A method for preparing beryllium copper microwire with low stress relaxation performance

Abstract

The invention relates to the technical field of material processing, and discloses a method for preparing beryllium copper microwires with low stress relaxation performance, the method comprising: (1) vacuum casting: nickel, silicon and beryllium, and the rest is copper, are placed in a vacuum melting furnace for melting; (2) hot rotary forging: the wire blank in (1) is heated to 750°C by a tubular furnace, and a four-die rotary forging machine is used for rotary forging; (3) stretching: the wire blank in (2) is subjected to solid solution heat treatment; (4) multi-die stretching: the wire blank in (3) is subjected to multi-die high-precision stretching in a stretching die; (5) continuous annealing: the wire blank in (4) is subjected to solid solution treatment, and then continuous annealing. In the invention, by adding nickel and silicon, a small amount of nickel can sharply reduce the solubility of beryllium in copper, thereby improving the hardness of the material and improving the stress relaxation resistance.

Description

Technical Field

[0001] The invention relates to the technical field of material processing, in particular to a method for preparing beryllium copper microwires with low stress relaxation performance. Background Art

[0002] Beryllium copper microwire is a copper-based alloy material with beryllium as the basic alloying element. It is an aging-precipitation-strengthened copper-based alloy. After solid solution aging treatment, beryllium copper alloy has high elastic limit, small elastic hysteresis, and excellent properties such as corrosion resistance and wear resistance. It is widely used in weapons, aviation, aerospace and other fields. However, during the use of beryllium copper microwire, it was found that the stress relaxation resistance was low, especially under high temperature conditions (usually at 150°C), the stress relaxation rate was greatly improved, affecting the safety of material use. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a method for preparing beryllium copper microwires with low stress relaxation performance.

[0004] To achieve the above object, the present invention provides the following technical solution: a method for preparing beryllium copper microwires with low stress relaxation performance, the method comprising:

[0005] 1) Vacuum casting: 0.2% to 2% nickel, 0.05% to 0.5% silicon, 1.8% to 2% beryllium and impurities not exceeding 0.06% in total, and the rest is copper;

[0006] The wire is placed in a vacuum melting furnace for melting at a temperature of 1100°C to 1300°C, stirred during the melting process, and then semi-continuously cast to prepare a beryllium copper nickel silicon wire billet with a diameter of 5 to 10 mm and a length of 0.5 to 1.2 m;

[0007] 2) Hot rotary forging: heat the wire blank in 1) to 750℃~850℃, use a rotary forging machine to perform rotary forging, then water quench, and repeatedly perform hot rotary forging to obtain a wire blank of Φ1~2mm;

[0008] 3) Stretching: The wire blank in 2) is subjected to solution heat treatment at a temperature of 750-850°C for 2-4 minutes, and after water quenching, it is repeatedly drawn to obtain a wire blank of Φ0.3-0.6 mm;

[0009] 4) Multi-mode stretching: The wire blank in 3) is subjected to multi-mode stretching in a stretching die at a stretching speed of 5-20 m / s to obtain a wire blank of Φ0.03-0.075 mm;

[0010] 5) Continuous annealing: The wire billet of Φ0.03~0.075mm is solution treated at a temperature of 800℃~900℃, and then continuously annealed to finally obtain soft beryllium copper microwire of Φ0.03~0.075mm.

[0011] Preferably, the mass percentages of 1) are 1.7% nickel, 0.41% silicon, 1.9% beryllium and impurities not exceeding 0.06% in total, and the remainder is copper.

[0012] Preferably, the rotary forging machine in 2) rotates at a speed of 150-300 r / min, followed by water quenching, and 3-5 repeated hot rotary forgings to obtain a wire blank of Φ1-2 mm.

[0013] Preferably, in the above 3), a solution heat treatment is performed for 2-4 minutes, and after water quenching, 3-6 passes of repeated drawing are performed to obtain a wire blank with a diameter of 0.3-0.6 mm.

[0014] Preferably, in the step 5), a solution treatment is performed for 2-4 minutes, and then continuous annealing is performed at a temperature of 800° C., and finally soft beryllium copper microwires of Φ0.03-0.075 mm are obtained.

[0015] Compared with the prior art, the present invention provides a method for preparing beryllium copper microwires with low stress relaxation performance, which has the following beneficial effects:

[0016] 1. The present invention adds nickel and silicon. A small amount of nickel can sharply reduce the solubility of beryllium in copper, and can also form a NiBe precipitate phase with beryllium to inhibit grain growth and discontinuous grain boundary reaction. The grain size of beryllium copper microwires with Ni and Si added is approximately in the range of 600-800nm, and the grain size is refined, thereby improving the hardness of the material and the stress relaxation resistance.

[0017] 2. The addition of nickel and silicon in the present invention can cause Ni and Si atoms to precipitate from the copper matrix to form nano-scale δ-Ni2Si intermetallic compounds after solution quenching + aging treatment. The nano-scale precipitated particles interact with dislocations and hinder the movement of dislocations, thereby improving the strength of the material. Since the solute elements precipitate from the Cu matrix, the scattering effect of the copper matrix on electrons is weakened, thereby improving the electrical conductivity. Therefore, the addition of Ni and Si can enable the alloy to obtain higher strength while maintaining excellent electrical and thermal conductivity.

[0018] 3. The process flow of the present invention is short, which can save production costs. The process flow is optimized, and the continuous casting of materials into wire billets is changed to direct melting and casting of small-sized beryllium copper nickel silicon wire billets. This can shorten the process flow and thus prepare small-sized wire billets. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the process flow of the present invention;

[0020] Figure 2This is the grain size diagram of the beryllium copper microwire of the present invention with Ni and Si added (average grain size: 0.71834 μm). DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Embodiment 1:

[0022] (1) Vacuum casting:

[0023] 1.7% nickel, 0.41% silicon, 1.9% beryllium and impurities not exceeding 0.06% by mass, with the remainder being copper, are placed in a vacuum melting furnace for melting at a temperature of 1100°C. Mechanical stirring is performed during the melting process. Then, semi-continuous casting is performed to prepare a small-sized beryllium copper nickel silicon wire billet of Φ5mm and length of 0.5m.

[0024] (2) Hot rotary forging:

[0025] The wire blank in (1) was heated to 750°C in a tubular furnace, and was rotary forged using a four-die rotary forging machine at a rotation speed of 150 r / min. It was then water quenched and repeatedly hot rotary forging was performed for 3 passes to obtain a Φ2 mm wire blank.

[0026] (3) Stretching:

[0027] The wire blank in (2) was subjected to solution heat treatment at 750°C for 2 min, water quenched, and then repeatedly drawn for 3 times to obtain a wire blank with a diameter of 0.6 mm.

[0028] (4) Multi-mode high-precision stretching

[0029] The wire blank in (3) was subjected to multi-mode high-precision stretching in 5 sets of stretching dies at a stretching speed of 5 m / s to obtain a wire blank of Φ0.075 mm.

[0030] (5) Continuous annealing

[0031] The Φ0.075 mm wire billet was solution treated at a temperature of 800° C. for 2 minutes, and continuously annealed at 800° C. Finally, a Φ0.075 mm soft beryllium copper microwire was obtained. Embodiment 2:

[0032] (1) Vacuum casting:

[0033] 1.7% nickel, 0.41% silicon, 1.9% beryllium and impurities not exceeding 0.06% by mass, with the remainder being copper, are placed in a vacuum melting furnace for melting at a temperature of 1200°C. Mechanical stirring is performed during the melting process. Then, semi-continuous casting is performed to prepare a small-sized beryllium copper nickel silicon wire billet of Φ8mm and length of 0.8m.

[0034] (2) Hot rotary forging:

[0035] The wire blank in (1) was heated to 800°C in a tubular furnace, and was rotary forged using a four-die rotary forging machine at a rotation speed of 200 r / min. It was then water quenched and hot rotary forging was repeated four times to obtain a wire blank with a diameter of 1.5 mm.

[0036] (3) Stretching:

[0037] The wire blank in (2) was subjected to solution heat treatment at 800°C for 3 min, water quenched, and then repeatedly drawn 4 times to obtain a wire blank of Φ0.5 mm.

[0038] (4) Multi-mode high-precision stretching:

[0039] The wire blank in (3) was subjected to multi-mode high-precision stretching in 8 sets of stretching dies at a stretching speed of 10 m / s to obtain a wire blank of Φ0.05 mm.

[0040] (5) Continuous annealing:

[0041] The Φ0.05 mm wire billet was solution treated at a temperature of 850°C for 3 minutes and continuously annealed at 800°C. Finally, a Φ0.05 mm soft beryllium copper microwire was obtained. Embodiment three:

[0042] (1) Vacuum casting:

[0043] 1.7% nickel, 0.41% silicon, 1.9% beryllium and impurities not exceeding 0.06% by mass, with the remainder being copper, are placed in a vacuum melting furnace for melting at a temperature of 1300°C. Mechanical stirring is performed during the melting process, and then semi-continuous casting is performed to prepare a small-sized beryllium copper nickel silicon wire billet of Φ10mm and length of 1.5m.

[0044] (2) Hot rotary forging:

[0045] The wire blank in (1) was heated to 850°C in a tubular furnace, and was rotary forged using a four-die rotary forging machine at a rotation speed of 300 r / min. It was then water quenched and hot rotary forging was repeated 5 times to obtain a wire blank with a diameter of 1 mm.

[0046] (3) Stretching:

[0047] The wire blank in (2) was subjected to solution heat treatment at 850°C for 4 min, water quenched, and then repeatedly drawn 6 times to obtain a wire blank with a diameter of 0.3 mm.

[0048] (4) Multi-mode high-precision stretching:

[0049] The wire blank in (3) was subjected to multi-mode high-precision stretching in 10 sets of stretching dies at a stretching speed of 20 m / s to obtain a wire blank of Φ0.03 mm.

[0050] (5) Continuous annealing:

[0051] The Φ0.03 mm wire billet was solution treated at a temperature of 900°C for 4 minutes and continuously annealed at 800°C. Finally, a Φ0.03 mm soft beryllium copper microwire was obtained.

[0052] Comparative Example:

[0053] (1) Vacuum casting:

[0054] 1.9% beryllium and impurities not exceeding 0.06% in total, with the remainder being copper, are placed in a vacuum melting furnace for melting at a temperature of 1200°C. Mechanical stirring is performed during the melting process, and then semi-continuous casting is performed to prepare a small-sized beryllium copper nickel silicon wire billet of Φ8mm and length of 0.8m.

[0055] (2) Hot rotary forging:

[0056] The wire blank in (1) was heated to 800°C in a tubular furnace, and was rotary forged using a four-die rotary forging machine at a rotation speed of 200 r / min. It was then water quenched and hot rotary forging was repeated four times to obtain a wire blank with a diameter of 1.5 mm.

[0057] (3) Stretching:

[0058] The wire blank in (2) was subjected to solution heat treatment at 800°C for 3 min, water quenched, and then repeatedly drawn 4 times to obtain a wire blank of Φ0.5 mm.

[0059] (4) Multi-mode high-precision stretching:

[0060] The wire blank in (3) was subjected to multi-mode high-precision stretching in 8 sets of stretching dies at a stretching speed of 10 m / s to obtain a wire blank of Φ0.05 mm.

[0061] (5) Continuous annealing:

[0062] The Φ0.05 mm wire billet was solution treated at a temperature of 850°C for 3 minutes and continuously annealed at 800°C. Finally, a Φ0.05 mm soft beryllium copper microwire was obtained.

[0063] The tensile strength test was carried out on each embodiment and comparative example according to GB / T228.1-2021. The results are shown in Table 1:

[0064] Table 1 Comparison of tensile strength of beryllium copper microwires with Ni and Si added

[0065]

[0066] Note: TD04: solution heat treatment and cold working to hard state, TH04: hard state and precipitation heat treatment.

[0067] In the present invention, due to the addition of nickel and silicon, after the material is subjected to solid solution quenching and aging treatment, Ni and Si atoms are precipitated from the copper matrix to form nano-scale delta-Ni2Si intermetallic compounds. The nano-scale precipitated particles interact with dislocations and hinder the movement of dislocations, thereby improving the strength of the material. Since the solute elements are precipitated from the Cu matrix, the scattering effect of the copper matrix on electrons is weakened, thereby improving the electrical conductivity. Therefore, the addition of Ni and Si can enable the alloy to obtain higher strength while maintaining excellent electrical and thermal conductivity.

[0068] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing beryllium copper microwires with low stress relaxation performance, characterized in that: The method is: 1) Vacuum casting: 0.2% to 2% nickel, 0.05% to 0.5% silicon, 1.8% to 2% beryllium and impurities not exceeding 0.06% by weight, and the rest is copper; The wire is placed in a vacuum melting furnace for melting at a temperature of 1100°C to 1300°C, stirred during the melting process, and then semi-continuously cast to prepare a beryllium copper nickel silicon wire billet with a diameter of 5 to 10 mm and a length of 0.5 to 1.2 m; 2) Hot rotary forging: heat the wire blank in 1) to 750℃~850℃, use a rotary forging machine to perform rotary forging, then water quench, and repeatedly perform hot rotary forging to obtain a wire blank of Φ1~2mm; 3) Stretching: The wire blank in 2) is subjected to solution heat treatment at a temperature of 750-850°C for 2-4 minutes, and after water quenching, it is repeatedly drawn to obtain a wire blank of Φ0.3-0.6 mm; 4) Multi-mode stretching: The wire blank in 3) is subjected to multi-mode stretching in a stretching die at a stretching speed of 5-20 m / s to obtain a wire blank of Φ0.03-0.075 mm; 5) Continuous annealing: The wire billet of Φ0.03~0.075mm is solution treated at a temperature of 800℃~900℃, and then continuously annealed at a temperature of 800℃, and finally a soft beryllium copper microwire of Φ0.03~0.075mm is obtained. The grain size of the beryllium copper microwire with Ni and Si added is in the range of 600-800nm.

2. The method for preparing beryllium copper microwires with low stress relaxation performance according to claim 1, characterized in that: The mass percentages of 1) are 1.7% nickel, 0.41% silicon, 1.9% beryllium and impurities not exceeding 0.06% in total, and the remainder is copper.

3. The method for preparing beryllium copper microwires with low stress relaxation performance according to claim 1, characterized in that: The rotary forging machine in the above 2) rotates at a speed of 150-300 r / min, followed by water quenching, and then 3-5 passes of repeated hot rotary forging to obtain a wire blank of Φ1-2 mm.

4. The method for preparing beryllium copper microwires with low stress relaxation performance according to claim 1, characterized in that: In the above 3), a solution heat treatment is performed for 2-4 minutes, and after water quenching, 3-6 passes of repeated drawing are performed to obtain a wire blank with a diameter of 0.3-0.6 mm.

5. The method for preparing beryllium copper microwires with low stress relaxation performance according to claim 1, characterized in that: In the above 5), a solution treatment is performed for 2-4 minutes, and then a continuous annealing is performed at a temperature of 800° C., and finally a soft beryllium copper microwire of Φ0.03-0.075 mm is obtained.

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