Copper wire for tin / silver plating and preparation method and application thereof

Abstract

The invention belongs to the technical field of nonferrous metal material processing, and particularly relates to a preparation method of a tin / silver plated copper wire rod, which comprises the following steps: (1) preparing a copper casting rod by adopting an up-drawing continuous casting technology at a traction rate of 0.5-0.8 m / min; (2) continuously extruding the copper casting rod obtained in the step (1) to obtain a copper extrusion rod with a required diameter; (3) the copper extrusion rod obtained in the step (2) is subjected to continuous drawing annealing, and an annealed soft copper wire with the ductility higher than 20% and the resistivity lower than 0.0170 omega.mm < 2 > / m is obtained; and (4) the annealed soft copper wire obtained in the step (3) is subjected to surface treatment, and the copper wire with the yield strength being 150-320 MPa and the tensile strength being 420-560 MPa is obtained. The method is simple in process, high in production efficiency, low in cost and easy to realize industrial production; the prepared copper wire is accurate and controllable in oxygen content, high in conductivity and high in tensile strength and yield strength.

Description

Technical Field

[0001] The invention belongs to the technical field of nonferrous metal material processing, and in particular relates to a copper wire for tin / silver plating and a preparation method and application thereof. Background Art

[0002] The aerospace industry is an important part of the modern industrial field. With the advancement of science and technology and people's increasing demand for exploring the universe, the aerospace industry has broad development prospects.

[0003] The photovoltaic industry has great development potential. As an important component of renewable energy, solar energy has many advantages and is the main trend of my country's future new energy development. It has broad long-term development space. Driven by solar photovoltaics, renewable energy power generation capacity will increase by 60% between 2020 and 2026, with total power generation reaching 4,800GW, of which solar photovoltaic power generation will account for 60% of the growth. And by 2026, renewable energy will account for 95% of the world's new power generation, and my country's renewable energy power generation will account for about 43% of the global total, continuing to maintain the largest application market.

[0004] my country has abundant solar energy resources, and the land area suitable for photovoltaic power generation and the area of ​​buildings receiving sunlight are large. With the continuous increase in global energy demand, the importance of solar photovoltaic power generation will become increasingly important. The future prospects of the solar photovoltaic industry are very broad, and solar photovoltaic power generation will become one of the important sources of energy in the future.

[0005] More and more terminal tin-plated and silver-plated products in aerospace, photovoltaics, etc. directly use oxygen-free medium-drawn copper wire as raw material. However, tin-plated and silver-plated base materials have high requirements on wire surface smoothness, and traditional process products can no longer meet market demand. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for preparing tin / silver-plated copper wire, which reduces the material input cost to the greatest extent while continuing the excellent performance of the traditional process, so that the prepared copper wire has high wire surface quality, high yield and tensile strength, and can meet the market demand for tin / silver-plated wires for high-end photovoltaics and aerospace.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows: A method for preparing a tin / silver-plated copper wire comprises the following steps: (1) The copper casting rod is prepared by upward continuous casting technology, and the pulling rate is 0.5-0.8 m / min; (2) continuously extruding the copper cast rod obtained in step (1) to obtain a copper extruded rod of a desired diameter; (3) The copper extruded rod obtained in step (2) is subjected to continuous drawing annealing to obtain a copper extruded rod having an elongation higher than 20% and a resistivity lower than 0.0170 Ω·mm. 2 / m annealed soft copper wire; (4) Surface treatment is performed on the annealed soft copper wire obtained in step (3) to obtain a tin / silver-plated copper wire having a yield strength of 150 to 320 MPa and a tensile strength of 420 to 560 MPa.

[0008] In a preferred example, in step (1), the raw material is a cathode copper plate, and the total copper content of the prepared copper cast rod is higher than 99.995wt.%, the oxygen content is lower than 5ppm, and the diameter is 12.5-16mm.

[0009] In a preferred example, in step (2), the extrusion die temperature is 400-750° C., the extrusion wheel speed is 5-12 r / min, and the diameter of the prepared copper extrusion rod is 8-10 mm.

[0010] In a preferred example, in step (3), the deformation amount of the drawing pass is 15-25%, the concentration of the drawing liquid is 7-8%, the drawing rate is 1000-1200 m / min, the annealing coefficient is 25-35%, and the diameter of the prepared annealed soft copper wire is 0.4-0.8 mm, the elongation is higher than 20%, and the resistivity is lower than 0.0170 Ω·mm 2 / m.

[0011] In a preferred example, in step (4), the surface is treated by using a mold, the deformation is 0.3-0.5%, and the mold passing rate is 1000-1200 m / min.

[0012] Based on a general inventive concept, another object of the present invention is to provide a tin / silver-plated copper wire prepared by the above-mentioned preparation method, wherein the total copper content of the tin / silver-plated copper wire is higher than 99.995wt.%, the oxygen content is lower than 5ppm, the elongation is higher than 20%, and the maximum resistivity at 20°C is lower than 0.0170Ω·mm 2 / m, yield strength is 150~320MPa, and tensile strength is 420~560MPa.

[0013] Another object of the present invention is to protect the application of the tin / silver-plated copper wire prepared by the preparation method in photovoltaic and aerospace materials.

[0014] The present invention uses high-purity electrolytic copper (cathode copper plate) as raw material, while continuing the excellent performance of traditional processes, it reduces the material input cost to the greatest extent; the up-drawing method is used for continuous casting production of copper rods, further controlling the processing cost within a reasonable range; and then the up-drawing casting rods are subjected to continuous extrusion and plastic deformation to obtain copper extruded rods, and combined with drawing, annealing and surface treatment processes, copper wires with high wire surface quality, high yield and tensile strength are obtained, which can meet the market demand for tin-plated / silver-plated wires for high-end photovoltaics and aerospace.

[0015] Compared with the prior art, the advantages and positive effects of the present invention are as follows: 1. The present invention adopts the method of upward continuous casting → continuous extrusion → continuous drawing → online annealing → surface treatment to produce copper wire, which has simple process, high production efficiency, low processing cost, and easy to realize industrial production; the oxygen content in the copper wire prepared by the process route of the present invention is precisely controllable.

[0016] 2. The copper wire obtained by the present invention has higher conductivity than the wire obtained by the dip coating process, and has higher tensile and yield strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The microstructure morphology and center magnified microstructure morphology of the copper cast rod in Example 1; Figure 2 This is a microstructure morphology diagram of the extruded copper rod in Example 1; Figure 3 This is a comparison chart of the wire surface of the annealed soft copper wire in Example 2 before and after the wire surface treatment by the mold. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in conjunction with specific embodiments, but the present invention is not limited to these embodiments. It should be noted that, under the premise of not conflicting, the embodiments described below or the technical features can be arbitrarily combined to form new embodiments. In the present invention, unless otherwise specified, all parts and percentages are mass units, and the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments, if not otherwise specified, are conventional methods in the art.

[0019] As used herein, the terms "comprises," "including," "contains," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0020] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range limited by a series of upper preferred values ​​and lower preferred values, this should be understood to specifically disclose all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including a range of "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this article, unless otherwise specified, this range is intended to include its end values ​​and all integers and fractions within this range.

[0021] Example 1

[0022] (1) The cathode copper plate is evenly put into the upward continuous casting melting furnace, the smelting temperature is 1200℃, the charcoal with a thickness of 220mm is covered on the liquid surface of the melting furnace, the temperature of the holding furnace is 1140℃, and the copper casting rod with a diameter of 16mm is pulled out by the upward continuous casting, and the pulling speed is 0.5m / min; Depend on Figure 1 It can be seen that the center of the copper casting rod is equiaxed crystal, surrounded by radial long strip grains, and there are holes in the center of the copper casting rod; (2) continuously extruding the copper cast rod, with a die diameter of 8 mm, to obtain an extruded copper rod that meets application requirements; Figure 2 It can be seen that after the continuous extrusion process, the copper rod grains are small and evenly distributed, and no defects such as holes and looseness are found.

[0023] The chemical composition and properties of the copper mother rod (copper cast rod) prepared in this embodiment are shown in Table 1 below.

[0024] Table 1 Chemical composition and properties of copper casting rod in Example 1

[0025] It can be seen from Table 1 that the resistivity of the copper cast rod prepared in this embodiment at 20°C is 0.016970Ω·mm 2 / m, which is much lower than the resistivity of oxygen-free copper rod in the national standard (less than 0.017241Ω·mm 2 / m) requirements.

[0026] Example 2

[0027] The extruded copper rod with a diameter of 8 mm obtained in Example 1 was continuously drawn to obtain an annealed soft copper wire with a diameter of 0.5 mm, and the annealing coefficient was 30%; the obtained annealed soft copper wire was processed by a mold to treat the wire surface (the comparison photos of the wire surface before and after the treatment are shown in FIG. Figure 3As shown in the figure, the deformation is 0.4%, and a copper wire with high surface quality and high yield strength is obtained; after measurement, the yield strength of the obtained copper wire is 312MPa, the tensile strength is 549MPa, the elongation is 22%, and the resistivity at 20℃ is 0.0170Ω·mm 2 / m.

[0028] The above embodiments are merely preferred implementations of the present invention. Any simple modification, amendment and substitution of the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a tin / silver-plated copper wire, characterized in that: The following steps are involved: (1) The copper casting rod is prepared by upward continuous casting technology, and the pulling rate is 0.5-0.8 m / min; (2) continuously extruding the copper cast rod obtained in step (1) to obtain a copper extruded rod of a desired diameter; (3) The copper extruded rod obtained in step (2) is subjected to continuous drawing annealing to obtain a copper extruded rod having an elongation higher than 20% and a resistivity lower than 0.0170 Ω·mm. 2 / m annealed soft copper wire; (4) Surface treatment is performed on the annealed soft copper wire obtained in step (3) to obtain a tin / silver-plated copper wire having a yield strength of 150 to 320 MPa and a tensile strength of 420 to 560 MPa.

2. The method for preparing a tin / silver-plated copper wire according to claim 1, characterized in that: In step (1), the raw material is a cathode copper plate, and the total copper content of the prepared copper cast rod is higher than 99.995wt.%, the oxygen content is lower than 5ppm, and the diameter is 12.5-16mm.

3. The method for preparing a tin / silver-plated copper wire according to claim 1, characterized in that: In step (2), the extrusion die temperature is 400-750° C., the extrusion wheel speed is 5-12 r / min, and the diameter of the prepared copper extrusion rod is 8-10 mm.

4. The method for preparing a tin / silver-plated copper wire according to claim 1, characterized in that: In step (3), the deformation amount of the drawing pass is 15-25%, the concentration of the drawing liquid is 7-8%, the drawing rate is 1000-1200 m / min, the annealing coefficient is 25-35%, and the diameter of the prepared annealed soft copper wire is 0.4-0.8 mm, the elongation is higher than 20%, and the resistivity is lower than 0.0170 Ω·mm 2 / m.

5. The method for preparing a tin / silver-plated copper wire according to claim 1, characterized in that: Step (4), the surface is treated by using a mold, the deformation is 0.3-0.5%, and the mold passing rate is 1000-1200 m / min.

6. A tin / silver-plated copper wire prepared by the preparation method according to any one of claims 1 to 5, wherein the total copper content of the tin / silver-plated copper wire is higher than 99.995wt.%, the oxygen content is lower than 5ppm, the elongation is higher than 20%, and the maximum resistivity at 20°C is lower than 0.0170Ω·mm 2 / m, yield strength is 150~320MPa, and tensile strength is 420~560MPa.

7. Use of a tin / silver-plated copper wire prepared by the preparation method according to any one of claims 1 to 5 in photovoltaic and aerospace materials.

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