A copper-nickel-tin-phosphorus alloy foil with low roughness and its preparation method

Abstract

The present invention discloses a low-roughness copper-nickel-tin-phosphorus alloy foil and a preparation method thereof. The preparation method includes horizontal continuous casting, double surface milling, cold blooming, heat treatment, pre-finishing rolling, continuous heat treatment and stress relief annealing. The low-roughness copper-nickel-tin-phosphorus alloy foil comprises raw materials with the following weight percentages: nickel 0.5 - 1.5%, tin 0.5 - 2.5%, phosphorus 0.05 - 0.015%, and the balance being copper and impurities, with the impurity content being less than 0.02%. By optimizing the feeding sequence, melting temperature, holding time, casting speed and cooling conditions, the present invention greatly reduces the component segregation of the solidification structure of the material. By controlling the deformation amount of each processing pass and the annealing process, the residual stress distribution of the alloy material is improved, and the processing flatness is effectively controlled. By the coordinated control of the processing deformation amount, aging temperature and time treatment process, the high-temperature softening resistance of the alloy material is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of copper alloy foil processing, and particularly relates to a low-roughness copper-nickel-tin-phosphorus alloy foil and a preparation method thereof. Background Art

[0002] For the research and industrialization project of high-performance Cu-Ni-Sn-P alloy thin strip for high-end connectors, currently in the domestic market, it is mainly imported from Japan's CAC5 (C19040). In China, it is in the R & D stage and has not yet formed a stable batch supply. The product is mainly applied to high-end connectors such as lead frames and LED light strips, and at the same time has important strategic significance for the technological upgrading of high-end connectors in China's aerospace, electronic information, new energy vehicles, etc.

[0003] Cu-Ni-Sn-P (C19040) alloy has many advantages such as high strength, high hardness, high elasticity, strong resistance to thermal stress relaxation, stable conductivity, weldability, plating ability, and non-toxic environmental protection, and is widely used in manufacturing large lead frame materials and connector materials for electronic appliances, etc. In recent years, the wave of the information revolution represented by the information superhighway has been promoting the rapid development of the world's electronic information industry, which has become a strategic industry driving world economic growth. China's electronic information industry is also developing rapidly with unprecedented opportunities and has become a pillar industry of the country. Integrated circuits, semiconductor discrete devices, and new components are important foundations of the electronic information industry. The performance and quality of the lead frames and copper-based alloy strips for connectors used in these basic products will directly affect the functions and quality of the assembled products. Therefore, while vigorously developing electronic information products, it is necessary to correspondingly develop high-quality lead frames and copper-based alloy strips for connectors, which are basic materials and their supporting materials. At the same time, the 5G era has requirements of "low latency, low power consumption", requiring connector materials to have better transmission efficiency and conform to the development trend of "miniaturization, high current, high temperature rise" of electronic connectors.

[0004] The structure in the melting process of Cu-Ni-Sn-P alloy is prone to cause composition segregation, reducing the plasticity of the material, and has problems such as poor rolling process flatness and poor high-temperature softening resistance, seriously hindering the R & D and utilization of this alloy. Summary of the Invention

[0005] Aiming at the problems of composition segregation, poor flatness, and poor high-temperature softening resistance in the melting process of Cu-Ni-Sn-P alloy in the prior art, the present invention provides a low-roughness copper-nickel-tin-phosphorus alloy foil and a preparation method thereof. The copper-nickel-tin-phosphorus alloy prepared by this method has a thin thickness, low roughness, good flatness, and good high-temperature softening resistance.

[0006] The present invention is achieved through the following technical solutions:

[0007] A preparation method of a low-roughness copper-nickel-tin-phosphorus alloy foil, comprising the following steps:

[0008] (1) Horizontal continuous casting: Melting and casting are carried out according to the alloy chemical composition. The melting temperature is 1220 - 1250 °C, the casting temperature is 1160 - 1180 °C, the reverse pushing distance before pulling is 1.0 - 1.3 mm, the reverse pushing speed is 6 - 10 mm / s, the forward pulling distance is 8 - 15 mm, the forward pulling speed is 5 - 10 mm / s, and the pause time is 2 - 5 s to process into a coiled blank;

[0009] The alloy chemical composition includes raw materials with the following weight percentages: nickel 0.5 - 1.5%, tin 0.5 - 2.5%, phosphorus 0.05 - 0.15%, and the balance is copper and impurities, and the impurity content is less than 0.02%;

[0010] (2) Double milling: Use a carbide milling cutter, the single-sided milling amount is 0.5 - 1.0 mm, milling is carried out 2 - 3 times, the milling cutter rotation speed is 700 - 900 r / min, and the milling speed is 3 - 8 m / min;

[0011] (3) Cold blooming: Process through 7 - 10 passes to a thickness of 0.6 - 1.2 mm, the emulsion cooling amount is 0.2 - 0.6 bar, and the rolling speed is 100 - 160 m / min;

[0012] (4) Heat treatment: The temperature is 550 - 600 °C, the holding time is 2 - 10 h, and it is taken out of the furnace after cooling to room temperature;

[0013] (5) Pre-finishing rolling: Process through 4 - 7 passes to 0.19 - 0.5 mm, the rolling oil cooling amount is 6 - 8 bar, the rolling speed is 200 - 300 m / min, and the roll roughness is 0.07 - 0.15 μm;

[0014] (6) Continuous heat treatment: The annealing temperature is 750 - 800 °C, the speed is 30 - 50 m / min, and the alloy grain size after annealing is 10 - 20 μm;

[0015] (7) Finishing rolling: The total processing rate is controlled at 15 - 25%, rolled to 0.05 - 0.12 mm, the rolling oil cooling amount is 6 - 8 bar, the rolling speed is 200 - 300 m / min, and the roll roughness is 0.06 - 0.08 μm;

[0016] (8) Stress relief annealing: The temperature is 200 - 350 °C, and the annealing speed is 20 - 50 mm / min.

[0017] Further, the heat treatment in step (4) uses a bell-type heating furnace; the continuous heat treatment in step (6) and the stress relief annealing in step (8) use a continuous air-cushion heating furnace.

[0018] Further, the specific steps of step (1) smelting and casting are as follows: First, add cathode copper and nickel plates. After the smelting is completed and the temperature reaches 1220 - 1250 °C, expose the molten copper on the surface for 5 - 10 min, cover it with charcoal with a thickness of 200 - 400 mm, and keep it for 20 - 30 min. Then add tin ingots and phosphorus copper alloy, and continue smelting for 20 - 30 min.

[0019] Further, the thickness of the coiled blank in step (1) is 10 - 15 mm.

[0020] Further, the total cold rolling reduction rate in step (3) is 85 - 95%, and the single - pass reduction rate is 20 - 30%.

[0021] Further, the total pre - finishing reduction rate in step (5) is 50 - 80%, and the single - pass reduction rate is 15 - 25%.

[0022] Further, the number of finishing passes in step (7) is 3 - 6 passes, and the total reduction rate is 25 - 60%.

[0023] In the present invention, the low - roughness copper - nickel - tin - phosphorus alloy foil prepared by the above - mentioned preparation method has a thickness of 0.05 - 0.12 mm.

[0024] Beneficial Effects

[0025] By optimizing the feeding sequence, smelting temperature, holding time, casting speed, and cooling conditions, the present invention greatly reduces the segregation of the solidification structure components of the material. By controlling the deformation amount of the processing passes and the annealing process, the residual stress distribution of the alloy material is improved, and the processing flatness is effectively controlled. Through the coordinated control of the processing deformation amount, aging temperature, and time treatment process, the high - temperature softening resistance of the alloy material is improved. Specific Embodiments

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. The described embodiments are only some of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] Example 1

[0028] The low - roughness copper - nickel - tin - phosphorus alloy foil is composed of the following elements by weight percentage: nickel 1.0%, tin 1.5%, phosphorus 0.05%, and the balance is copper and impurities, with the impurity content less than 0.02%;

[0029] The processing method of the low - roughness copper - nickel - tin - phosphorus alloy foil includes the following steps:

[0030] (1)Horizontal continuous casting: Melting and casting are carried out according to the alloy chemical composition; Melting conditions: First, add cathode copper and nickel plates. After melting is completed and the temperature reaches 1220 °C, expose the molten copper on the surface for 5 min, cover it with 200 mm thick charcoal, keep it for 20 min, then add tin ingots and phosphor copper alloy, continue melting for 20 - 30 min, analyze the content of each component, the casting temperature is 1160 °C, the reverse pushing distance before drawing is 1.0 mm, the reverse pushing speed is 6 mm / s, the forward drawing distance is 8 mm, the forward drawing speed is 5 mm / s, and the pause time is 2 s to process into a coiled blank, and the thickness of the coiled blank is 14 mm;

[0031] (2)Facing: Use a carbide milling cutter, face mill on both sides, mill 2 times, the milling amount is 0.6 mm, the milling cutter speed is 700 r / min, and the milling speed is 3 m / min;

[0032] (3)Cold blooming: The total processing rate is 94%, processed in 9 passes, the single - pass processing rate is 20 - 30% for processing, processed to a thickness of 0.8 mm, the cooling amount of the emulsion is 0.2 bar, and the rolling speed is 100 m / min;

[0033] (4)Heat treatment: The temperature is 550 °C, the holding time is 4 h, use a bell - type heating furnace, after holding is completed, cool to room temperature and then take out of the furnace;

[0034] (5)Pre - finishing rolling: The total processing rate is 76%, processed to 0.19 mm in 6 passes, the single - pass processing rate is 15 - 25%, the cooling amount of the rolling oil is 6 - 8 bar, the rolling speed is 200 m / min, and the roll roughness is 0.11 μm;

[0035] (6)Continuous heat treatment: Use a continuous air - cushion type heating furnace for annealing treatment, the annealing temperature is 750 °C, the speed is 30 m / min, and the alloy grain size after annealing is 10 μm;

[0036] (7)Finishing rolling: Rolled to 0.11 mm in three passes, the cooling amount of the rolling oil is 6 bar, the rolling speed is 200 m / min, and the roll roughness is 0.07 μm;

[0037] (8)Stress - relieving annealing: Use a continuous air - cushion type heating furnace for annealing treatment, the temperature is 210 °C, and the annealing speed is 22 mm / min.

[0038] Example 2

[0039] The low - roughness copper - nickel - tin - phosphorus alloy foil consists of the following elements by weight percentage: nickel 1.2%, tin 2.0%, phosphorus 0.1%, and the balance is copper and impurities, and the impurity content is less than 0.02%; The processing method of the low - roughness copper - nickel - tin - phosphorus alloy foil includes the following steps:

[0040] (1)Horizontal continuous casting: Melting and casting are carried out according to the alloy chemical composition; Melting conditions: First, add cathode copper and nickel plates. After melting is completed and the temperature reaches 1235 °C, expose the molten copper on the surface for 6.5 min, cover it with 300 mm thick charcoal, keep it for 25 min, then add tin ingots and phosphorus copper alloy, continue melting for 20 - 30 min, analyze the content of each component, the casting temperature is 1170 °C, the reverse push distance before drawing is 1.2 mm, the reverse push speed is 8 mm / s, the forward draw distance is 12 mm, the forward draw speed is 8 mm / s, the pause time is 3 s, and it is processed into a coiled blank with a thickness of 13 mm;

[0041] (2)Facing: Use a carbide milling cutter, double-sided milling, milling 2 times, the milling amount is 0.7 mm, the milling cutter speed is 800 r / min, and the milling speed is 5 m / min;

[0042] (3)Cold blooming: Process through a total processing rate of 94%, in 9 passes, with a single-pass processing rate of 20 - 30% to a thickness of 0.74 mm, the emulsion coolant flow rate is 0.4 bar, and the rolling speed is 140 m / min;

[0043] (4)Heat treatment: The temperature is 560 °C, the holding time is 6 h, use a bell-type heating furnace, after holding, cool to room temperature and then take out of the furnace;

[0044] (5)Pre-finishing rolling: Process through a total processing rate of 78.7%, in 7 passes to 0.16 mm, with a single-pass processing rate of 15 - 25%, the rolling oil coolant flow rate is 6 - 8 bar, the rolling speed is 250 m / min, and the roll roughness is 0.1 μm

[0045] (6)Continuous heat treatment: Carry out annealing treatment using a continuous air-cushion heating furnace, the annealing temperature is 780 °C, the speed is 40 m / min, and the alloy grain size after annealing is 15 μm;

[0046] (7)Finishing rolling: Roll to 0.08 mm in four passes, the rolling oil coolant flow rate is 7 bar, the rolling speed is 250 m / min, and the roll roughness is 0.06 μm;

[0047] (8)Stress relief annealing: Carry out annealing treatment using a continuous air-cushion heating furnace, the temperature is 250 °C, and the annealing speed is 30 mm / min.

[0048] Example 3

[0049] The low-roughness copper-nickel-tin-phosphorus alloy foil consists of the following elements by weight percentage: nickel 1.5%, tin 2.5%, phosphorus 0.15%, and the balance is copper and impurities, with the impurity content less than 0.02%;

[0050] The processing method of the low-roughness copper-nickel-tin-phosphorus alloy foil includes the following steps:

[0051] (1)Horizontal continuous casting: Melting and casting are carried out according to the alloy chemical composition; Melting conditions: First, add cathode copper and nickel plates. After melting is completed and the temperature reaches 1250 °C, expose the molten copper on the surface for 10 min, cover it with 400 mm thick charcoal, keep it for 30 min, then add tin ingots and phosphor copper alloy, continue melting for 20 - 30 min, analyze the content of each component, the casting temperature is 1180 °C, the reverse push distance before pulling is 1.3 mm, the reverse push speed is 10 mm / s, the forward pull distance is 15 mm, the forward pull speed is 10 mm / s, the pause time is 5 s to process into a coiled blank, and the thickness of the coiled blank is 12 mm;

[0052] (2)Facing: Use a carbide milling cutter, face mill on both sides, mill 3 times, the milling amount is 0.8 mm, the milling cutter speed is 900 r / min, and the milling speed is 8 m / min;

[0053] (3)Cold blooming: Through a total processing rate of 94.6%, it is processed in 10 passes, with a single-pass processing rate of 20 - 30% for processing until the thickness reaches 0.6 mm, the cooling amount of the emulsion is 0.6 bar, and the rolling speed is 160 m / min;

[0054] (4)Heat treatment: The temperature is 580 °C, the holding time is 6 h, use a bell-type heating furnace, after the holding is completed, cool it to room temperature and then take it out of the furnace;

[0055] (5)Pre-finishing rolling: Through a total processing rate of 80%, it is processed in 6 passes to 0.12 mm, the single-pass processing rate is 15 - 25%, the cooling amount of the rolling oil is 8 bar, the rolling speed is 300 m / min, and the roll roughness is 0.1 μm

[0056] (6)Continuous heat treatment: Use a continuous air-cushion heating furnace for annealing treatment, the annealing temperature is 800 °C, the speed is 50 m / min, and the alloy grain size after annealing is 20 μm;

[0057] (7)Finishing rolling: Roll to 0.05 mm in 5 passes, the cooling amount of the rolling oil is 8 bar, the rolling speed is 300 m / min, and the roll roughness is 0.06 μm;

[0058] (8)Stress relief annealing: Use a continuous air-cushion heating furnace for annealing treatment, the temperature is 350 °C, and the annealing speed is 50 mm / min.

[0059] Comparative example 1: The alloy composition is adjusted to nickel 1.5%, tin 2.5%, phosphorus 0.15%, and the balance is copper and impurities, with the impurity content less than 0.02%; The other steps are the same as those in Example 1.

[0060] Comparative example 2: Adjust the annealing temperature of the continuous air-cushion heating furnace in step (6) to 730 °C, the speed to 20 m / min, and the alloy grain size after annealing to 25 μm; The other steps are the same as those in Example 1.

[0061] Analyze the properties of the copper-nickel-tin-phosphorus alloy foils prepared in Examples 1 to 3 and Comparative Examples 1 to 2, including tensile strength, hardness, conductivity, roughness, and high-temperature softening temperature. The results are shown in Table 1 below:

[0062] Table 1 Performance Analysis of Low-Roughness Copper-Nickel-Tin-Phosphorus Alloy Foils

[0063] 。

Claims

1. A preparation method of a copper-nickel-tin-phosphorus alloy foil with low roughness, characterized in that, it includes the following steps: (1) Horizontal continuous casting: Melting and casting are carried out according to the alloy chemical composition. The melting temperature is 1220 - 1250 °C, the casting temperature is 1160 - 1180 °C, the reverse pushing distance before pulling is 1.0 - 1.3 mm, the reverse pushing speed is 6 - 10 mm / s, the forward pulling distance is 8 - 15 mm, the forward pulling speed is 5 - 10 mm / s, and the pause time is 2 - 5 s to process into a coiled blank; The alloy chemical composition includes raw materials with the following weight percentages: nickel 1.0 - 1.2%, tin 1.5 - 2.0%, phosphorus 0.05 - 0.015%, and the balance is copper and impurities, and the impurity content is less than 0.02%; (2) Double face milling: Use a carbide milling cutter, the single side milling amount is 0.5 - 1.0 mm, milling is carried out 2 - 3 times, the milling cutter rotation speed is 700 - 900 r / min, and the milling speed is 3 - 8 m / min; (3) Cold blooming: Process through 7 - 10 passes to a thickness of 0.6 - 1.2 mm, the emulsion cooling amount is 0.2 - 0.6 bar, and the rolling speed is 100 - 160 m / min; (4) Heat treatment: The temperature is 550 - 600 °C, the holding time is 2 - 10 h, and it is taken out of the furnace after cooling to room temperature; (5) Pre-finishing rolling: Process through 4 - 7 passes to 0.19 - 0.5 mm, the rolling oil cooling amount is 6 - 8 bar, the rolling speed is 200 - 300 m / min, and the roll roughness is 0.07 - 0.15 μm; (6) Continuous heat treatment: The annealing temperature is 750 - 800 °C, the speed is 30 - 50 m / min, and the alloy grain size after annealing is 10 - 20 μm; (7) Finishing rolling: The total processing rate is 25 - 60%, rolled to 0.05 - 0.12 mm, the rolling oil cooling amount is 6 - 8 bar, the rolling speed is 200 - 300 m / min, and the roll roughness is 0.06 - 0.08 μm; (8) Stress relief annealing: The temperature is 200 - 350 °C, and the annealing speed is 20 - 50 mm / min.

2. The preparation method of the copper-nickel-tin-phosphorus alloy foil with low roughness according to claim 1, characterized in that, the heat treatment in step (4) uses a bell-type heating furnace; the continuous heat treatment in step (6) and the stress relief annealing in step (8) use a continuous air-cushion heating furnace.

3. The preparation method of the copper-nickel-tin-phosphorus alloy foil with low roughness according to claim 1, characterized in that, the specific steps of melting and casting in step (1) are: First add cathode copper and nickel plates. After the melting is completed and the temperature reaches 1220 - 1250 °C, expose the molten copper on the surface for 5 - 10 min, cover with charcoal with a thickness of 200 - 400 mm, keep it for 20 - 30 min, and then add tin ingots and phosphorus copper alloy, and continue melting for 20 - 30 min.

4. The preparation method of the copper-nickel-tin-phosphorus alloy foil with low roughness according to claim 1, characterized in that, the thickness of the coiled blank described in step (1) is 10 - 15 mm.

5. The preparation method of the copper-nickel-tin-phosphorus alloy foil with low roughness according to claim 1, characterized in that, The total cold blanking processing rate described in step (3) is 85-95%, and the single-pass processing rate is 20-30%.

6. The method for preparing a low-roughness copper-nickel-tin-phosphorus alloy foil according to claim 1, wherein, the total processing rate of pre-finishing rolling in step (5) is 50-80%, and the single-pass processing rate is 15-25%.

7. The method for preparing a low-roughness copper-nickel-tin-phosphorus alloy foil according to claim 1, wherein, the number of finishing rolling passes in step (7) is 3-6 passes.

8. A low-roughness copper-nickel-tin-phosphorus alloy foil prepared by the preparation method according to any one of claims 1-7, wherein, the thickness is 0.05-0.12 mm.