A gold silver copper manganese alloy wire and a forming method thereof

Abstract

The application belongs to the technical field of processing of electrical contact material and noble metal alloy, 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-cooled copper mold casting process is adopted, after homogenization treatment, rolling and cold-drawing forming, stress relief annealing is carried out on the gold-silver-copper-manganese alloy wire, and then the gold-silver-copper-manganese alloy wire is cleaned and electrolytic polished. The gold-silver-copper-manganese alloy wire prepared by the application not only has high tensile strength and long service life, but also has excellent electric conductivity, and has important market value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of precious metal-based alloy materials, in particular to a gold-silver-copper-manganese alloy wire and a forming method thereof. BACKGROUND

[0002] In the field of electronics and electrical appliances, electrical contact materials are the core of realizing the on-off function of circuits and are widely used in relays, connectors and other components. Their performance directly affects the key indicators of the equipment, such as contact resistance, wear resistance, corrosion resistance, service life, etc. Traditional electrical contact materials mainly include pure silver, silver-based alloys (such as AgCdO, AgNi), gold and its alloys, copper-based alloys or gold-plated wires. Pure silver has excellent electrical conductivity, but it is prone to sulfidation, wear and tear, and poor arc resistance; silver-based alloys (such as AgCdO) improve wear resistance and arc resistance to some extent, but CdO contains toxic cadmium, and there are problems of arc ablation and contact resistance fluctuation, which are being phased out; gold and its alloys have excellent corrosion resistance and sulfidation resistance, but they are expensive, and pure gold wire has low strength, making it difficult to meet the requirements of structural stability and elastic contacts; copper-based alloys or gold-plated wires have low cost, but they have poor oxidation resistance and electrical conductivity stability, making them difficult to be used in high-end precision contact scenarios. Therefore, wires made of precious metals as the base and through multi-element alloying to achieve performance synergy have attracted attention. In the condition of taking precious metals gold or silver as the base, gold-silver-copper-manganese alloy wires are prepared by adding copper and manganese, which not only ensure excellent electrical conductivity of the wires, but also improve the strength and wear resistance of the wires. Since the melting points of gold, silver, copper and manganese are different, the gold-silver-copper-manganese ingots cast by existing processes have many defects and serious dendritic segregation, which is difficult to completely eliminate even after multiple rolling, resulting in a low yield of gold-silver-copper-manganese alloy wires.

[0003] In summary, solving the casting defects in gold-silver-copper-manganese alloys and improving the yield level of alloy wires are the top priority for the scale-up and marketization of gold-silver-copper-manganese alloy wires. SUMMARY

[0004] To solve the above problems, the present application provides a gold-silver-copper-manganese alloy wire and a forming method thereof. Gold and silver are used as the base, copper, manganese and rare earth element yttrium are added, and a water-cooled copper mold casting process is adopted. After homogenization treatment, rolling and cold drawing forming, stress relief annealing is performed, and then cleaning and electrolytic polishing are carried out. The gold-silver-copper-manganese alloy wire thus prepared not only has high tensile strength and long service life, but also has excellent electrical conductivity, which has important market value.

[0005] To achieve the above purpose, the present application adopts the following technical solutions:

[0006] The present application adopts six steps: (1) batching and melting, (2) water-cooled copper mold casting, (3) homogenization treatment, (4) hot rolling forming, (5) cold drawing forming, and (6) post-treatment, to manufacture the required gold-silver-copper-manganese alloy wire, including the following steps

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

[0008] The components of the alloy wire are as follows in parts by weight: gold 15-50 parts, silver 20-70 parts, copper 5-30 parts, manganese 0.5-5 parts, and a total amount of 0.01-0.5 parts of silver-yttrium alloy; high-purity gold, silver, copper, manganese, and silver-yttrium alloy are weighed according to the above proportions, and the gold, silver, and copper are first added to a smelting furnace for melting under vacuum, the melt temperature is kept above 1200°C, manganese is added, and finally the silver-yttrium alloy is added, and after stirring for 30-120s, a homogeneous 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 pouring system, the mold outer wall is cooled by circulating water, the cooling rate of the alloy liquid is maintained at 95-105°C / s, and after cooling to room temperature, demolding treatment is performed, and the sprue, riser, and surface oxide scale are removed;

[0011] Step (3): homogenization treatment;

[0012] After removing the defective parts such as riser, shrinkage, and sprue from the ingot obtained in step (2), the ingot is placed in a vacuum heat treatment furnace for homogenization treatment, the homogenization treatment temperature is 700-850°C, and the homogenization treatment time is 2-12h;

[0013] Step (4): hot rolling;

[0014] The ingot after homogenization treatment in step (3) is heated in a vacuum furnace, the rolling temperature is ≥800°C, the final rolling temperature is ≥700°C, the initial rolling reduction is small and gradually increases, the total reduction is 50%-80%, the rolling passes are 2-4, the rolled bar is air-cooled after rolling, and the surface contaminants are removed by pickling;

[0015] Step (5): cold drawing;

[0016] The surface of the rolled bar in step (4) is pretreated and then placed in a mold for cold drawing, the deformation amount of the initial pass is controlled at 5%-10%, the deformation amount is gradually increased in subsequent passes, the single-pass deformation amount is ≤20%, the drawing speed is 0.5-2m / s, the work hardening occurs when the drawing deformation amount is large, annealing softening treatment is required when the cumulative cold drawing deformation amount exceeds 50%, the last 1-2 passes of drawing are performed when the material approaches the target diameter, the deformation amount is controlled at 3%-10% at this time to ensure the size accuracy and surface quality, and finally the alloy wire with the required size is obtained;

[0017] Step (6): post-treatment;

[0018] The cold-drawing formed wire produces large plastic deformation and has more residual stress. In order to stabilize the size of the wire, a stress relief annealing treatment is needed at 300-500 ℃ for 1-2 h, the protective atmosphere is nitrogen, and after the stress relief annealing treatment, the surface of the wire is cleaned and electrolytic polishing treatment is performed to improve the surface finish of the wire.

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

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

[0021] The water-cooled copper mold casting process can obtain an ingot with fine grains, uniform structure, and less segregation, which is suitable for casting of precious metal-based such as gold-silver-copper-manganese alloy wire.

[0022] Preferably, in step (3), the homogenization treatment time is 2-12 h. 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 h, when the ingot diameter is between 10-30 mm, the homogenization treatment time is 4-7 h, and when the diameter is less than 10 mm, the homogenization treatment time is 2-5 h.

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

[0024] Preferably, in step (4), the pickling needs to use dilute nitric acid aqueous solution with a concentration of 0.06-0.3 mol / L, the pickling time is 5-120 s, and the wire is immediately washed with deionized water after pickling.

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

[0026] As preferred, in step (5), when the cold drawing deformation is too large, work hardening phenomenon occurs, resulting in hardening and embrittlement of the material, at which 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 cooling is performed.

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

[0028] The present application also provides a gold-silver-copper-manganese alloy wire prepared by the above preparation process.

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

[0030] The gold-silver-copper-manganese alloy wire and the forming method thereof are based on a noble metal base, copper, manganese and rare earth elements are added, the shortcomings of using a single noble metal as an alloy wire are avoided, the strength of the alloy wire is improved, the service life of the wire is prolonged, and the conductivity of the alloy wire can be optimized. DETAILED DESCRIPTION

[0031] The embodiments of the present application will be described in detail by specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in the specification. Obviously, the described embodiments are part of the embodiments of the present application, but not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

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

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

[0034] In the silver-yttrium alloy, the mass percentage of yttrium in the silver-yttrium alloy is 0.5-1.5%;

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

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

[0037] Example 1:

[0038] A forming method of a gold-silver-copper-manganese alloy wire, comprising the following steps:

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

[0040] Take 32.5 parts of gold, 45 parts of silver, 17.5 parts of copper, 2.75 parts of manganese and 0.255 parts of silver-yttrium alloy by weight, first melt gold, silver and copper in the smelting furnace in a vacuum environment, keep the melt temperature at 1250℃, then add manganese, and finally add silver-yttrium alloy, stir for 75s to obtain a homogeneous alloy melt; the smelting time is 67.5min;

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

[0042] Pour the alloy melt in step (1) into a copper mold, cool the mold outer wall by circulating water to keep the cooling rate of the alloy liquid at 100℃ / s, cool to room temperature, then perform demolding treatment, and remove the sprue, riser and surface oxide scale; the alloy melt casting temperature is 1200℃, and the casting method is gravity casting; the circulating water temperature of the mold outer wall is less than 40℃;

[0043] Step (3): homogenization treatment;

[0044] After removing the defective parts such as riser, shrinkage and sprue of the ingot obtained in step (2), place it 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] Place the ingot after homogenization treatment in step (3) in a vacuum furnace for heating, the opening rolling temperature is 810℃, the final rolling temperature is 710℃, the total reduction is 65%, the rolling pass is 3, and the rod is obtained after air cooling, pickling and rolling; the rolling speed is 0.55m / s, and it needs to be rolled for 3 times, annealing treatment is performed after 2 passes of rolling, the annealing temperature is 300℃, the annealing time is 2h, the protective atmosphere is vacuum, and the furnace cooling is performed; the acid solution for pickling is 0.18mol / L dilute nitric acid solution, and the pickling time is 62.5s;

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

[0048] After the surface of the rod formed in step (4) is pretreated, it is placed in a mold for cold drawing:

[0049] The first pass deformation amount is controlled at 7.5%, and the deformation amount is gradually increased in subsequent passes, the single pass deformation amount is ≤20%, the drawing speed is 1.25 m / s, and when the cumulative cold drawing deformation amount is 50%, annealing softening treatment is needed, when the material approaches the target diameter, the last pass drawing is performed, at this time, the deformation amount is controlled at 6.5%, and the alloy wire of the required size is finally obtained; the rod surface pretreatment method is phosphating treatment, the phosphating treatment uses a copper phosphate aqueous solution with a pH of 3, a mass concentration of 4%, and a temperature of 60℃, the treatment time is 3 min, after treatment, water washing, drying, and finally coating lubricant, the rod surface pretreatment is completed; the annealing softening treatment temperature is 600℃, the time is 1.25 h, the protective atmosphere is vacuum, and the furnace cooling is performed;

[0050] Step (6): post-treatment;

[0051] The stress relief annealing treatment is completed at 400℃ for 1.5 h, the protective atmosphere is nitrogen, after the stress relief annealing treatment, the wire surface is cleaned and electrolytic polishing treatment is performed, and the gold-silver-copper-manganese alloy wire is obtained; in the electrolytic polishing treatment, the electrolyte is a phosphoric acid aqueous solution with a mass fraction of 70%, 2 g / L of glycerol, the electrolytic polishing temperature is 50℃, the voltage is 7.5 V, and the time is 40 s.

[0052] Example 2:

[0053] A forming method of a gold-silver-copper-manganese alloy wire, comprising the following steps:

[0054] Step (1): batching and melting;

[0055] According to weight parts, 15 parts of gold, 20 parts of silver, 5 parts of copper, 0.5 parts of manganese, and 0.01 parts of silver-yttrium alloy are weighed, the gold-silver-copper is first added to the melting furnace in proportion under vacuum, the melting temperature is kept at 1280℃, the manganese is added, and finally the silver-yttrium alloy is added, after stirring for 30 s, the alloy molten body with uniform composition is obtained; the melting time is 45 min;

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

[0057] The alloy molten body in step (1) is poured into a copper mold, the cooling rate of the alloy liquid is kept at 95℃ / s by circulating water cooling of the mold outer wall, after cooling to room temperature, demolding treatment is performed, and the sprue, riser and surface oxide skin are removed; the alloy molten body pouring temperature is 1150℃, and the pouring method is gravity pouring; the circulating water temperature of the mold outer wall is less than 40℃;

[0058] Step (3): homogenization treatment;

[0059] After removing the defective parts such as riser, shrinkage and sprue from the ingot obtained in step (2), the ingot 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 ingot subjected to homogenization treatment in step (3) is heated in a vacuum furnace, the starting rolling temperature is 800℃, the final rolling temperature is 700℃, the total reduction is 50%, and the rolling passes are 2 passes. After the rod is rolled and air-cooled, pickling is performed to obtain a rod. The rolling speed is 0.1 m / s, and 3 times of rolling are required. Annealing treatment is performed after 2 passes of rolling, the annealing temperature is 200℃, the annealing time is 1h, the protective atmosphere is vacuum, and the furnace cooling is performed. The pickling acid solution is 0.06 mol / L dilute nitric acid aqueous solution, and the pickling time is 5s;

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

[0063] After the rod formed by rolling in step (4) is pretreated, it is placed in a mold for cold drawing:

[0064] The deformation amount of the first pass is controlled to be 5%, and the deformation amount is gradually increased in subsequent passes. The single-pass deformation amount is ≤20%, the drawing speed is 0.5 m / s, and when the cumulative cold drawing deformation amount is 50%, annealing softening treatment is required. When the material approaches the target diameter, the last pass of drawing is performed, and the deformation amount is controlled to be 3%. Finally, the alloy wire of the required size is obtained. The rod surface pretreatment method is phosphating treatment. The phosphating treatment uses a copper phosphate aqueous solution with a pH of 2, a mass concentration of 3%, and a temperature of 50℃. The treatment time is 1 min, followed by water washing, drying, and finally coating a lubricant to complete the rod surface pretreatment. The annealing softening treatment temperature is 500℃, the time is 0.5h, the protective atmosphere is vacuum, and the furnace cooling is performed;

[0065] Step (6): post-treatment;

[0066] The stress relief annealing treatment is completed at 300℃ for 1h, and the protective atmosphere is nitrogen. After the stress relief annealing treatment, the wire surface is cleaned and subjected to electrolytic polishing treatment to obtain a gold-silver-copper-manganese alloy wire. In the electrolytic polishing treatment, the electrolyte is a phosphoric acid aqueous solution with a mass fraction of 60% and glycerol with a mass fraction of 2g / L. The electrolytic polishing temperature is 40℃, the voltage is 5V, and the time is 20s.

[0067] Example 3:

[0068] A forming method of a gold-silver-copper-manganese alloy wire, comprising the following steps:

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

[0070] Take by weight parts: gold 50 parts, silver 70 parts, copper 30 parts, manganese 5 parts, and a total of 0.5 parts of silver-yttrium alloy, in a vacuum environment, first gold, silver and copper are added to the smelting furnace in proportion to melt, keep the melt temperature at 1250℃, add manganese, finally add silver-yttrium alloy, stir for 120s, get the alloy melt with uniform composition; the smelting time is 90min;

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

[0072] The alloy melt in step (1) is poured into a copper mold, the mold outer wall is cooled by circulating water, the cooling rate of the alloy liquid is maintained at 105℃ / s, and after cooling to room temperature, demolding treatment is carried out, and the sprue, riser and surface oxide skin are removed; the alloy melt pouring temperature is 1250℃, and the pouring method is gravity pouring; the circulating water temperature of the mold outer wall is less than 40℃;

[0073] Step (3): homogenization treatment;

[0074] After removing the defects such as riser, shrinkage, sprue and other parts of the ingot obtained in step (2), place it 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] Put the ingot after homogenization treatment in step (3) in a vacuum furnace for heating, the opening rolling temperature is 810℃, the final rolling temperature is 710℃, the total reduction is 80%, the rolling pass is 4, and the rod is obtained after air cooling, pickling; the rolling speed is 1m / s, which needs to be rolled for 4 times, annealing treatment is carried out after 3 passes of rolling, the annealing temperature is 400℃, the annealing time is 3h, the protective atmosphere is vacuum, and the furnace cooling; the acid solution for pickling is 0.3mol / L dilute nitric acid aqueous solution, and the pickling time is 120s;

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

[0078] The rod after rolling in step (4) is pretreated and placed in a mold for cold drawing:

[0079] The deformation amount of the first pass is controlled at 10%, and the deformation amount of the subsequent passes is gradually increased, the single-pass deformation amount is ≤20%, the drawing speed is 2 m / s, and when the cumulative cold drawing deformation amount is 50%, annealing softening treatment is needed, when the material approaches the target diameter, the last two passes of drawing are performed, at this time the deformation amount is controlled at 10%, and finally the alloy wire of the required size is obtained; the surface pretreatment of the rod is phosphating treatment, the phosphating treatment uses a copper phosphate aqueous solution with a pH of 4, a mass concentration of 5%, and a temperature of 70℃, the treatment time is 5 min, after treatment, the rod is washed with water, dried, and finally coated with a lubricant to complete the surface pretreatment of the rod; the annealing softening treatment temperature is 700℃, the time is 2 h, the protective atmosphere is vacuum, and the rod is cooled in the furnace;

[0080] Step (6): post-treatment;

[0081] The stress relief annealing treatment is completed at 500℃ for 2 h in a nitrogen atmosphere, and after the stress relief annealing treatment, the surface of the wire is cleaned and electrolytic polishing treatment is performed to obtain the gold-silver-copper-manganese alloy wire; in the electrolytic polishing treatment, the electrolyte is an 80% phosphoric acid aqueous solution by mass fraction, 2 g / L of glycerol, the electrolytic polishing temperature is 60℃, the voltage is 10 V, and the time is 60 s.

[0082] Example 4:

[0083] A forming method of a gold-silver-copper-manganese alloy wire, comprising the following steps:

[0084] Step (1): batching and melting;

[0085] According to weight parts, 40 parts of gold, 60 parts of silver, 25 parts of copper, 4 parts of manganese, and 0.4 parts of silver-yttrium alloy in total are weighed, the gold-silver-copper is first added to the melting furnace in proportion under vacuum, the melting temperature is kept at 1280℃, the manganese is added, and finally the silver-yttrium alloy is added, after stirring for 100 s, an alloy melt with uniform composition is obtained; the melting time is 80 min;

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

[0087] The alloy melt in step (1) is poured into a copper mold, the mold outer wall is cooled by circulating water, so that the cooling rate of the alloy liquid is maintained at 98℃ / s, after cooling to room temperature, demolding treatment is performed, and the sprue, riser and surface oxide skin are removed; the alloy melt pouring temperature is 1220℃, and the pouring method is gravity pouring; the circulating water temperature of the mold outer wall is less than 40℃;

[0088] Step (3): homogenization treatment;

[0089] After removing the defective parts such as riser, shrinkage, sprue, etc. from the ingot obtained in step (2), the ingot 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 ingot subjected to homogenization treatment in step (3) is heated in a vacuum furnace, the starting rolling temperature is 810℃, the final rolling temperature is 700℃, the total reduction is 75%, and the rolling passes are 3. After the rod is rolled and air-cooled, pickling is performed to obtain a rod. The rolling speed is 0.8m / s, and 4 times of rolling are required. Annealing treatment is performed after 3 passes of rolling, the annealing temperature is 350℃, the annealing time is 2.5h, the protective atmosphere is vacuum, and the furnace cooling is performed. The acid solution for pickling is a dilute nitric acid aqueous solution with a concentration of 0.25mol / L, and the pickling time is 100s.

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

[0093] After the rod formed by rolling in step (4) is pretreated, it is placed in a mold for cold drawing:

[0094] The deformation amount of the first pass is controlled to be 8%, and the deformation amount is gradually increased in the subsequent passes. The single-pass deformation amount is ≤20%, the drawing speed is 1.5m / s, and the cumulative cold drawing deformation amount is 51%. When the material approaches the target diameter, the last 2 passes of drawing are performed, and the deformation amount is controlled to be 8%. Finally, the alloy wire with the required size is obtained. The rod surface pretreatment method is phosphating treatment. The phosphating treatment uses a copper phosphate aqueous solution with a pH of 3.5, a mass concentration of 4.5%, and a temperature of 65℃. The treatment time is 4min. After treatment, the rod is washed with water, dried, and finally coated with a lubricant to complete the rod surface pretreatment. The annealing softening treatment temperature is 650℃, the time is 1.5h, the protective atmosphere is vacuum, and the furnace cooling is performed.

[0095] Step (6): post-treatment;

[0096] The stress relief annealing treatment is completed at 450℃ for 1.8h, and the protective atmosphere is nitrogen. After the stress relief annealing treatment, the wire surface is cleaned and subjected to electrolytic polishing treatment to obtain a gold-silver-copper-manganese alloy wire. In the electrolytic polishing treatment, the electrolyte is a phosphoric acid aqueous solution with a mass fraction of 75% and glycerol with a mass fraction of 2g / L. The electrolytic polishing temperature is 55℃, the voltage is 9V, and the time is 50s.

[0097] Comparative Example 1

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

[0099] Comparative Example 2

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

[0101] Comparative Example 3

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

[0103] Comparative Example 4

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

[0105] Comparative Example 5

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

[0107] Comparative Example 6

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

[0109] Comparative Example 7

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

[0111] Comparative Example 8

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

[0113] Comparative Example 9

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

[0115] Comparative Example 10

[0116] The difference from Example 1 is that the annealing softening treatment is not performed in the corresponding step (5).

[0117] Comparative Example 11

[0118] The difference from Example 1 is that the phosphating treatment is not performed in step (4).

[0119] Comparative Example 12

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

[0121] Performance test:

[0122] Wire diameter: non-contact measurement by laser diameter gauge;

[0123] Tensile properties: tensile strength (MPa) and elongation at break (%) were measured according to the test method for fine wires in the standard ASTM E8;

[0124] Resistivity measurement: fine wire resistivity was measured by direct current four-probe method;

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

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

[0127] Table 1 Results of the tests of the examples and comparative examples

[0128] Group Wire diameter (mm) Tensile strength (MPa) Elongation at break (%) Resistivity (μΩ-cm) Fatigue 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 gold-silver-copper-manganese alloy wire and its forming method have absolute advantages over comparative examples 1-12 in terms of tensile strength, elongation at break, resistivity and bending fatigue life.

[0130] The embodiments can have excellent tensile strength, plasticity, electrical conductivity and fatigue resistance. The core is to build a uniform and refined structure through scientific component design and process synergy: gold and silver as the matrix, copper and manganese form a dispersion strengthening phase, and 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 and composition segregation of manganese; high cooling rate of water-cooled copper mold further inhibits segregation and refines grains; homogenization treatment eliminates internal stress and composition gradient of the ingot, and small reduction at the initial stage of gradient rolling and gradual increase, small deformation at the initial stage of cold drawing and cumulative deformation over 50% annealing softening control work hardening to avoid internal micro-cracks, phosphating treatment to ensure interface lubrication and surface quality during drawing, and finally form a dense, defect-free and uniform composition structure. The performance disadvantages of the comparative examples are all derived from the deviation from the above core design: comparative example 1 does not add silver yttrium alloy, lacks the grain refinement effect of rare earth yttrium, the grains are coarse and the structure is not uniform, resulting in a significant decrease in strength and fatigue resistance; comparative example 2 uses synchronous melting of all alloys, manganese has a high melting point and is easily oxidized, and is easily melted with low melting point gold and silver, which easily generates oxidation impurities and causes composition unevenness, weakening the strengthening effect and increasing the resistivity; comparative example 3 has a high proportion of gold, silver, copper and silver yttrium, forming a gold-rich phase aggregation or brittle intermetallic compound, which destroys the continuity of the structure, resulting in a sharp decrease in plasticity and fatigue resistance; comparative example 4 has a low proportion of noble metal matrix and functional elements, and an excessive amount of copper and manganese forms a large number of brittle phases, the matrix support capacity is weakened, and the strength and fatigue life are greatly reduced; comparative example 5 uses sand casting instead of water-cooled copper mold, the cooling rate is sharply reduced, the dendritic segregation is serious and the structure is loose, a large number of stress concentration points are generated, and the overall mechanical properties and electrical conductivity are decreased; comparative example 6 has a cooling rate of only 10℃ / s, which is better than sand mold but still cannot inhibit grain growth and slight segregation, the structure refinement effect is insufficient, the strength and fatigue resistance are weaker than the embodiments; comparative example 7 has a homogenization treatment time that is too long, and the excessive heat preservation causes abnormal grain growth, the refinement advantage disappears, the strength decreases and the stress is easily concentrated during fatigue; comparative example 8 has a large reduction at the initial stage of rolling, the ingot is not fully softened, and micro-cracks are easily generated on the surface and inside, which cannot be completely eliminated in subsequent processing, resulting in a decrease in plasticity and fatigue resistance; comparative example 9 has a too fast drawing speed, the friction between the mold and the wire generates heat, causing surface scratches, and uneven deformation causes internal stress concentration, reducing plasticity and fatigue life; comparative example 10 does not perform annealing softening treatment, the work hardening continues to accumulate, the material brittleness increases, the plasticity decreases sharply, and the material is easily broken due to stress concentration during fatigue; comparative example 11 does not perform phosphating treatment, lacks a lubricating layer during drawing, and surface scratches are generated, which increases the resistivity and makes the surface defects become fatigue crack sources, shortening the service life; comparative example 12 has a single pass deformation of more than 20% of the critical value, the internal plastic deformation limit of the wire is exceeded, micro-cracks are generated, the structure integrity is destroyed, and finally the plasticity and fatigue resistance are greatly deteriorated.

[0131] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art, according to the technical solution and inventive concept of the present application, makes equivalent replacement or change within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for forming a gold-silver-copper-manganese alloy wire, characterized in that, Includes the following steps Step (1): Batching and smelting; Weigh out the following 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. In a vacuum environment, first add the gold, silver, and copper to the melting furnace in proportion and melt them. Keep the melt temperature above 1200℃ and add manganese. Finally, add the silver-yttrium alloy and stir for 30-120 seconds to obtain a uniform alloy melt. 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 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. Step (3): Homogenization process; After removing risers, shrinkage cavities, and gating defects 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. Step (4): Hot rolling forming; The ingot that has been homogenized in 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%~80%, the rolling passes are 2-4, and after rolling into bars, the bars are air-cooled and pickled to obtain bars. The rolling speed is 0.1-1 m / s, and it needs to be rolled 3-4 times. After rolling 2-3 times, annealing is performed at a temperature of 200℃-400℃ for 1-3 hours. The protective atmosphere is vacuum, and it is cooled in the furnace. Step (5): Cold drawing forming; After surface pretreatment, the rolled bar from step (4) is placed in a die for cold drawing: The initial cold drawing deformation is controlled at 5%-8%, and the deformation is gradually increased in subsequent cold drawing passes. The deformation in a single pass is ≤20%, and the drawing speed is 0.5-2m / s. When the cumulative cold drawing deformation exceeds 50%, annealing and softening treatment is required. When the material reaches a diameter close to the target diameter, the final 1-2 cold drawing passes are performed, at which point the deformation is controlled at 3%~10%, and the alloy wire of the required size is finally obtained. The surface pretreatment of the bar is phosphating. 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 bar is washed with water, dried, and finally coated with a lubricant to complete the surface pretreatment of the bar. Step (6): Post-processing; Stress-relief annealing is completed at 300-500℃ for 1-2 hours under a nitrogen protective atmosphere. After stress-relief annealing, the wire surface is cleaned and electrolytically polished to obtain a gold-silver-copper-manganese alloy wire.

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

3. The method for forming gold-silver-copper-manganese alloy wire according to claim 1, characterized in that, In step (2), the casting temperature of the alloy melt is 1150℃-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℃.

4. The method for forming gold-silver-copper-manganese alloy wire according to claim 1, characterized in that, In step (3), the homogenization process takes 2-12 hours.

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

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

7. The method for forming gold-silver-copper-manganese alloy wire according to claim 1, characterized in that, In step (6), the electrolyte in the electropolishing process is a phosphoric acid aqueous solution with a mass fraction of 60-80% and glycerol with a mass fraction of 2g / L. The electropolishing temperature is 40℃-60℃, the voltage is 5-10V, and the time is 20-60s.

8. A gold-silver-copper-manganese alloy wire prepared by a forming method for gold-silver-copper-manganese alloy wire as described in any one of claims 1-7.