves preparing Cu-Ag alloy cast rods using a bottom-drawing vacuum casting process, with a mass percentage of 1-5 wt% silver, 0-400 ppm rare-earth lanthanum, and the remainder copper. The alloy cast rods are then continuously extruded to obtain rod blanks with a diameter greater than or equal to 4 mm. These blanks are then subjected to multi-die cold drawing, annealed, and drawn again to finally produce Cu-Ag alloy microwires with a diameter of 0.016-0.055 mm. The resulting microwires have a tensile strength ≥700 MPa and a conductivity ≥75% IACS. This patent employs a continuous extrusion, multi-die cold drawing, and intermediate annealing process, resulting in a relatively long production process and lower tensile strength in the final product.

[0006] Chinese patent CN103276236A discloses a silver-copper strip material and its production process, with the following mass percentages: total copper and silver ≥99.95%, of which silver content is 0.04-0.15%; oxygen content ≤0.0005%; tin content 0.005-0.05%; rare earth content 0.01-0.05%; and total other impurities ≤0.01%. The process steps include: (1) melting and casting; (2) continuous extrusion; (3) cold rolling; (4) annealing; (5) cold rolling; (6) slitting; and (7) packaging and warehousing. The smelting process of this patent does not use vacuum or atmosphere protection, resulting in a high oxygen content. The oxygen content of the prepared strip material is ≤0.0005% (5ppm), which affects the overall performance of the product. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing high-strength copper alloy microwires.

[0008] To solve the above technical problems, the present invention adopts the following technical solution:

[0009] A method for preparing high-strength copper alloy microwires includes the following steps:

[0010] (1) Vacuum melting and continuous casting: 0.15% to 1.50% silver, 0.10% to 0.50% tin, 0.05% to 0.18% rare earth cerium or scandium, and the balance of cathode copper are put into the vacuum melting furnace. The furnace door is closed, and the cooling circulating water and vacuum pump are turned on in sequence. Then, the furnace heating power supply and the external electromagnetic field system are turned on at the same time for heating and heat preservation. After the heat preservation is completed, the servo traction system switch is turned on to lead out the copper alloy rod. The rod is continuously fed through the feeding port to cast a copper alloy rod with a diameter of 14 to 20 mm.

[0011] (2) Ultra-high processing rate cold rolling: The above copper alloy rod is rolled into copper alloy wire with a diameter of less than 3mm by a cold rolling mill. The number of cold rolling passes is 6 to 18, the cold rolling speed is 5 to 25m / min, and the processing deformation rate is 95% to 98%.

[0012] (3) Continuous drawing: The above copper alloy wire blank is drawn into a copper alloy wire with a diameter of 0.01 to 0.03 mm.

[0013] Preferably, in step (1), the purity of the silver, tin, rare earth cerium or scandium is 99.99%, and the purity of the cathode copper is 99.95%.

[0014] Preferably, in step (1), the cooling water volume is 1000-8500 L / h and the water temperature is 15-45℃.

[0015] Preferably, in step (1), the vacuum pump evacuates the vacuum to a vacuum level of 1 to 50 Pa.

[0016] Preferably, in step (1), the temperature inside the smelting furnace is controlled at 1095-1290℃ and held for 0.5-5 hours.

[0017] Preferably, in step (1), the applied electromagnetic field current intensity is 30 to 160 A.

[0018] Preferably, in step (1), the traction speed is 20 to 180 mm / min.

[0019] Preferably, in step (1), during the traction process, the cooling water temperature is controlled at 15-40°C and the vacuum degree of the smelting furnace is 1-50Pa.

[0020] Preferably, the continuous drawing method is as follows: first, a copper alloy wire blank with a diameter of less than 3 mm is drawn into a copper alloy wire with a diameter of 0.9 mm, with 8 to 14 intermediate drawing passes and a drawing speed of 120 to 280 m / min; then, the 0.9 mm copper alloy wire blank is drawn into a copper alloy wire with a diameter of 0.1 mm, with 18 to 24 minor drawing passes and a drawing speed of 180 to 320 m / min; finally, the 0.1 mm copper alloy wire blank is drawn into a copper alloy wire with a diameter of 0.01 to 0.03 mm, with 18 to 26 minor drawing passes and a drawing speed of 220 to 380 m / min.

[0021] The present invention also provides a method for preparing high-strength copper alloy microwires as described above.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) In this invention, silver (Ag), tin (Sn) and rare earth cerium (Ce) or scandium (Sc) are added to the copper matrix. Silver (Ag) has little effect on the conductivity of copper alloy and plays a role in solid solution strengthening, which can significantly improve the tensile strength of copper alloy. Tin (Sn) atoms can dissolve into the copper matrix to form a solid solution, causing lattice distortion and generating a stress field that hinders the movement of dislocations, thereby improving the strength of the alloy and playing a synergistic role in solid solution strengthening. It can also improve the work hardening rate and softening temperature. The addition of chemically active rare earth cerium (Ce) or scandium (Sc) can preferentially react with impurity elements and has the ability to absorb a large amount of gas, thereby purifying the copper melt, reducing the impurity content and oxidation. The atomic radius of rare earth elements is 36%-60% larger than that of copper. Therefore, rare earth atoms can easily fill the surface defects of new phases in copper alloy grains, hinder the continued growth of grains, thereby refining the grain structure and improving the strength and toughness of the alloy.

[0024] (2) The present invention adopts a continuous vacuum melting and casting method to remove impurity elements, reduce oxygen content, and improve the purity of melt under continuous vacuum conditions. The continuous feeding and casting produces copper alloy rods with excellent ingot quality, low oxygen content and other impurity content, which is beneficial for drawing into copper alloy micro wires with a diameter of 0.03 mm and below.

[0025] (3) This invention prepares high-strength copper alloy micro wires with diameters of 0.01 to 0.03 mm by ultra-high processing rate cold rolling (processing deformation rate of 95% to 98%) and continuous drawing. Since the solid solubility of Ag and Sn in the copper matrix at room temperature is limited, a certain proportion of Ag-rich and Sn-rich reinforcing phases will appear in the Cu-Ag-Sn ternary alloy structure. Adding trace amounts of rare earth elements can make the distribution of Ag-rich and Sn-rich reinforcing phases more dispersed. After ultra-high processing rate cold rolling deformation, a fibrous morphology can be formed. In this case, in addition to the work hardening effect, there is also the effect of fibrous phase reinforcement, which can greatly increase the strength. Moreover, no intermediate annealing is required. It has the advantages of simple manufacturing method, no breakage phenomenon during drawing, high product yield, and high production efficiency. Detailed Implementation

[0026] To facilitate a better understanding of the present invention, the following examples are provided. These examples fall within the scope of protection of the present invention, but do not limit the scope of protection of the present invention.

[0027] Example 1

[0028] A method for preparing high-strength copper alloy microwires includes the following steps:

[0029] (1) Vacuum melting and continuous casting: 0.15% silver (99.99% purity), 0.15% tin (99.99% purity), 0.05% rare earth cerium (99.99% purity), and the balance of cathode copper (99.95% purity) are added to the vacuum melting furnace. The furnace door is closed, the cooling water circulation is turned on with a flow rate of 1000L / h and a water temperature of 15℃, and the vacuum pump is turned on to evacuate the furnace. The vacuum degree is maintained at 1Pa. Then, the furnace heating power supply and the external electromagnetic field system are turned on simultaneously. The external electromagnetic field current intensity is 30A, and the furnace temperature is controlled at 1095℃ for 5 hours. After the holding period, the servo traction system is turned on to pull out the copper alloy rod at a traction speed of 20mm / min. During the traction process, the cooling water temperature is controlled at 15℃ and the furnace vacuum degree is maintained at 1Pa. The material is continuously added through the feeding port to cast copper alloy rods with a diameter of 14-20mm.

[0030] (2) Ultra-high processing rate cold rolling: The above copper alloy rod is rolled into copper alloy wire with a diameter of less than 3mm by a cold rolling mill. The cold rolling passes are 6, the cold rolling speed is 5m / min, and the processing deformation rate is 95%.

[0031] (3) Continuous drawing: First, draw the copper alloy wire blank with a diameter of less than 3 mm into a copper alloy wire with a diameter of 0.9 mm. The number of intermediate drawing passes is 8, and the intermediate drawing speed is 120 m / min. Then, draw the 0.9 mm copper alloy wire blank into a copper alloy wire with a diameter of 0.1 mm. The number of minor drawing passes is 18, and the minor drawing speed is 180 m / min. Finally, draw the 0.1 mm copper alloy wire blank into a copper alloy wire with a diameter of 0.01 to 0.03 mm. The number of minor drawing passes is 18, and the minor drawing speed is 220 m / min.

[0032] Example 2

[0033] A method for preparing high-strength copper alloy microwires includes the following steps:

[0034] (1) Vacuum melting and continuous casting: 1.5% silver (99.99% purity), 0.10% tin (99.99% purity), 0.10% rare earth cerium (99.99% purity), and the balance of cathode copper (99.95% purity) are added to the vacuum melting furnace. The furnace door is closed, the cooling water circulation is turned on, the cooling water flow rate is 5000L / h, the water temperature is 30℃, and the vacuum pump is turned on to draw a vacuum, maintaining the vacuum degree at 25Pa. Then, the furnace heating power supply and the external electromagnetic field system are turned on simultaneously, the external electromagnetic field current intensity is 100A, and the furnace temperature is controlled at 1195℃ for 2 hours. After the holding period, the servo traction system is turned on to draw out the copper alloy rod at a traction speed of 100mm / min. During the traction process, the cooling water temperature is controlled at 25℃ and the furnace vacuum degree is 50Pa. The material is continuously fed through the feeding port to cast copper alloy rods with a diameter of 14-20mm.

[0035] (2) Ultra-high processing rate cold rolling: The above copper alloy rod is rolled into copper alloy wire with a diameter of less than 3mm by a cold rolling mill. The cold rolling passes are 12, the cold rolling speed is 20m / min, and the processing deformation rate is 97%.

[0036] (3) Continuous drawing: First, draw the copper alloy wire blank with a diameter of less than 3 mm into a copper alloy wire with a diameter of 0.9 mm. The number of intermediate drawing passes is 12, and the intermediate drawing speed is 200 m / min. Then, draw the 0.9 mm copper alloy wire blank into a copper alloy wire with a diameter of 0.1 mm. The number of minor drawing passes is 20, and the minor drawing speed is 250 m / min. Finally, draw the 0.1 mm copper alloy wire blank into a copper alloy wire with a diameter of 0.01 to 0.03 mm. The number of minor drawing passes is 20, and the minor drawing speed is 290 m / min.

[0037] Example 3

[0038] A method for preparing high-strength copper alloy microwires includes the following steps:

[0039] (1) Vacuum melting and continuous casting: 0.5% silver (99.99% purity), 0.50% tin (99.99% purity), 0.18% rare earth scandium (99.99% purity), and the balance of cathode copper (99.95% purity) are added to the vacuum melting furnace. The furnace door is closed, the cooling water circulation is turned on, the cooling water flow rate is 8500L / h, the water temperature is 45℃, and the vacuum pump is turned on to draw a vacuum, maintaining the vacuum degree at 50Pa. Then, the furnace heating power supply and the external electromagnetic field system are turned on simultaneously, the external electromagnetic field current intensity is 160A, the furnace temperature is controlled at 1290℃, and the temperature is held for 0.5h. After the holding period, the servo traction system is turned on to draw out the copper alloy rod at a traction speed of 180mm / min. During the traction process, the cooling water temperature is controlled at 40℃ and the furnace vacuum degree is 50Pa. The material is continuously fed through the feeding port to cast copper alloy rods with a diameter of 14-20mm.

[0040] (2) Ultra-high processing rate cold rolling: The above copper alloy rod is rolled into copper alloy wire with a diameter of less than 3mm by a cold rolling mill. The cold rolling passes are 18, the cold rolling speed is 25m / min, and the processing deformation rate is 98%.

[0041] (3) Continuous drawing: First, the copper alloy wire blank with a diameter of less than 3 mm is drawn into a copper alloy wire with a diameter of 0.9 mm. The number of intermediate drawing passes is 14 and the intermediate drawing speed is 280 m / min. Then, the 0.9 mm copper alloy wire blank is drawn into a copper alloy wire with a diameter of 0.1 mm. The number of minor drawing passes is 24 and the minor drawing speed is 320 m / min. Finally, the 0.1 mm copper alloy wire blank is drawn into a copper alloy wire with a diameter of 0.01 to 0.03 mm. The number of minor drawing passes is 26 and the minor drawing speed is 380 m / min.

[0042] Comparative Example 1

[0043] A method for preparing copper alloy microwires includes the following steps:

[0044] (1) Vacuum melting and continuous casting: 1.5% silver with a purity of 99.99% and the balance of cathode copper with a purity of 99.95% are put into the vacuum melting furnace. The furnace door is closed, the cooling water circulation is turned on, the cooling water flow rate is 5000L / h, the water temperature is 30℃, the vacuum pump is turned on to draw a vacuum, and the vacuum degree is maintained at 25Pa. Then, the furnace heating power supply and the external electromagnetic field system are turned on at the same time. The external electromagnetic field current intensity is 100A, and the temperature inside the melting furnace is controlled at 1195℃ and held for 2 hours. After the holding period, the servo traction system is turned on to lead out the copper alloy rod at a traction speed of 100mm / min. During the traction process, the cooling water temperature is controlled at 25℃ and the vacuum degree of the melting furnace is 50Pa. The material is continuously fed through the feeding port to cast copper alloy rods with a diameter of 14-20mm.

[0045] (2) Cold rolling: The above copper alloy rod is rolled into copper alloy wire with a diameter of less than 3mm by a cold rolling mill. The cold rolling passes are 12, the cold rolling speed is 20m / min, and the processing deformation rate is 90%.

[0046] (3) Continuous drawing: First, draw the copper alloy wire blank with a diameter of less than 3 mm into a copper alloy wire with a diameter of 0.9 mm. The number of intermediate drawing passes is 12, and the intermediate drawing speed is 200 m / min. Then, draw the 0.9 mm copper alloy wire blank into a copper alloy wire with a diameter of 0.1 mm. The number of minor drawing passes is 20, and the minor drawing speed is 250 m / min. Finally, draw the 0.1 mm copper alloy wire blank into a copper alloy wire with a diameter of 0.01 to 0.03 mm. The number of minor drawing passes is 20, and the minor drawing speed is 290 m / min.

[0047] Comparative Example 2

[0048] A method for preparing copper alloy microwires includes the following steps:

[0049] (1) Vacuum melting and continuous casting: 1.5% silver (99.99% purity), 0.10% tin (99.99% purity), and the balance of cathode copper (99.95% purity) are added to the vacuum melting furnace. The furnace door is closed, the cooling water circulation is turned on, the cooling water flow rate is 5000L / h, the water temperature is 30℃, and the vacuum pump is turned on to evacuate the furnace. The vacuum degree is maintained at 25Pa. Then, the furnace heating power supply and the external electromagnetic field system are turned on at the same time. The external electromagnetic field current intensity is 100A, and the furnace temperature is controlled at 1195℃ for 2 hours. After the holding period, the servo traction system is turned on to pull out the copper alloy rod at a traction speed of 100mm / min. During the traction process, the cooling water temperature is controlled at 25℃ and the furnace vacuum degree is 50Pa. The material is continuously fed through the feeding port to cast copper alloy rods with a diameter of 14-20mm.

[0050] (2) Cold rolling: The above copper alloy rod is rolled into copper alloy wire with a diameter of less than 3mm by a cold rolling mill. The cold rolling passes are 12, the cold rolling speed is 20m / min, and the processing deformation rate is 90%.

[0051] (3) Continuous drawing: First, draw the copper alloy wire blank with a diameter of less than 3 mm into a copper alloy wire with a diameter of 0.9 mm. The number of intermediate drawing passes is 12, and the intermediate drawing speed is 200 m / min. Then, draw the 0.9 mm copper alloy wire blank into a copper alloy wire with a diameter of 0.1 mm. The number of minor drawing passes is 20, and the minor drawing speed is 250 m / min. Finally, draw the 0.1 mm copper alloy wire blank into a copper alloy wire with a diameter of 0.01 to 0.03 mm. The number of minor drawing passes is 20, and the minor drawing speed is 290 m / min.

[0052] Comparative Example 3

[0053] A method for preparing copper alloy microwires includes the following steps:

[0054] (1) Vacuum melting and continuous casting: 1.5% silver (99.99% purity), 0.10% rare earth cerium (99.99% purity), and the balance of cathode copper (99.95% purity) are added to the vacuum melting furnace. The furnace door is closed, the cooling water circulation is turned on, the cooling water flow rate is 5000L / h, the water temperature is 30℃, and the vacuum pump is turned on to draw a vacuum, maintaining the vacuum degree at 25Pa. Then, the furnace heating power supply and the external electromagnetic field system are turned on simultaneously, the external electromagnetic field current intensity is 100A, and the furnace temperature is controlled at 1195℃ for 2 hours. After the holding period, the servo traction system is turned on to draw out the copper alloy rod at a traction speed of 100mm / min. During the traction process, the cooling water temperature is controlled at 25℃ and the furnace vacuum degree is 50Pa. The material is continuously fed through the feeding port to cast copper alloy rods with a diameter of 14-20mm.

[0055] (2) Cold rolling: The above copper alloy rod is rolled into copper alloy wire with a diameter of less than 3mm by a cold rolling mill. The cold rolling passes are 12, the cold rolling speed is 20m / min, and the processing deformation rate is 90%.

[0056] (3) Continuous drawing: First, draw the copper alloy wire blank with a diameter of less than 3 mm into a copper alloy wire with a diameter of 0.9 mm. The number of intermediate drawing passes is 12, and the intermediate drawing speed is 200 m / min. Then, draw the 0.9 mm copper alloy wire blank into a copper alloy wire with a diameter of 0.1 mm. The number of minor drawing passes is 20, and the minor drawing speed is 250 m / min. Finally, draw the 0.1 mm copper alloy wire blank into a copper alloy wire with a diameter of 0.01 to 0.03 mm. The number of minor drawing passes is 20, and the minor drawing speed is 290 m / min.

[0057] Comparative Example 4

[0058] A method for preparing copper alloy microwires includes the following steps:

[0059] (1) Vacuum melting and continuous casting: 1.5% silver with a purity of 99.99% and the balance of cathode copper with a purity of 99.95% are put into the vacuum melting furnace. The furnace door is closed, the cooling water circulation is turned on, the cooling water flow rate is 5000L / h, the water temperature is 30℃, the vacuum pump is turned on to draw a vacuum, and the vacuum degree is maintained at 25Pa. Then, the furnace heating power supply and the external electromagnetic field system are turned on at the same time. The external electromagnetic field current intensity is 100A, and the temperature inside the melting furnace is controlled at 1195℃ and held for 2 hours. After the holding period, the servo traction system is turned on to lead out the copper alloy rod at a traction speed of 100mm / min. During the traction process, the cooling water temperature is controlled at 25℃ and the vacuum degree of the melting furnace is 50Pa. The material is continuously fed through the feeding port to cast copper alloy rods with a diameter of 14-20mm.

[0060] (2) Ultra-high processing rate cold rolling: The above copper alloy rod is rolled into copper alloy wire with a diameter of less than 3mm by a cold rolling mill. The cold rolling passes are 12, the cold rolling speed is 20m / min, and the processing deformation rate is 97%.

[0061] (3) Continuous drawing: First, draw the copper alloy wire blank with a diameter of less than 3 mm into a copper alloy wire with a diameter of 0.9 mm. The number of intermediate drawing passes is 12, and the intermediate drawing speed is 200 m / min. Then, draw the 0.9 mm copper alloy wire blank into a copper alloy wire with a diameter of 0.1 mm. The number of minor drawing passes is 20, and the minor drawing speed is 250 m / min. Finally, draw the 0.1 mm copper alloy wire blank into a copper alloy wire with a diameter of 0.01 to 0.03 mm. The number of minor drawing passes is 20, and the minor drawing speed is 290 m / min.

[0062] Performance testing experiment

[0063] The determination method is as follows:

[0064] (1) The tensile strength shall be determined according to the method specified in GB / T 4909.3;

[0065] (2) The elongation was determined according to the method specified in GB / T 4909.3;

[0066] (3) The conductivity shall be determined according to the method specified in GB / T 3048.2;

[0067] (4) The oxygen content shall be determined according to the method specified in YS / T 922;

[0068] (5) The softening temperature shall be determined according to the method specified in GB / T 33370.

[0069] The measurement results are shown in the table below:

[0070]

[0071]

[0072] As shown in the table above, the copper alloy microwires produced in Examples 1-3 of this invention have a tensile strength ≥997MPa, conductivity ≥82.1%IACS, elongation ≥1.0%, oxygen content <0.6ppm, and softening temperature >325℃. All these indicators are superior to those of Comparative Examples 1-4. It is evident that the technology of this invention has made significant progress, and the copper alloy microwires produced have advantages such as high strength, high conductivity, low oxygen content, and high stability.

[0073] Compared to Example 2, Comparative Example 1, containing only copper and silver (two conventional components) and without undergoing ultra-high processing rate cold rolling, exhibited significantly reduced tensile strength and softening temperature, while its oxygen content increased substantially. However, its conductivity and elongation showed little change. Comparative Examples 2-4, by adding tin and rare earth cerium to Comparative Example 1 and undergoing ultra-high processing rate cold rolling, respectively, showed some improvement in tensile strength and softening temperature, and a corresponding decrease in oxygen content. However, compared to Example 2, these results were still far inferior. This demonstrates that tin and rare earth cerium can synergistically improve the performance of copper alloy microwires through ultra-high processing rate cold rolling.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing high-strength copper alloy microwires, characterized in that, Includes the following steps: (1) Vacuum melting and continuous casting: 0.15% to 1.5% silver, 0.10% to 0.50% tin, 0.05% to 0.18% rare earth cerium or scandium, and the balance of cathode copper are put into a vacuum melting furnace. The furnace door is closed, and the cooling circulating water and vacuum pump are turned on in sequence. The vacuum pump is used to evacuate to a vacuum degree of 1 to 50 Pa. Then, the furnace heating power supply and the external electromagnetic field system are turned on at the same time to heat and hold the temperature. The temperature inside the melting furnace is controlled at 1095 to 1290℃ and held for 0.5 to 5 hours. The external electromagnetic field current intensity is 30 to 160 A. After the holding period, the servo traction system switch is turned on to lead out the copper alloy rod. The rod is continuously fed through the feeding port to cast a copper alloy rod with a diameter of 14 to 20 mm. (2) Ultra-high processing rate cold rolling: The above copper alloy rod is rolled into copper alloy wire with a diameter of less than 3mm by a cold rolling mill. The number of cold rolling passes is 6 to 18, the cold rolling speed is 5 to 25m / min, and the processing deformation rate is 95% to 98%. (3) Continuous drawing: The above copper alloy wire blank is drawn into a copper alloy wire with a diameter of 0.01 to 0.03 mm.

2. The method for preparing high-strength copper alloy microwires according to claim 1, characterized in that: In step (1), the purity of the silver, tin, rare earth cerium or scandium is 99.99%, and the purity of the cathode copper is 99.95%.

3. The method for preparing high-strength copper alloy microwires according to claim 1, characterized in that: In step (1), the cooling water volume is 1000-8500 L / h and the water temperature is 15-45℃.

4. The method for preparing high-strength copper alloy microwires according to claim 1, characterized in that: In step (1), the traction speed is 20-180 mm / min.

5. The method for preparing high-strength copper alloy microwires according to claim 1, characterized in that: In step (1), during the traction process, the cooling water temperature is controlled at 15-40℃ and the vacuum degree of the smelting furnace is controlled at 1-50Pa.

6. The method for preparing high-strength copper alloy microwires according to claim 1, characterized in that: The continuous drawing method is as follows: First, the copper alloy wire blank with a diameter of less than 3 mm is drawn into a copper alloy wire with a diameter of 0.9 mm, with 8 to 14 intermediate drawing passes and a drawing speed of 120 to 280 m / min; then, the 0.9 mm copper alloy wire blank is drawn into a copper alloy wire with a diameter of 0.1 mm, with 18 to 24 minor drawing passes and a drawing speed of 180 to 320 m / min; finally, the 0.1 mm copper alloy wire blank is drawn into a copper alloy wire with a diameter of 0.01 to 0.03 mm, with 18 to 26 minor drawing passes and a drawing speed of 220 to 380 m / min.

7. A high-strength copper alloy microwire prepared by a method according to any one of claims 1 to 6.

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