Copper alloy wire and method of making same

Abstract

The application discloses a copper alloy wire and a preparation method thereof, and the preparation method comprises the following steps: repeatedly performing heating and heat preservation treatment and rotary swaging on a rod of molybdenum metal or tungsten metal, so as to obtain a rotary swaged rod with a diameter of 6.5-8 mm; performing first annealing treatment on the rotary swaged rod, and then repeatedly performing cold drawing and second annealing treatment, so as to obtain a drawn wire with a diameter of 2-5 mm; and performing copper plating and copper infiltration treatment on the drawn wire, so as to obtain a tungsten-copper or molybdenum-copper alloy wire. The application can improve the compactness of the alloy wire, increase the thermal conductivity and electrical conductivity of the alloy wire, improve the utilization rate of raw materials, reduce the production cost, and make the obtained material meet the use requirements of different high-voltage switches and trigger electrodes.

Description

Technical Field

[0001] This invention relates to the technical field of processing methods for copper alloy wires, and particularly to the technical field of processing methods for tungsten copper or molybdenum copper wires. Background Technology

[0002] Tungsten-copper and molybdenum-copper alloys possess high strength, resistance to arc erosion, low coefficient of expansion, and high electrical and thermal conductivity, making them widely used in high-voltage electrical switches for contacts, electrodes, electronic packaging, and heat sinks. When these alloys are used in high-voltage switches and trigger electrodes, the requirements for specifications and performance are even more stringent. For example, the alloy diameter typically needs to be around 3 mm, forming a fine wire to ensure a tight fit with the switch structure and uniform current transmission. The alloy needs high thermal and electrical conductivity to ensure rapid current transfer and effective heat dissipation, preventing localized overheating and malfunctions. It also requires high density and low gas content to reduce defects, ensure high mechanical strength, minimize bubble formation, and improve arc resistance and thermal stability.

[0003] In existing technologies, there are two main methods for preparing tungsten copper and molybdenum copper alloy wires: one is the reduction method, which involves machining tungsten copper or molybdenum copper rods several times the target size to gradually reduce them to the required dimensions; the other is the rotary forging method, which involves multi-stage stretching and forging of tungsten copper or molybdenum copper rods on a rotary forging machine to gradually refine and lengthen them to the required dimensions. Of these two methods, the reduction method typically requires sintered tungsten copper or molybdenum copper rods, which inherently possess porosity defects that are difficult to eliminate and reduce material density, electrical and thermal conductivity, and mechanical strength. Reduction also results in significant waste of raw materials and increases manufacturing costs. Meanwhile, the rotary forging method is prone to fracture and splitting when processing hard and brittle tungsten copper or molybdenum copper alloys, making processing difficult and resulting in a low yield. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to propose a novel copper alloy wire and its preparation method. This preparation method can obtain tungsten-copper and molybdenum-copper alloy wires with adjustable composition ratios by controlling the internal gaps of tungsten and molybdenum wires and the thickness of the electroplated copper layer. This method can improve the density of the alloy wire, increase its thermal and electrical conductivity, improve the utilization rate of raw materials, and reduce production costs, so that the obtained material meets the application requirements of different high-voltage switches and trigger electrodes.

[0005] The technical solution of the present invention is as follows:

[0006] A method for preparing copper alloy wire, comprising:

[0007] The raw metal bar is heated and held at a certain temperature, and then forged at a forging rate of 1.2~1.6m / min. The heating and holding process and the forging process are repeated until a forged bar with a diameter of 6.5~8mm is obtained.

[0008] The forged bar is subjected to a first annealing treatment in a hydrogen atmosphere to obtain an annealed bar.

[0009] The annealed bar is cold-drawn at a drawing rate of 5~8m / min, and then subjected to a second annealing treatment in a hydrogen atmosphere. The above cold drawing and second annealing process is repeated until a drawn wire with a diameter of 2~5mm is obtained.

[0010] The drawn wire is cut, degreased and activated, and then copper-plated to obtain copper-plated wire.

[0011] In a hydrogen atmosphere, the copper-plated wire is subjected to copper infiltration treatment by melt infiltration method to obtain copper alloy wire with a diameter of 2~5mm;

[0012] The raw material metal is selected from tungsten and / or molybdenum; the temperature of the first annealing treatment is 800~900℃ and the time is 20~40min; the temperature of the second annealing treatment is 500~600℃ and the time is 10~30min, and the time gradually decreases as the diameter of the annealed bar decreases after drawing.

[0013] The above technical solutions of the present invention achieve the regulation of the internal gap of the raw material metal wires, namely tungsten wire and molybdenum wire, through heating and heat preservation treatment and control of process parameters such as rotary forging speed, drawing speed, annealing temperature and time. This makes the raw material metals tough and have excellent processing performance during rotary forging and drawing, without material fracture or splitting. When combined with the dissolution process and its parameters of the present invention, the resulting copper alloy wire has a dense and uniform structure, significantly improving the comprehensive performance of the copper alloy wire, the diameter control accuracy and the yield.

[0014] According to some preferred embodiments of the present invention, the temperature of the heating and heat preservation treatment is 800~1000℃ and the time is 10~30min.

[0015] According to some preferred embodiments of the present invention, during the cold drawing process, graphite emulsion is coated on the surface of the annealed bar as a lubricant.

[0016] According to some preferred embodiments of the present invention, the cutting is to cut the drawn filament into 300mm lengths.

[0017] According to some preferred embodiments of the present invention, the copper infiltration treatment is performed at a temperature of 1300~1400℃ for 2~3 hours.

[0018] According to some preferred embodiments of the present invention, obtaining the rod of the raw material metal includes:

[0019] The powder of the raw material metal is pressed into a rod-shaped blank by isostatic pressing;

[0020] The rod-shaped billet is sintered in a hydrogen atmosphere to obtain a rod of the raw material metal, wherein the sintering temperature is 1300~1500℃ and the sintering holding time is 1.5~3.5h.

[0021] According to some preferred embodiments of the present invention, the isostatic pressing pressure is 160~200MPa.

[0022] According to some preferred embodiments of the present invention, in the copper alloy wire, the mass content of the raw material metal is 50-90% of the total mass of the copper alloy wire.

[0023] According to some preferred embodiments of the present invention, the copper layer thickness obtained by the copper plating process is 0.09~0.4mm.

[0024] The present invention has the following beneficial effects:

[0025] The preparation method of the present invention can effectively improve the utilization rate of raw materials and reduce production costs. The tungsten copper or molybdenum copper alloy wire prepared by it has high density, the composition and ratio can be flexibly adjusted, the material diameter can be precisely controlled, and the thermal and mechanical properties of the material are excellent. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the preparation process of tungsten-copper or molybdenum-copper alloy wire in this invention. Detailed Implementation

[0027] The technical solutions of the present invention will be further described below with reference to the embodiments and accompanying drawings. The embodiments described below are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0028] Example 1

[0029] See attached document Figure 1 Tungsten-copper alloy wire is prepared through the following steps:

[0030] (1) 197 g of tungsten powder with a particle size of 5 µm was packed into a rubber sleeve with a diameter of 12.5 mm and pressed into a rod blank by isostatic pressing at 180 MPa;

[0031] (2) The billet is placed in a continuous sintering furnace under a hydrogen atmosphere, the temperature is controlled at 1400℃, and it is held for 2.5 h to obtain a tungsten rod with a diameter of 10 mm.

[0032] (3) Heat the tungsten rod to 900°C in a heating furnace and hold for 20 min. Then send it to a rotary forging machine to be forged to a diameter of 8 mm. The rotary forging speed is 1.2~1.6 m / min. Repeat the heating and rotary forging process to obtain a rod with a diameter of 6.5 mm.

[0033] (4) Anneal the obtained rod under a hydrogen atmosphere at a temperature of 800°C for 30 minutes. Then, cold draw the annealed rod. During the drawing process, graphite emulsion is coated on the surface of the rod as a lubricant. The drawing speed is 5-8 m / min. The rod passes through dies with diameters of 6 mm and 5.5 mm in sequence. Then, under a hydrogen atmosphere, the rod is annealed at 500°C for 10-20 minutes. The annealing time decreases as the diameter decreases. The above drawing and annealing processes are repeated until the tungsten rod is drawn into a wire of 2-5 mm. The wire is then cut into 300 mm lengths.

[0034] (5) The tungsten wire obtained in step (4) is degreased and activated, and then placed in an electroplating device. By adjusting the concentration of the electroplating solution and the electroplating time, a copper layer with a thickness of 0.16~0.40 mm is plated to obtain copper-plated tungsten wire. The activation process is as follows: 30-50 mL / L of nitric acid and 30-50 mL / L of sulfuric acid are mixed in water to prepare an activation solution. Then, the tungsten wire is completely immersed in the activation solution and stirred thoroughly with ultrasound. The activation process lasts for 2-5 seconds. After activation, the tungsten wire is removed and the surface of the tungsten wire is rinsed with clean water to remove the residual activation solution.

[0035] (6) Place the copper-plated tungsten wire in a melting furnace under a hydrogen atmosphere for copper infiltration. The copper infiltration temperature is 1300℃ and the holding time is 2h to obtain tungsten copper alloy wire with a diameter of 2~5 mm.

[0036] The tungsten-copper alloy wire prepared in this embodiment has a diameter of 2-5 mm, a length of 300 mm, a tungsten content of 80 wt%, and a copper content of 20 wt%.

[0037] Example 2

[0038] See attached document Figure 1 Tungsten-copper alloy wire is prepared through the following steps:

[0039] (1) 245 g of tungsten powder with a particle size of 5 µm was packed into a rubber sleeve with a diameter of 12.5 mm and pressed into a rod blank by isostatic pressing at 200 MPa;

[0040] (2) The billet is placed in a continuous sintering furnace under a hydrogen atmosphere, the temperature is controlled at 1400℃, and it is held for 2.5 h to obtain a tungsten rod with a diameter of 10 mm.

[0041] (3) Heat the tungsten rod to 900°C in a heating furnace and hold for 20 min. Then send it to a rotary forging machine to be forged to a diameter of 8 mm. The rotary forging speed is 1.2~1.6 m / min. Repeat the heating and rotary forging process to obtain a rod with a diameter of 6.5 mm.

[0042] (4) Anneal the obtained rod under a hydrogen atmosphere at a temperature of 800°C for 30 minutes. Then, cold draw the annealed rod. During the drawing process, graphite emulsion is coated on the surface of the rod as a lubricant. The drawing speed is 5-8 m / min. The rod passes through dies with diameters of 6 mm and 5.5 mm in sequence. Then, under a hydrogen atmosphere, the rod is annealed at 500°C for 10-20 minutes. The annealing time decreases as the diameter decreases. The above drawing and annealing processes are repeated until the tungsten rod is drawn into a wire of 2-5 mm. The wire is then cut into 300 mm lengths.

[0043] (5) The tungsten wire obtained in step (4) is degreased and activated, and then placed in an electroplating device. By adjusting the concentration of the electroplating solution and the electroplating time, a copper layer with a thickness of 0.09~0.23 mm is plated to obtain copper-plated tungsten wire. The activation process is as follows: 30-50 mL / L of nitric acid and 30-50 mL / L of sulfuric acid are mixed in water to prepare an activation solution. Then, the tungsten wire is completely immersed in the activation solution and stirred thoroughly using ultrasound. The activation process lasts for 2-5 seconds. After activation, the tungsten wire is removed and the surface of the tungsten wire is rinsed with clean water to remove the residual activation solution.

[0044] (6) Place the copper-plated tungsten wire in a melting furnace under a hydrogen atmosphere for copper infiltration. The copper infiltration temperature is 1300℃ and the holding time is 2h to obtain tungsten copper alloy wire with a diameter of 2~5 mm.

[0045] The tungsten-copper alloy wire prepared in this embodiment has a diameter of 2-5 mm, a length of 300 mm, a tungsten content of 90 wt%, and a copper content of 10 wt%.

[0046] Example 3

[0047] See attached document Figure 1 The molybdenum-copper alloy wire is prepared by the following steps:

[0048] (1) 155 g of molybdenum powder with a particle size of 5 µm was loaded into a rubber sleeve with a diameter of 15 mm and pressed into a rod blank by isostatic pressing at 160 MPa.

[0049] (2) The billet is placed in a continuous sintering furnace under a hydrogen atmosphere, the temperature is controlled at 1400℃, and it is held for 2.5 h to obtain a molybdenum rod with a diameter of 12 mm.

[0050] (3) Heat the molybdenum rod to 900°C in a heating furnace and hold for 20 min. Then send it to a rotary forging machine to be forged to a diameter of 10 mm. The rotary forging speed is 1.2~1.6 m / min. Repeat the heating and rotary forging process until a rod with a diameter of 8 mm is obtained.

[0051] (4) The obtained rod is annealed in a hydrogen atmosphere at a temperature of 900°C for 30 minutes. The annealed rod is then cold-drawn. Graphite emulsion is coated on the surface of the rod as a lubricant during the drawing process. The drawing speed is 5-8 m / min. The rod passes through dies with diameters of 7.5 mm and 7 mm in sequence. Then, it is annealed in a hydrogen atmosphere at 600°C for 10-20 minutes. The annealing time decreases as the diameter decreases. The above drawing and annealing processes are repeated until the molybdenum rod is drawn into a wire of 2-5 mm. The wire is then cut into 300 mm lengths.

[0052] (5) The molybdenum wire obtained in step (4) is degreased and activated, and then placed in an electroplating device. By adjusting the concentration of the electroplating solution and the electroplating time, a copper layer with a thickness of 0.15~0.38mm is plated to obtain copper-plated molybdenum wire. The activation process is as follows: 30-50 mL / L of nitric acid and 30-50 mL / L of sulfuric acid are mixed in water to prepare an activation solution. Then, the molybdenum wire is completely immersed in the activation solution and stirred thoroughly using ultrasound. The activation process lasts for 2-5 seconds. After activation, the molybdenum wire is removed and the surface of the molybdenum wire is rinsed with clean water to remove the residual activation solution.

[0053] (6) The copper-plated molybdenum wire is placed in a melting furnace under a hydrogen atmosphere for copper infiltration. The copper infiltration temperature is 1300℃ and the holding time is 2h to obtain a molybdenum-copper alloy wire with a diameter of 2~5 mm.

[0054] The molybdenum-copper alloy wire prepared in this embodiment has a diameter of 2-5 mm, a length of 300 mm, a molybdenum content of 70 wt%, and a copper content of 30 wt%.

[0055] Example 4

[0056] See attached document Figure 1 The molybdenum-copper alloy wire is prepared by the following steps:

[0057] (1) 180 g of molybdenum powder with a particle size of 5 µm was loaded into a rubber sleeve with a diameter of 15 mm and pressed into a rod blank by isostatic pressing at 180 MPa.

[0058] (2) The billet is placed in a continuous sintering furnace under a hydrogen atmosphere, the temperature is controlled at 1400℃, and it is held for 2.5 h to obtain a molybdenum rod with a diameter of 12 mm.

[0059] (3) Heat the molybdenum rod to 900°C in a heating furnace and hold for 20 min. Then send it to a rotary forging machine to be forged to a diameter of 10 mm. The rotary forging speed is 1.2~1.6 m / min. Repeat the heating and rotary forging process until a rod with a diameter of 8 mm is obtained.

[0060] (4) The obtained rod is annealed in a hydrogen atmosphere at a temperature of 900°C for 30 minutes. The annealed rod is then cold-drawn. Graphite emulsion is coated on the surface of the rod as a lubricant during the drawing process. The drawing speed is 5-8 m / min. The rod passes through dies with diameters of 7.5 mm and 7 mm in sequence. Then, it is annealed in a hydrogen atmosphere at 600°C for 10-20 minutes. The annealing time decreases as the diameter decreases. The above drawing and annealing processes are repeated until the molybdenum rod is drawn into a wire of 2-5 mm. The wire is then cut into 300 mm lengths.

[0061] (5) The molybdenum wire obtained in step (4) is degreased and activated, and then placed in an electroplating device. By adjusting the concentration of the electroplating solution and the electroplating time, a copper layer with a thickness of 0.11~0.26 mm is plated to obtain copper-plated molybdenum wire. The activation process is as follows: 30-50 mL / L of nitric acid and 30-50 mL / L of sulfuric acid are mixed in water to prepare an activation solution. Then, the molybdenum wire is completely immersed in the activation solution and stirred thoroughly using ultrasound. The activation process lasts for 2-5 seconds. After activation, the molybdenum wire is removed and the surface of the molybdenum wire is rinsed with clean water to remove the residual activation solution.

[0062] (6) The copper-plated molybdenum wire is placed in a melting furnace under a hydrogen atmosphere for copper infiltration. The copper infiltration temperature is 1300℃ and the holding time is 2h to obtain a molybdenum-copper alloy wire with a diameter of 2~5 mm.

[0063] The molybdenum-copper alloy wire prepared in this embodiment has a diameter of 2-5 mm, a length of 300 mm, a molybdenum content of 80 wt%, and a copper content of 20 wt%.

[0064] It should be noted that the above descriptions are merely preferred embodiments of the present invention and should not limit the scope of protection of the technical solutions of the present invention. Any modifications made to the technical solutions described in the foregoing embodiments, or equivalent substitutions of technical features, by those skilled in the art 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 copper alloy wire, characterized in that, It includes: The raw metal bar is heated and held at a certain temperature, and then forged at a forging rate of 1.2~1.6m / min. The heating and holding process and the forging process are repeated until a forged bar with a diameter of 6.5~8mm is obtained. The forged bar is subjected to a first annealing treatment in a hydrogen atmosphere to obtain an annealed bar. The annealed bar is cold-drawn at a drawing rate of 5~8m / min, and then subjected to a second annealing treatment in a hydrogen atmosphere. The above cold drawing and second annealing process is repeated until a drawn wire with a diameter of 2~5mm is obtained. The drawn wire is cut, degreased and activated, and then copper-plated to obtain copper-plated wire. In a hydrogen atmosphere, the copper-plated wire is subjected to copper infiltration treatment by melt infiltration method to obtain copper alloy wire with a diameter of 2~5mm; The raw material metal is selected from tungsten or molybdenum; the temperature of the first annealing treatment is 800-900℃ and the time is 20-40 min; the temperature of the second annealing treatment is 500-600℃ and the time is 10-30 min, and the time gradually decreases as the diameter of the annealed bar decreases after drawing.

2. The preparation method according to claim 1, characterized in that, The heating and heat preservation treatment is performed at a temperature of 800~1000℃ for a time of 10~30 minutes.

3. The preparation method according to claim 1, characterized in that, During the cold drawing process, graphite emulsion is coated on the surface of the annealed bar as a lubricant.

4. The preparation method according to claim 1, characterized in that, The cutting refers to cutting the drawn wire into 300mm lengths.

5. The preparation method according to claim 1, characterized in that, The copper infiltration treatment is performed at a temperature of 1300~1400℃ for 2~3 hours.

6. The preparation method according to claim 1, characterized in that, Obtaining the raw material metal rods includes: The raw material metal powder is pressed into a rod-shaped blank by isostatic pressing; The rod-shaped billet is sintered in a hydrogen atmosphere to obtain a rod of the raw material metal, wherein the sintering temperature is 1300~1500℃ and the sintering holding time is 1.5~3.5h.

7. The preparation method according to claim 6, characterized in that, The isostatic pressing pressure is 160~200MPa.

8. The preparation method according to claim 1, characterized in that, In the copper alloy wire, the mass content of the raw material metal is 50-90% of the total mass of the copper alloy wire.

9. The preparation method according to claim 1, characterized in that, The copper layer thickness obtained by the copper plating process is 0.09~0.4mm.

10. The copper alloy wire prepared by the preparation method according to any one of claims 1-9.

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