Gold-silver-copper-manganese alloy wire and forming method thereof

Abstract

The invention belongs to the technical field of electric contact material and precious metal alloy processing, and particularly relates to a gold-silver-copper-manganese alloy wire and a forming method thereof, gold and silver are used as a matrix, copper manganese and rare earth element yttrium are added, a water-cooling copper mold casting process is adopted, and after homogenization treatment, rolling and cold drawing forming, stress relief annealing, cleaning and electrolytic polishing are carried out on the alloy wire. The gold-silver-copper-manganese alloy wire prepared by the invention not only has high tensile strength and longer service life, but also has excellent conductivity and important market value.

Description

Technical Field

[0001] This invention relates to the field of precious metal-based alloy materials, specifically to a gold-silver-copper-manganese alloy wire and its forming method. Background Technology

[0002] In the field of electronics and electrical engineering, electrical contact materials are the core of realizing the circuit switching function and are widely used in components such as relays and connectors. Their performance directly affects key indicators such as contact resistance, wear resistance, corrosion resistance, and service life of equipment. Traditional electrical contact materials mainly include: pure silver, silver-based alloys (such as AgCdO and AgNi), gold and its alloys, copper-based alloys, or gold-plated wire. Pure silver has excellent conductivity, but it is prone to sulfidation, wear, and has poor arc resistance; silver-based alloys (such as AgCdO) improve wear resistance and weldability to some extent, but CdO contains toxic cadmium and has problems with arc erosion and contact resistance fluctuations, and is being phased out; gold and its alloys have excellent corrosion resistance and sulfidation resistance, but are expensive, and pure gold wire has low strength, making it difficult to meet the requirements for structural stability and elastic contacts; copper-based alloys or gold-plated wires are low in cost, but have poor oxidation resistance and conductivity stability, making them unsuitable for high-end precision contact applications. Therefore, wires based on precious metals and achieving synergistic performance through multi-element alloying have attracted attention. Gold-silver-copper-manganese alloy wires are produced by adding copper and manganese to gold or silver as a base, ensuring excellent conductivity while also improving strength and wear resistance. However, due to the different melting points of gold, silver, copper, and manganese, gold-silver-copper-manganese ingots cast using existing processes have numerous defects, including severe dendrite segregation, which is difficult to completely eliminate even after multiple rolling processes, resulting in a low yield of gold-silver-copper-manganese alloy wires.

[0003] In conclusion, addressing casting defects in gold-silver-copper-manganese alloys and improving the yield rate of alloy wires are of paramount importance for increasing the scale and marketability of gold-silver-copper-manganese alloy wires. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a gold-silver-copper-manganese alloy wire and its forming method. Using gold and silver as the base material, copper, manganese, and the rare earth element yttrium are added. A water-cooled copper mold casting process is employed. After homogenization treatment, rolling, and cold drawing, the wire undergoes stress-relief annealing, followed by cleaning and electrolytic polishing. The resulting gold-silver-copper-manganese alloy wire not only possesses high tensile strength and a long service life but also excellent electrical conductivity, giving it significant market value.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention employs six steps: (1) batching and smelting, (2) water-cooled copper mold casting, (3) homogenization treatment, (4) hot rolling, (5) cold drawing, and (6) post-treatment, to manufacture gold-silver-copper-manganese alloy wires that meet the requirements. The steps include:

[0007] Step (1): Batching and smelting;

[0008] The alloy wire is composed of the following components by weight: 15-50 parts gold, 20-70 parts silver, 5-30 parts copper, 0.5-5 parts manganese, and 0.01-0.5 parts silver-yttrium alloy. High-purity gold, silver, copper, manganese, and silver-yttrium alloy are weighed according to the above proportions. Under vacuum, the gold, silver, and copper are first added to a melting furnace in the specified proportions to melt. The manganese is added while maintaining the melt temperature above 1200℃. Finally, the silver-yttrium alloy is added. After stirring for 30-120 seconds, a uniform alloy melt is obtained.

[0009] Step (2): Water-cooled copper mold casting;

[0010] The alloy melt in step (1) is quickly and smoothly poured into a cylindrical copper mold through an automatic casting system. The outer wall of the mold is cooled by circulating water to keep the cooling rate of the alloy liquid at 95-105℃ / s. After cooling to room temperature, the mold is demolded and the gate, riser and surface oxide scale are removed.

[0011] Step (3): Homogenization process;

[0012] After removing defects such as risers, shrinkage cavities, and gating channels from the ingot obtained in step (2), it is placed in a vacuum heat treatment furnace for homogenization treatment. The homogenization treatment temperature is 700℃-850℃ and the homogenization treatment time is 2-12h.

[0013] Step (4): Hot rolling forming;

[0014] The ingot that has been homogenized in step (3) is placed in a vacuum furnace for heating. The initial rolling temperature is ≥800℃ and the final rolling temperature is ≥700℃. The initial reduction of the rolling is small and gradually increases. The total reduction rate can reach 50%~80%. The rolling passes are 2-4. After rolling into thin bars, the bars are air-cooled and pickled to remove surface contaminants.

[0015] Step (5): Cold drawing forming;

[0016] After surface pretreatment of the rolled bar in step (4), it is placed in a mold for cold drawing. The deformation amount of the first pass is controlled at 5%-10%, and the deformation amount is gradually increased in subsequent passes. The deformation amount of a single pass is ≤20%, and the drawing speed is 0.5-2m / s. Work hardening will occur after the drawing deformation amount increases. When the cumulative cold drawing deformation amount exceeds 50%, annealing softening treatment is required. When the material reaches close to the target diameter, the last 1-2 passes of drawing are carried out. At this time, the deformation amount is controlled at 3%~10% to ensure dimensional accuracy and surface quality, and finally the alloy wire of the required size is obtained.

[0017] Step (6): Post-processing;

[0018] The cold-drawn wire undergoes significant plastic deformation and contains considerable residual stress. To stabilize the wire's dimensions, it needs to undergo stress-relief annealing at 300-500℃ for 1-2 hours under a nitrogen atmosphere. After stress-relief annealing, the wire surface is cleaned and electropolished to improve its surface finish.

[0019] Preferably, in step (1), the melt temperature is 1200℃-1280℃ to avoid uneven composition of the molten liquid due to a large temperature range, the melting time is 45-90min, and the mass percentage of yttrium in the silver-yttrium alloy is 0.5-1.5%.

[0020] Preferably, in step (2), the casting temperature of the alloy melt is 1150℃-1250℃, the casting method is gravity casting, and the temperature of the circulating water on the outer wall of the mold is less than 40℃, so as to ensure that the outer wall of the copper mold is always in a low temperature state and avoid overheating that leads to a decrease in mold life or casting defects.

[0021] Water-cooled copper mold casting process can produce ingots with fine grains, uniform structure and less segregation, which is suitable for casting precious metal-based wires such as gold, silver, copper and manganese alloys.

[0022] Preferably, in step (3), the homogenization treatment time is 2-12 hours. The homogenization treatment time needs to be determined according to the size of the ingot. When the ingot diameter is between 30-50 mm, the homogenization treatment time is 6-12 hours; when the ingot diameter is between 10-30 mm, the homogenization treatment time is 4-7 hours; and when the diameter is less than 10 mm, the homogenization treatment time is 2-5 hours.

[0023] Preferably, in step (4), the rolling speed is 0.1-1 m / s, and after 2-3 passes of rolling, annealing is performed to eliminate internal stress. The annealing temperature is 200℃-400℃, the annealing time is 1-3 h, the protective atmosphere is vacuum, and the furnace is cooled.

[0024] Preferably, in step (4), the acid washing should use a dilute nitric acid aqueous solution with a concentration of 0.06-0.3 mol / L, the acid washing time should be 5-120 s, and the acid washing should be immediately followed by rinsing with deionized water.

[0025] Preferably, in step (5), the pretreatment method is phosphating, which helps to form a lubricating underlayer, improves the drawing lubrication effect, and protects the surface to prevent oxidation and scratches during the drawing process. The phosphating treatment uses a copper phosphate aqueous solution with a pH of 2-4, a mass concentration of 3-5%, and a temperature of 50-70℃. The treatment time is 1-5 minutes. After treatment, the wire needs to be washed with water, dried, and coated with a lubricant to facilitate cold drawing of the alloy wire.

[0026] Preferably, in step (5), when the cold drawing deformation is too large, work hardening will occur, causing the material to become hard and brittle. At this time, annealing softening treatment is required. The annealing softening treatment temperature is 500℃-700℃, the time is 0.5-2h, the protective atmosphere is vacuum, and the furnace is cooled.

[0027] Preferably, in step (6), ultrasonic cleaning is performed before electropolishing. The electrolyte is a phosphoric acid aqueous solution with a mass fraction of 60-80%. 2g / L of glycerol can be added to alleviate the corrosive effect of electropolishing on the wire. The electropolishing temperature is 40℃-60℃, the voltage is 5-10V, and the time is 20-60s.

[0028] This solution also proposes a gold-silver-copper-manganese alloy wire prepared by the above-described process.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] The gold-silver-copper-manganese alloy wire and its forming method of the present invention are based on precious metals, with the addition of copper, manganese and rare earth elements. This avoids the disadvantages of using a single precious metal as the alloy wire, which not only improves the strength of the alloy wire and extends the service life of the wire, but also optimizes the conductivity of the alloy wire. Detailed Implementation

[0031] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The materials used in the embodiments and comparative examples are:

[0033] Gold 99.99% purity, silver 99.99% purity, copper 99.99% purity, manganese 99.99% purity.

[0034] In silver-yttrium alloys, the mass percentage of yttrium is 0.5-1.5%.

[0035] The diameter of the ingot is 40mm;

[0036] The lubricant in step (5) is sodium stearate.

[0037] Example 1:

[0038] A method for forming a gold-silver-copper-manganese alloy wire includes the following steps:

[0039] Step (1): Batching and smelting;

[0040] Weigh out the following components by weight: 32.5 parts gold, 45 parts silver, 17.5 parts copper, 2.75 parts manganese, and 0.255 parts silver-yttrium alloy. Under vacuum, first add the gold, silver, and copper to the melting furnace in the specified proportions and melt them. Maintain the melt temperature at 1250°C and add the manganese. Finally, add the silver-yttrium alloy and stir for 75 seconds to obtain a homogeneous alloy melt. The melting time is 67.5 minutes.

[0041] Step (2): Water-cooled copper mold casting;

[0042] The alloy melt from step (1) is poured into a copper mold. The outer wall of the mold is cooled by circulating water to keep the cooling rate of the alloy liquid at 100℃ / s. After cooling to room temperature, the mold is demolded and the gate, riser and surface oxide scale are removed. The casting temperature of the alloy melt is 1200℃ and the casting method is gravity casting. The temperature of the circulating water on the outer wall of the mold is less than 40℃.

[0043] Step (3): Homogenization process;

[0044] After removing defects such as risers, shrinkage cavities, and gating channels from the ingot obtained in step (2), it is placed in a vacuum heat treatment furnace for homogenization treatment. The homogenization treatment temperature is 775℃ and the homogenization treatment time is 8h.

[0045] Step (4): Hot rolling forming;

[0046] The ingot that has undergone homogenization in step (3) is placed in a vacuum furnace for heating. The initial rolling temperature is 810℃, the final rolling temperature is 710℃, the total reduction rate is 65%, and the rolling passes are 3. After rolling into bars, the bars are air-cooled and pickled to obtain bars. The rolling speed is 0.55m / s, and it needs to be rolled 3 times. After rolling 2 passes, annealing is performed. The annealing temperature is 300℃, the annealing time is 2h, the protective atmosphere is vacuum, and the bars are cooled with the furnace. The pickling acid is a 0.18mol / L dilute nitric acid aqueous solution, and the pickling time is 62.5s.

[0047] Step (5): Cold drawing forming;

[0048] After surface pretreatment, the rolled bar from step (4) is placed in a die for cold drawing:

[0049] The initial cold drawing deformation is controlled at 7.5%, and the deformation is gradually increased in subsequent draws, with a single draw deformation ≤20%. The drawing speed is 1.25 m / s. When the cumulative cold drawing deformation reaches 50%, annealing and softening treatment is required. When the material reaches close to the target diameter, the final drawing pass is performed, at which point the deformation is controlled at 6.5%, ultimately yielding the alloy wire of the required size. The bar surface pretreatment method is phosphating, using a copper phosphate aqueous solution with a pH of 3, a mass concentration of 4%, and a temperature of 60℃ for 3 minutes. After treatment, the bar is washed with water, dried, and finally coated with a lubricant to complete the bar surface pretreatment. The annealing and softening treatment temperature is 600℃ for 1.25 hours, the protective atmosphere is vacuum, and the bar is cooled in the furnace.

[0050] Step (6): Post-processing;

[0051] Stress-relief annealing was completed at 400℃ for 1.5 hours under a nitrogen atmosphere. After stress-relief annealing, the wire surface was cleaned and electropolished to obtain a gold-silver-copper-manganese alloy wire. The electrolyte in the electropolishing process was a 70% (w / w) phosphoric acid aqueous solution and 2 g / L glycerol. The electropolishing temperature was 50℃, the voltage was 7.5V, and the time was 40 seconds.

[0052] Example 2:

[0053] A method for forming a gold-silver-copper-manganese alloy wire includes the following steps:

[0054] Step (1): Batching and smelting;

[0055] Weigh out 15 parts gold, 20 parts silver, 5 parts copper, 0.5 parts manganese, and 0.01 parts silver-yttrium alloy by weight. In a vacuum environment, first add gold, silver, and copper to a melting furnace in proportion and melt them. Keep the melt temperature at 1280℃ and add manganese. Finally, add the silver-yttrium alloy and stir for 30 seconds to obtain a uniform alloy melt. The melting time is 45 minutes.

[0056] Step (2): Water-cooled copper mold casting;

[0057] The alloy melt in step (1) is poured into a copper mold. The outer wall of the mold is cooled by circulating water to keep the cooling rate of the alloy liquid at 95℃ / s. After cooling to room temperature, the mold is demolded and the gate, riser and surface oxide scale are removed. The casting temperature of the alloy melt is 1150℃ and the casting method is gravity casting. The temperature of the circulating water on the outer wall of the mold is less than 40℃.

[0058] Step (3): Homogenization process;

[0059] After removing defects such as risers, shrinkage cavities, and gating channels from the ingot obtained in step (2), it is placed in a vacuum heat treatment furnace for homogenization treatment. The homogenization treatment temperature is 700℃ and the homogenization treatment time is 7h.

[0060] Step (4): Hot rolling forming;

[0061] The homogenized ingot from step (3) is placed in a vacuum furnace for heating. The initial rolling temperature is 800℃, the final rolling temperature is 700℃, the total reduction rate is 50%, and the rolling passes are 2. After rolling into bars, the bars are air-cooled and pickled to obtain bars. The rolling speed is 0.1m / s, and the bars need to be rolled 3 times. After rolling 2 passes, the bars are annealed at 200℃ for 1 hour in a vacuum atmosphere. The bars are cooled in the furnace. The pickling acid is a 0.06mol / L dilute nitric acid solution for 5 seconds.

[0062] Step (5): Cold drawing forming;

[0063] After surface pretreatment, the rolled bar from step (4) is placed in a die for cold drawing:

[0064] The initial cold drawing deformation is controlled at 5%, and the deformation is gradually increased in subsequent draws, with a single draw deformation ≤20%. The drawing speed is 0.5 m / s. When the cumulative cold drawing deformation reaches 50%, annealing and softening treatment is required. When the material reaches close to the target diameter, the final drawing pass is performed, at which point the deformation is controlled at 3%, ultimately obtaining the alloy wire of the required size. The surface pretreatment of the bar is phosphating, using a copper phosphate aqueous solution with a pH of 2, a mass concentration of 3%, and a temperature of 50°C for 1 minute. After treatment, the bar is washed with water, dried, and finally coated with a lubricant to complete the surface pretreatment. The annealing and softening treatment is performed at 500°C for 0.5 hours under a vacuum atmosphere, with furnace cooling.

[0065] Step (6): Post-processing;

[0066] Stress-relief annealing was completed at 300℃ for 1 hour under a nitrogen atmosphere. After stress-relief annealing, the wire surface was cleaned and electropolished to obtain a gold-silver-copper-manganese alloy wire. The electrolyte in the electropolishing process was a 60% (w / w) phosphoric acid aqueous solution and 2 g / L glycerol. The electropolishing temperature was 40℃, the voltage was 5V, and the time was 20s.

[0067] Example 3:

[0068] A method for forming a gold-silver-copper-manganese alloy wire includes the following steps:

[0069] Step (1): Batching and smelting;

[0070] Weigh out 50 parts gold, 70 parts silver, 30 parts copper, 5 parts manganese, and 0.5 parts silver-yttrium alloy by weight. In a vacuum environment, first add the gold, silver, and copper to the melting furnace in proportion and melt them. Keep the melt temperature at 1250℃ and add manganese. Finally, add the silver-yttrium alloy and stir for 120 seconds to obtain a uniform alloy melt. The melting time is 90 minutes.

[0071] Step (2): Water-cooled copper mold casting;

[0072] The alloy melt from step (1) is poured into a copper mold. The outer wall of the mold is cooled by circulating water to keep the cooling rate of the alloy liquid at 105℃ / s. After cooling to room temperature, the mold is demolded and the gate, riser and surface oxide scale are removed. The casting temperature of the alloy melt is 1250℃ and the casting method is gravity casting. The temperature of the circulating water on the outer wall of the mold is less than 40℃.

[0073] Step (3): Homogenization process;

[0074] After removing defects such as risers, shrinkage cavities, and gating channels from the ingot obtained in step (2), it is placed in a vacuum heat treatment furnace for homogenization treatment. The homogenization treatment temperature is 850℃ and the homogenization treatment time is 9h.

[0075] Step (4): Hot rolling forming;

[0076] The homogenized ingot from step (3) is placed in a vacuum furnace for heating. The initial rolling temperature is 810℃, the final rolling temperature is 710℃, the total reduction rate is 80%, and the rolling passes are 4. After rolling into bars, the bars are air-cooled and pickled to obtain bars. The rolling speed is 1m / s, and it needs to go through 4 rolling passes. After rolling 3 passes, annealing is performed. The annealing temperature is 400℃, the annealing time is 3h, the protective atmosphere is vacuum, and the bars are cooled with the furnace. The pickling acid is a 0.3mol / L dilute nitric acid aqueous solution, and the pickling time is 120s.

[0077] Step (5): Cold drawing forming;

[0078] After surface pretreatment, the rolled bar from step (4) is placed in a die for cold drawing:

[0079] The initial cold drawing deformation is controlled at 10%, and the deformation is gradually increased in subsequent draws, with a single draw deformation ≤20%. The drawing speed is 2 m / s. When the cumulative cold drawing deformation reaches 50%, annealing and softening treatment is required. When the material reaches a diameter close to the target diameter, the final two draws are performed, with the deformation controlled at 10% at this point, ultimately yielding the alloy wire of the required size. The bar surface pretreatment is phosphating, using a copper phosphate aqueous solution with a pH of 4, a mass concentration of 5%, and a temperature of 70°C for 5 minutes. After treatment, the bar is washed with water, dried, and finally coated with a lubricant to complete the bar surface pretreatment. The annealing and softening treatment is performed at 700°C for 2 hours under a vacuum atmosphere, with furnace cooling.

[0080] Step (6): Post-processing;

[0081] Stress-relief annealing was completed at 500℃ for 2 hours under a nitrogen atmosphere. After stress-relief annealing, the wire surface was cleaned and electropolished to obtain a gold-silver-copper-manganese alloy wire. The electrolyte in the electropolishing process was an 80% (w / w) phosphoric acid aqueous solution and 2 g / L glycerol. The electropolishing temperature was 60℃, the voltage was 10V, and the time was 60s.

[0082] Example 4:

[0083] A method for forming a gold-silver-copper-manganese alloy wire includes the following steps:

[0084] Step (1): Batching and smelting;

[0085] Weigh out 40 parts gold, 60 parts silver, 25 parts copper, 4 parts manganese, and 0.4 parts silver-yttrium alloy by weight. In a vacuum environment, first add the gold, silver, and copper to the melting furnace in proportion and melt them. Keep the melt temperature at 1280℃ and add manganese. Finally, add the silver-yttrium alloy and stir for 100 seconds to obtain a uniform alloy melt. The melting time is 80 minutes.

[0086] Step (2): Water-cooled copper mold casting;

[0087] The alloy melt from step (1) is poured into a copper mold. The outer wall of the mold is cooled by circulating water to keep the cooling rate of the alloy liquid at 98℃ / s. After cooling to room temperature, the mold is demolded and the gate, riser and surface oxide scale are removed. The casting temperature of the alloy melt is 1220℃ and the casting method is gravity casting. The temperature of the circulating water on the outer wall of the mold is less than 40℃.

[0088] Step (3): Homogenization process;

[0089] After removing defects such as risers, shrinkage cavities, and gating channels from the ingot obtained in step (2), it is placed in a vacuum heat treatment furnace for homogenization treatment. The homogenization treatment temperature is 820℃ and the homogenization treatment time is 8.5h.

[0090] Step (4): Hot rolling forming;

[0091] The homogenized ingot from step (3) is placed in a vacuum furnace for heating. The initial rolling temperature is 810℃, the final rolling temperature is 700℃, the total reduction rate is 75%, and the rolling passes are 3. After rolling into bars, the bars are air-cooled and pickled to obtain bars. The rolling speed is 0.8m / s, and it needs to be rolled 4 times. After rolling 3 times, annealing is performed. The annealing temperature is 350℃, the annealing time is 2.5h, the protective atmosphere is vacuum, and the bars are cooled with the furnace. The pickling acid is a 0.25mol / L dilute nitric acid aqueous solution, and the pickling time is 100s.

[0092] Step (5): Cold drawing forming;

[0093] After surface pretreatment, the rolled bar from step (4) is placed in a die for cold drawing:

[0094] The initial cold drawing deformation is controlled at 8%, and the deformation is gradually increased in subsequent draws, with a single draw deformation ≤20%. The drawing speed is 1.5 m / s. When the cumulative cold drawing deformation reaches 51%, annealing and softening treatment is required. When the material reaches a diameter close to the target diameter, the final two draws are performed, with the deformation controlled at 8% at this point, ultimately yielding alloy wire of the required size. The bar surface pretreatment is phosphating, using a copper phosphate aqueous solution with a pH of 3.5, a mass concentration of 4.5%, and a temperature of 65°C for 4 minutes. After treatment, the bar is washed with water, dried, and finally coated with a lubricant to complete the bar surface pretreatment. The annealing and softening treatment is performed at 650°C for 1.5 hours under a vacuum atmosphere, with furnace cooling.

[0095] Step (6): Post-processing;

[0096] Stress-relief annealing was completed at 450℃ for 1.8 hours under a nitrogen atmosphere. After stress-relief annealing, the wire surface was cleaned and electropolished to obtain a gold-silver-copper-manganese alloy wire. The electrolyte in the electropolishing process was a 75% (w / w) phosphoric acid aqueous solution and 2 g / L glycerol. The electropolishing temperature was 55℃, the voltage was 9V, and the time was 50s.

[0097] Comparative Example 1

[0098] The difference from Example 1 is that no silver-yttrium alloy was added in step (1).

[0099] Comparative Example 2

[0100] The difference from Example 1 is that in step (1), all the alloys are directly added together for smelting.

[0101] Comparative Example 3

[0102] The difference from Example 1 is that the alloy wire composition in step (1) is: 60 parts gold, 80 parts silver, 40 parts copper, 5 parts manganese, and 1 part silver-yttrium alloy.

[0103] Comparative Example 4

[0104] The difference from Example 1 is that the alloy wire composition in step (1) is: 10 parts gold, 10 parts silver, 2 parts copper, 0.2 parts manganese, and a total of 0.0005 parts silver-yttrium alloy.

[0105] Comparative Example 5

[0106] The difference from Example 1 is that the water-cooled copper mold casting process was not used in the corresponding step (2), but ordinary sand casting was used instead.

[0107] Comparative Example 6

[0108] The difference from Example 1 is that the cooling rate of the alloy liquid in step (2) is 10℃ / s.

[0109] Comparative Example 7

[0110] The difference from Example 1 is that the homogenization time in step (3) is 15h.

[0111] Comparative Example 8

[0112] The difference from Example 1 is that the reduction amount in the initial rolling stage of step (4) is 10%.

[0113] Comparative Example 9

[0114] The difference from Example 1 is that the drawing rate in step (5) is 3 m / s.

[0115] Comparative Example 10

[0116] The difference from Example 1 is that no annealing softening treatment was performed in the corresponding step (5).

[0117] Comparative Example 11

[0118] The difference from Example 1 is that step (4) does not involve phosphating.

[0119] Comparative Example 12

[0120] The difference from Example 1 is that the deformation per pass is 22%.

[0121] Performance testing:

[0122] Wire diameter: Non-contact measurement is performed using a laser diameter gauge;

[0123] Tensile properties: Refer to the test methods for fine wires in ASTM E8 standard to test tensile strength (MPa) and elongation after fracture (%).

[0124] Resistivity measurement: DC four-probe method for measuring the resistivity of a thin wire;

[0125] Fatigue resistance test: repeated bending fatigue test.

[0126] The test results of the examples and comparative examples are shown in Table 1.

[0127] Table 1. Detection results of the examples and comparative examples.

[0128] Group Wire diameter (mm) Tensile strength (MPa) Elongation after fracture (%) Resistivity (μΩ・cm) Fatigue resistance life (times) Example 1 0.50±0.01 510 10.5 3 28000 Example 2 0.50±0.01 460 9.2 3.2 23000 Example 3 0.50±0.01 540 8.8 2.9 30000 Example 4 0.50±0.01 525 9.8 2.8 27000 Comparative Example 1 0.50±0.01 380 7.5 3.4 12000 Comparative Example 2 0.51±0.02 410 6.8 3.5 14000 Comparative Example 3 0.52±0.02 430 5.2 3.6 11000 Comparative Example 4 0.49±0.02 350 8 3.3 10000 Comparative Example 5 0.53±0.03 355 4.5 3.8 8000 Comparative Example 6 0.51±0.02 400 7 3.4 15000 Comparative Example 7 0.50±0.01 420 9 3.1 18000 Comparative Example 8 0.52±0.02 480 6.2 3.2 16000 Comparative Example 9 0.53±0.02 490 5.8 3.3 13000 Comparative Example 10 0.48±0.02 580 4 3.2 9000 Comparative Example 11 0.54±0.03 450 7.8 3.5 10000 Comparative Example 12 0.52±0.02 500 3.5 3.3 7000

[0129] Examples 1-4 of the gold-silver-copper-manganese alloy wire and its forming method have absolute advantages over comparative examples 1-12 in terms of tensile strength, elongation after fracture, resistivity, and bending fatigue life.

[0130] The reason why the embodiment can achieve excellent tensile strength, plasticity, electrical conductivity and fatigue resistance is that it constructs a uniform and refined microstructure through scientific composition design and process coordination: gold and silver are used as the matrix, copper and manganese form a dispersed strengthening phase, rare earth yttrium plays a grain refinement role and inhibits dendrite growth; gold, silver and copper are melted first, and then manganese and silver yttrium are added to avoid premature oxidation of manganese and compositional segregation. The high cooling rate of the water-cooled copper mold further inhibits segregation and refines the grains; homogenization treatment eliminates internal stress and compositional gradient in the ingot; the initial reduction of the gradient rolling is small and gradually increases; the initial deformation of the cold drawing is small and the cumulative deformation exceeds 50%. Annealing softening controls work hardening and avoids the generation of internal microcracks; phosphating treatment ensures interface lubrication and surface quality during drawing, and finally forms a dense, defect-free and uniform microstructure. The performance disadvantages of the comparative examples all stemmed from deviations from the aforementioned core design: Comparative Example 1, lacking the addition of silver-yttrium alloy, lacked the grain-refining effect of rare-earth yttrium, resulting in coarse grains and poor microstructure uniformity, leading to a significant decrease in strength and fatigue resistance; Comparative Example 2 used simultaneous melting of all alloys, but manganese, with its high melting point and easy oxidation, prematurely melted with low-melting-point gold and silver, easily generating oxide impurities and causing compositional inhomogeneity, weakening the strengthening effect and increasing resistivity; Comparative Example 3 had an excessively high proportion of gold, silver, copper, and silver-yttrium, forming metallogenic agglomerates or brittle intermetallic compounds. Disruption of microstructure continuity leads to a sharp drop in plasticity and fatigue resistance; Comparative Example 4 shows an excessively low proportion of noble metal matrix and functional elements, with excessive copper and manganese forming a large number of brittle phases, weakening the matrix support capacity and significantly reducing strength and fatigue life; Comparative Example 5 uses sand casting instead of water-cooled copper molds, resulting in a sharp drop in cooling rate, severe dendrite segregation, and a loose microstructure, generating numerous stress concentration points, leading to a comprehensive decline in overall mechanical properties and electrical conductivity; Comparative Example 6 has a cooling rate of only 10℃ / s, which, although better than sand casting, still cannot suppress grain growth and slight segregation, resulting in a refined microstructure. The effects were insufficient, with strength and fatigue resistance weaker than the examples; in Comparative Example 7, the homogenization treatment time was too long, and excessive heat preservation led to abnormal grain growth, the refinement advantage disappeared, strength decreased, and stress was prone to concentration during fatigue; in Comparative Example 8, the initial reduction in rolling was too large, the ingot was not sufficiently softened, and microcracks were easily generated on the surface and inside, which could not be completely eliminated in subsequent processing, resulting in a decrease in plasticity and fatigue resistance; in Comparative Example 9, the drawing speed was too fast, and the friction between the die and the wire generated heat, causing surface scratches, and uneven deformation caused internal stress concentration, reducing plasticity and fatigue life. Low; Comparative Example 10 did not undergo annealing softening treatment, work hardening continued to accumulate, the material brittleness increased, plasticity decreased sharply, and it was prone to fracture due to stress concentration during fatigue; Comparative Example 11 did not undergo phosphating treatment, and lacked a lubricating underlayer during drawing, resulting in scratch defects on the surface, which not only increased resistivity, but also made the surface defects into fatigue crack sources, shortening the life; Comparative Example 12 had a single-pass deformation exceeding the critical value of 20%, and the wire exceeded the plastic deformation limit, generating microcracks, destroying the integrity of the structure, and ultimately leading to a significant deterioration in plasticity and fatigue resistance.

[0131] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method of forming a gold silver copper manganese alloy wire, characterized by, The method comprises the following steps Step (1): batching and smelting According to weight parts, 15-50 parts of gold, 20-70 parts of silver, 5-30 parts of copper, 0.5-5 parts of manganese, and 0.01-0.5 parts of silver-yttrium alloy in total are weighed, gold, silver and copper are first added into a smelting furnace for melting under a vacuum environment, manganese is added when the temperature of the melt is kept above 1200 DEG C, and finally the silver-yttrium alloy is added, and after stirring for 30-120 s, an alloy melt with uniform composition is obtained; Step (2): water-cooled copper mold casting The alloy melt in step (1) is poured into a copper mold, the outer wall of the mold is cooled by circulating water, the cooling rate of the alloy liquid is kept at 95-105 DEG C / s, and after cooling to room temperature, demolding treatment is performed, and the sprue, riser and surface oxide skin are removed; Step (3): homogenization treatment After removing the defective parts such as riser, shrinkage and sprue of the cast ingot obtained in step (2), the cast ingot is placed in a vacuum heat treatment furnace for homogenization treatment, the homogenization treatment temperature is 700 DEG C-850 DEG C, and the homogenization treatment time is 2-12 h; Step (4): hot rolling forming The cast ingot subjected to homogenization treatment in step (3) is heated in a vacuum furnace, the starting rolling temperature is equal to or greater than 800 DEG C, the final rolling temperature is equal to or greater than 700 DEG C, the total reduction is 50%-80%, the rolling passes are 2-4, the rolled bar is air-cooled, pickled, and a bar is obtained; Step (5): cold drawing forming The bar formed by rolling in step (4) is pretreated on the surface and then placed in a mold for cold drawing: The deformation amount of the first pass is controlled to be 5%-10%, the deformation amount is gradually increased in subsequent passes, the single-pass deformation amount is less than or equal to 20%, the drawing speed is 0.5-2 m / s, and when the cumulative cold drawing deformation amount exceeds 50%, annealing softening treatment is required, and the last 1-2 passes are drawn when the material approaches the target diameter, at this time, the deformation amount is controlled to be 3%-10%, and finally the alloy wire with the required size is obtained; Step (6): post-treatment The stress relief annealing treatment is completed at 300-500 DEG C for 1-2 h, the protective atmosphere is nitrogen, the surface of the wire is cleaned and electrolytic polishing treatment is performed after the stress relief annealing treatment, and a gold-silver-copper-manganese alloy wire is obtained.

2. The forming method of a gold silver copper manganese alloy wire according to claim 1, characterized by, In step (1), the melt temperature is 1200 DEG C-1280 DEG C, the smelting time is 45-90 min, and the mass percentage of yttrium in the silver-yttrium alloy is 0.5-1.5%.

3. The forming method of a gold silver copper manganese alloy wire according to claim 1, characterized by, In step (2), the alloy melt pouring temperature is 1150 DEG C-1250 DEG C, and the pouring method is gravity pouring; the circulating water temperature of the mold outer wall is less than 40 DEG C.

4. The forming method of a gold silver copper manganese alloy wire according to claim 1, characterized by, In step (3), the homogenization treatment time is 2-12 h.

5. The forming method of a gold silver copper manganese alloy wire according to claim 1, characterized by, In step (4), the rolling speed is 0.1-1 m / s, and 3-4 times of rolling is required, annealing treatment is performed after 2-3 passes of rolling, the annealing temperature is 200 DEG C-400 DEG C, the annealing time is 1-3 h, the protective atmosphere is vacuum, and the furnace is cooled.

6. The forming method of a gold silver copper manganese alloy wire according to claim 1, characterized by, In step (4), the acid solution for pickling is a dilute nitric acid aqueous solution with a concentration of 0.06-0.3 mol / L, and the pickling time is 5-120 s.

7. The forming method of a gold silver copper manganese alloy wire according to claim 1, characterized by, In the step (5), the surface pretreatment of the rod is phosphating treatment, the phosphating treatment uses copper phosphate aqueous solution with pH of 2-4, mass concentration of 3-5%, temperature of 50-70℃, and treatment time of 1-5 min, and then the rod is washed, dried, and finally coated with lubricant to complete the surface pretreatment of the rod.

8. The forming method of a gold silver copper manganese alloy wire according to claim 1, characterized by, In the step (5), the annealing softening treatment temperature is 500-700℃, the time is 0.5-2h, the protective atmosphere is vacuum, and the rod is cooled in the furnace.

9. The forming method of a gold silver copper manganese alloy wire according to claim 1, characterized by, In the step (6), the electrolyte in the electrolytic polishing treatment is 60-80% phosphoric acid aqueous solution and 2g / L glycerol, the electrolytic polishing temperature is 40-60℃, the voltage is 5-10V, and the time is 20-60s.

10. A gold-silver-copper-manganese alloy wire prepared by a forming method of the gold-silver-copper-manganese alloy wire according to any one of claims 1-9.