A method for preparing ultra-long copper-tin alloy fine wire

Abstract

A method for preparing an ultra-long copper-tin alloy fine wire comprises the following steps: 1) weighing 99.4-99.9% copper and 0.1-0.6% tin by weight, and smelting them into ingots; 2) continuously casting the ingots into copper-tin alloy rods; 3) cold forging the copper-tin alloy rods for multiple passes, and heat treating when the deformation of the copper-tin alloy rods reaches 65%-75%, to obtain copper-tin alloy wire rods; 4) drawing the copper-tin alloy wire rods for multiple passes into copper-tin alloy fine wires. The copper-tin alloy fine wires change the cast structure appearing during continuous casting by cold forging, so that the wire structure is uniform and fine, has high tensile strength and high conductivity, and the structure is deformed in a coordinated manner during the wire drawing process, and is not easy to break. When the wire diameter is 0.03mm, the tensile strength is greater than 1000MPa, the conductivity is greater than 82%IACS, and the length of a single filament reaches 300,000 meters, accounting for no less than 85% of the total, with high production efficiency and excellent continuous processing capability.

Description

Technical Field

[0001] The invention relates to the technical field of metal processing, and in particular to a method for preparing an ultra-long copper-tin alloy fine wire. Background Art

[0002] Copper-tin alloy is a high-strength, high-conductivity copper alloy material with excellent bending, torsion, fatigue resistance, heat resistance and other comprehensive properties. Therefore, copper-tin alloy fine wires are widely used in new energy vehicles, drones and intelligent robots, manned spaceflight, lunar exploration, satellite navigation and other fields. With the development of science and technology, the high-tech field has put forward higher requirements on the mechanical-electrical properties of copper-tin wires, requiring copper-tin alloy wires to improve mechanical properties while ensuring conductivity; at present, the casting structure that appears during the continuous casting of the alloy is not completely eliminated during the processing of copper-tin alloy wires, making the processed wire structure uneven, resulting in inconsistent mechanical properties and conductivity of the wire, affecting the stability of the wire performance, and seriously reducing the subsequent continuous production capacity of fine wires, greatly reducing the quality and production efficiency of the product.

[0003] Publication No. CN116411202A discloses a copper-tin alloy wire and a preparation method thereof. The method removes impurities and refines grains by adding elements such as lanthanum, boron, and zirconium. However, the method uses hot forging to process ingots, which has low production efficiency and is prone to oxidation during processing. Publication No. CN107904434B discloses an ultra-fine and ultra-long copper alloy wire and a production method thereof. The method uses directional solidification technology to process copper-tin alloy wires, so that the tensile strength of the copper-tin alloy wires is greater than 800 MPa, the conductivity is greater than 70% IACS, and the proportion of single filaments greater than 30,000 meters in total is not less than 80%. However, the method directly anneals the continuously cast copper-tin alloy rods and then draws them into shape, which does not completely eliminate the defects of the as-cast structure, so that the strength and processing performance of the copper-tin alloy wires are still to be improved. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing ultra-long copper-tin alloy micro-wires in view of the deficiencies in the prior art. The copper-tin alloy micro-wires have high tensile strength and high conductivity, solve the problem of cast structure occurring during continuous casting, make the wires less likely to break during drawing, have the ability of continuous production, and improve production efficiency.

[0005] The object of the present invention is achieved in that:

[0006] The method for preparing ultra-long copper-tin alloy fine wire comprises the following steps:

[0007] 1) Weigh 99.4-99.9% copper and 0.1-0.6% tin by weight and smelt them into ingots;

[0008] 2) continuously casting the ingot into a copper-tin alloy rod;

[0009] 3) The copper-tin alloy rod is subjected to multiple cold rotary forgings. When the deformation of the copper-tin alloy rod reaches 65%-75%, heat treatment is performed, a protective atmosphere is introduced, the rod is heated to 450-550°C, kept warm for 40-80 minutes, and cooled to room temperature to obtain a copper-tin alloy wire rod;

[0010] 4) The copper-tin alloy wire rod is drawn into copper-tin alloy fine wire in multiple passes.

[0011] Step 1) The smelting is carried out in a vacuum furnace with a vacuum degree of ≤5.0×10 -2 Pa, heating temperature is 1100℃-1300℃, holding time is 2-3h, cooling with the furnace.

[0012] Step 2) The continuous casting is carried out in a bottom-drawn continuous casting furnace with a vacuum degree of ≤5.0×10 -2 Pa, filled with argon, the heating temperature is 1150℃-1250℃, the holding time is 20-40min, the guide rod speed of the downward continuous casting is 100-200mm / min, the cooling water temperature of the downward continuous casting is 20-35℃, and the cooling water flow rate is 25-40L / min.

[0013] Step 2) The diameter of the copper-tin alloy rod is 8-12 mm.

[0014] Step 3) The deformation amount of each cold rotary forging is 15%-25%.

[0015] Step 3) The protective atmosphere is argon.

[0016] Step 3) The diameter of the copper-tin alloy wire rod is 4 mm-6 mm.

[0017] In the step 4), when the diameter of the copper-tin alloy wire rod is ≥2mm, the deformation amount of each drawing pass is 15%-25%, and the wire drawing speed is 10-30m / min; when the diameter of the copper-tin alloy wire rod is 0.5mm≤<2mm, the deformation amount of each drawing pass is 10%-15%, and the wire drawing speed is 50-200m / min; when the diameter of the copper-tin alloy wire rod is <0.5mm, the deformation amount of each drawing pass is 5%-10%, and the wire drawing speed is 200-400m / min.

[0018] The beneficial effects of the present invention include the following:

[0019] (1) The method of the present invention adopts the method of melting the master alloy ingot and combining it with vacuum vertical continuous casting to solve the problem of component segregation in the copper-tin alloy casting process and avoid the inclusion of impurities such as inclusions and gas in the alloy;

[0020] (2) The present invention adopts multiple cold rotary forging and heat treatment to eliminate the cast structure formed in the continuous casting process, so that the copper-tin alloy grains are broken to form a uniform and fine structure, which provides a certain fine grain strengthening effect for the wire material, improves the tensile strength and electrical conductivity of the wire material, and because the structure is fine and uniform, the structure is coordinated and deformed during the wire micro-wire drawing process, and the wire is not easy to break, the continuous processing capability is excellent, and the production efficiency is high.

[0021] The experiment of the applicant shows that: the ultra-long copper-tin alloy fine wire prepared by the method of the present invention has a conductivity of >82% IACS, a tensile strength of >1000 MPa, and is not easy to break during drawing. The single length of the copper-tin alloy fine wire drawn with a length of 0.03 mm reaches 300,000 meters, accounting for ≥85% of the total number. The length of the single drawn wire is much longer than the 30,000 meters mentioned in the background technology, which greatly improves the yield rate and has the ability of continuous production, which is conducive to subsequent packaging, twisting, etc., and is used for the industrial implementation and application of wires. The performance of the prepared copper-tin alloy fine wire can reach a tensile strength of 1020 MPa and a conductivity of 83.2% IACS. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0023] Further description is given below in conjunction with the accompanying drawings and specific implementation methods.

[0024] Embodiment 1:

[0025] See also Figure 1 , preparing ultra-long copper-tin alloy fine wires, comprising the following steps:

[0026] 1) Weigh 99.73wt.% copper plate and 0.27wt.% tin particles into a graphite crucible and draw the vacuum to ≤5.0×10 -2 Pa, start heating, raise the temperature to 1200℃, keep it at this temperature for 3h, cool it with the furnace, and melt it into an ingot;

[0027] 2) Add the ingot into the down-draw continuous casting furnace and evacuate the vacuum to ≤5.0×10 -2 Pa, filled with argon, began to heat to 1160 ° C, kept warm for 20 minutes, the speed of the lower continuous casting rod was 100 mm / min, the cooling water temperature of the lower continuous casting was 25 ° C, the cooling water flow rate was 30 L / min, and the copper-tin alloy rod with a diameter of 8 mm was continuously cast;

[0028] 3) The copper-tin alloy rod is subjected to multiple cold rotary forgings, with a deformation amount of 20% in each pass. When the deformation amount of the copper-tin alloy rod reaches 75%, argon gas is filled in, heated to 500°C, and heat treated for 40 minutes to obtain a copper-tin alloy wire rod with a diameter of 4 mm;

[0029] 4) The copper-tin alloy wire rod is subjected to multiple drawing passes. When the diameter of the copper-tin alloy wire rod is ≥2mm, the deformation amount of each pass is 20% and the drawing speed is 25m / min; when the diameter of the drawn copper-tin alloy wire rod is 0.5mm≤<2mm, the deformation amount of each pass is 15% and the drawing speed is 50m / min; when the diameter of the drawn copper-tin alloy wire rod is <0.5mm, the deformation amount of each pass is 8% and the drawing speed is 200m / min, and a fine wire with a diameter of 0.03mm is obtained.

[0030] The test results show that the tensile strength of the ultra-long copper-tin alloy fine wire prepared in Example 1 is 1008 MPa, the conductivity is 82.6% IACS, and the fine wires with a single length of 300,000 meters account for 87% of the total.

[0031] Embodiment 2:

[0032] See also Figure 1 , preparing ultra-long copper-tin alloy fine wires, comprising the following steps:

[0033] 1) Weigh 99.73wt.% copper plate and 0.27wt.% tin particles into a graphite crucible and draw the vacuum to ≤5.0×10 -2 Pa, start heating, raise the temperature to 1220℃, keep it warm for 3h, cool it with the furnace, and melt it into ingot;

[0034] 2) Add the ingot into the down-draw continuous casting furnace and evacuate to 5.0×≤10 -2 Pa, fill with argon, start heating to 1180℃, keep warm for 20min, the rod speed of the lower continuous casting is 100mm / min, the cooling water temperature of the lower continuous casting is 25℃, the cooling water flow rate is 30L / min, and the copper-tin alloy rod with a diameter of 12mm is continuously cast;

[0035] 3) The copper-tin alloy rod is subjected to multiple cold rotary forgings, with a deformation amount of 20% in each pass. When the deformation amount of the copper-tin alloy rod reaches 75%, argon gas is filled in, heated to 500°C, and heat treated for 60 minutes to obtain a copper-tin alloy wire rod with a diameter of 6 mm;

[0036] 4) The copper-tin alloy wire rod is subjected to multiple drawing passes. When the diameter of the copper-tin alloy wire rod is ≥2mm, the deformation amount of each pass is 20% and the drawing speed is 25m / min; when the diameter of the drawn copper-tin alloy wire rod is 0.5mm≤<2mm, the deformation amount of each pass is 15% and the drawing speed is 50m / min; when the diameter of the drawn copper-tin alloy wire rod is <0.5mm, the deformation amount of each pass is 8% and the drawing speed is 200m / min, and a fine wire with a diameter of 0.03mm is obtained.

[0037] The test results show that the tensile strength of the ultra-long copper-tin alloy fine wire prepared in Example 2 is 1026 MPa, the conductivity is 82.1% IACS, and the fine wires with a single length of 300,000 meters account for 86.5% of the total.

[0038] Embodiment 3:

[0039] See also Figure 1 , preparing ultra-long copper-tin alloy fine wires, comprising the following steps:

[0040] 1) Weigh 99.75wt.% copper plate and 0.25wt.% tin particles into a graphite crucible and evacuate the vacuum to ≤5.0×10 -2 Pa, start heating, raise the temperature to 1250℃, keep it for 3h, cool it with the furnace, and melt it into ingot;

[0041] 2) Add the ingot into the down-draw continuous casting furnace and evacuate the vacuum to ≤5.0×10 -2 Pa, fill with argon, start heating to 1200℃, keep warm for 20min, the rod speed of the lower continuous casting is 100mm / min, the cooling water temperature of the lower continuous casting is 25℃, the cooling water flow rate is 30L / min, and the copper-tin alloy rod with a diameter of 12mm is continuously cast;

[0042] 3) The copper-tin alloy rod is subjected to multiple cold rotary forgings, with a deformation amount of 20% in each pass. When the deformation amount of the copper-tin alloy rod reaches 75%, argon gas is filled in, heated to 500°C, and heat treated for 50 minutes to obtain a copper-tin alloy wire rod with a diameter of 6 mm;

[0043] 4) The copper-tin alloy wire rod is subjected to multiple drawing passes. When the diameter of the copper-tin alloy wire rod is ≥2mm, the deformation amount of each pass is 20% and the drawing speed is 25m / min; when the diameter of the drawn copper-tin alloy wire rod is 0.5mm≤<2mm, the deformation amount of each pass is 15% and the drawing speed is 50m / min; when the diameter of the drawn copper-tin alloy wire rod is <0.5mm, the deformation amount of each pass is 8% and the drawing speed is 200m / min, and a fine wire with a diameter of 0.03mm is obtained.

[0044] The test results show that the tensile strength of the ultra-long copper-tin alloy fine wire prepared in Example 3 is 1020 MPa, the conductivity is 83.2% IACS, and the fine wires with a wire diameter of 0.03 mm and a single length of 300,000 meters account for 87% of the total.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for preparing ultra-long copper-tin alloy fine wire, characterized in that: The following steps are involved: 1) Weigh 99.4-99.9% copper and 0.1-0.6% tin by weight and smelt them into ingots; 2) continuously casting the ingot into a copper-tin alloy rod, wherein the continuous casting is a bottom-draw continuous casting, and the diameter of the copper-tin alloy rod is 8-12 mm; 3) The copper-tin alloy rod is subjected to multiple cold rotary forgings. When the deformation of the copper-tin alloy rod reaches 65%-75%, heat treatment is performed, a protective atmosphere is introduced, the rod is heated to 450-550°C, kept warm for 40-80 minutes, and cooled to room temperature to obtain a copper-tin alloy wire rod; The diameter of the copper-tin alloy wire rod is 4mm-6mm; 4) The copper-tin alloy wire rod is drawn into copper-tin alloy fine wires in multiple passes.

2. The preparation method according to claim 1, characterized in that: Step 1) The smelting is carried out in a vacuum furnace with a vacuum degree of ≤5.0×10 -2 Pa, heating temperature is 1100℃-1300℃, holding time is 2-3h, cooling with the furnace.

3. The preparation method according to claim 1, characterized in that: Step 2) The continuous casting is carried out in a bottom-drawn continuous casting furnace with a vacuum degree of ≤5.0×10 -2 Pa, filled with argon, the heating temperature is 1150℃-1250℃, the holding time is 20-40min, the guide rod speed of the downward continuous casting is 100-200mm / min, the cooling water temperature of the downward continuous casting is 20-35℃, and the cooling water flow rate is 25-40L / min.

4. The preparation method according to claim 1, characterized in that: Step 3) The deformation amount of each cold rotary forging is 15%-25%.

5. The preparation method according to claim 1, characterized in that: Step 3) The protective atmosphere is argon.

6. The preparation method according to claim 1, characterized in that: In the step 4), when the diameter of the copper-tin alloy wire rod is ≥2mm, the deformation amount of each drawing pass is 15%-25%, and the wire drawing speed is 10-30m / min; when the diameter of the copper-tin alloy wire rod is 0.5mm≤<2mm, the deformation amount of each drawing pass is 10%-15%, and the wire drawing speed is 50-200m / min; when the diameter of the copper-tin alloy wire rod is <0.5mm, the deformation amount of each drawing pass is 5%-10%, and the wire drawing speed is 200-400m / min.

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