A Cu-Ni-P alloy strip, its manufacturing method and application

Abstract

This invention discloses a Cu-Ni-P alloy strip, its manufacturing method, and its applications, relating to the field of copper alloy technology. The invention provides a manufacturing method for Cu-Ni-P alloy strip, comprising the following steps: continuous casting → homogenization heat treatment → continuous extrusion of slab → primary cold rolling → double-stage aging heat treatment → secondary cold rolling. The manufacturing method provided by this invention has a short process and low cost. The Cu-Ni-P alloy strip provided by this invention possesses excellent strength, electrical conductivity, and bending properties.

Description

Technical Field

[0001] This invention relates to the field of copper alloy technology, and in particular to a Cu-Ni-P alloy strip, its manufacturing method, and its application. Background Technology

[0002] Copper alloys are widely used in electrical transmission systems across various industries due to their excellent electrical and mechanical properties. In recent years, the rapid development of industries such as integrated circuits, rail transportation, aerospace, and communications has placed higher demands on the electrical conductivity and strength of copper alloys. Currently, the development of high-strength, high-conductivity copper alloys mainly relies on precipitation strengthening. The precipitation of precipitates purifies the matrix, significantly improving electrical and thermal conductivity, while simultaneously enhancing alloy strength by hindering dislocation movement.

[0003] Commercially available high-strength, high-conductivity copper alloys are mainly Cu-Cr-Zr and Cu-Ni-Si alloys. Cu-Cr-Zr alloys have a tensile strength of approximately 500-580 MPa and a conductivity of approximately 75%-85%, exhibiting excellent conductivity but relatively low strength. Cu-Ni-Si alloys have a tensile strength of approximately 550-950 MPa and a conductivity of approximately 35%-55%, showing higher strength but poorer conductivity. Cu-Ni-P alloys, relying on the extremely low solid solubility of the Ni-P phase in the Cu matrix and the significant precipitation strengthening effect, achieve a tensile strength exceeding 600 MPa and a conductivity exceeding 60%, making them a high-strength, high-conductivity copper alloy with excellent performance and a promising market prospect in lead frames, connectors, and other fields. However, the production process of Cu-Ni-P alloys all adopts a process route of semi-continuous casting-walking furnace heating-hot rolling-milling-first cold rolling-air cushion furnace solution heat treatment-second cold rolling-aging heat treatment-third cold rolling. The process is long, the yield is low, and the production cost is high, which leads to its high price.

[0004] In response to a series of problems in the current copper alloy strip industry, there is an urgent need to develop a short-process, low-cost manufacturing method to produce Cu-Ni-P alloys with excellent strength and conductivity, so as to realize the widespread application of high-strength and high-conductivity copper alloys and promote the upgrading of various industries. Summary of the Invention

[0005] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a Cu-Ni-P alloy strip, its manufacturing method, and its applications. The manufacturing method provided by this invention has a short process and low cost, and the Cu-Ni-P alloy strip provided by this invention possesses both excellent strength and electrical conductivity.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for manufacturing Cu-Ni-P alloy strip, comprising the following steps: continuous casting → homogenization heat treatment → continuous extrusion slab → primary cold rolling → double-stage aging heat treatment → secondary cold rolling;

[0007] (1) Using copper alloy as raw material, copper alloy casting rods are prepared by upward continuous casting process; the copper alloy includes the following components in mass percentage: Ni: 0.3-1.3wt%, P: 0.05-0.3%, impurities ≤0.4%, copper: balance, and the mass percentage ratio of Ni to P is 3.0-5.5;

[0008] (2) The copper alloy casting rod is subjected to homogenization heat treatment and continuous extrusion to prepare extruded slabs;

[0009] (3) The extruded slab is subjected to a first cold rolling, a two-stage aging heat treatment, and a second cold rolling process to obtain the Cu-Ni-P alloy strip; the total deformation in the first cold rolling is 70-95%; in the two-stage aging process, the first aging temperature is 200-300℃ and the aging time is 3-6h, the second aging temperature is 300-500℃ and the aging time is 1-4h; the total deformation in the second cold rolling is 40-70%.

[0010] Compared to existing upward casting-continuous extrusion technology, this invention first performs homogenization heat treatment on the copper alloy casting rod prepared by the upward continuous casting process to eliminate grain boundary segregation and fully dissolve the Ni-P crystalline phase before proceeding with the subsequent continuous extrusion process. This invention limits the elemental content of the copper alloy raw material in the upward continuous casting process and further limits the mass percentage ratio of Ni and P. The elemental content of the copper alloy raw material has a significant impact on the final properties. When the Ni to P mass ratio is close to 4.74, the solid solubility of Ni and P elements decreases significantly. This provides favorable conditions for improving the strength and conductivity of the alloy through precipitation strengthening, but it also increases the difficulty of Ni and P solid solution. Without high-temperature homogenization treatment of the billet, it is difficult to completely dissolve the Ni-P crystalline phase during solidification using only short-term high-temperature solid solution during continuous extrusion. In this invention, a small amount of Ni-P phase precipitates during the homogenization heat treatment cooling process. However, because this precipitated phase is small in size and quantity, it can be dissolved back using short-term high-temperature heating during continuous extrusion, resulting in a high solid solubility microstructure.

[0011] This invention produces an extruded slab through continuous extrusion. The extruded slab contains a fine, dynamically recrystallized structure to provide a high grain boundary density. Simultaneously, a large deformation (70-95%) is applied during a single cold rolling process to obtain a high density of dislocations within the metal crystals, increasing precipitation kinetics. Furthermore, the aging annealing process of this invention employs a two-stage aging heat treatment: a first-stage low-temperature, long-time aging process to obtain high-density Ni-P clusters, and a second-stage high-temperature, short-time aging process to generate a large amount of precipitates. This significantly increases the density of Ni-P precipitates in the alloy after aging heat treatment, giving the alloy excellent strength and electrical conductivity.

[0012] Preferably, in step (1), the casting temperature in the upward continuous casting is 1160-1200℃, and the diameter of the casting rod is 25-30mm.

[0013] Preferably, in step (2), the heat treatment temperature in the homogenization heat treatment is 850-900℃ and the heat treatment time is 3-5h; the extrusion roller speed in the continuous extrusion slab is 3-5r / min and the preheating temperature of the extrusion die is 450-650℃.

[0014] Preferably, in step (2), the thickness of the extruded slab obtained after continuous extrusion is 12-14 mm.

[0015] The present invention produces thinner continuously extruded slabs, which are immediately water-quenched after being extruded from the cavity. The amount of elements desorbed during the water quenching cooling process is far less than that in the traditional hot rolling process. Subsequent aging heat treatment can be carried out without solution treatment in an air cushion furnace, which shortens the process flow and reduces production costs.

[0016] Preferably, in step (3), the thickness of the Cu-Ni-P alloy strip obtained after sequentially performing one cold rolling, two-stage aging heat treatment, and two cold rolling processes is 0.2-1.5 mm.

[0017] Furthermore, the present invention also provides Cu-Ni-P alloy strips manufactured by the manufacturing method of the aforementioned Cu-Ni-P alloy strips.

[0018] In addition, the present invention also provides the application of the Cu-Ni-P alloy strip in the fields of integrated circuits, rail transportation, aerospace, and communications.

[0019] Preferably, the present invention provides the application of the Cu-Ni-P alloy strip in lead frames, automotive connectors, and ultrathin heat sinks.

[0020] Compared to existing technologies, the advantages of this invention are as follows: Compared to existing upward casting-continuous extrusion technology, this invention first performs homogenization heat treatment on the copper alloy casting rod prepared by the upward continuous casting process to eliminate grain boundary segregation and fully dissolve the Ni-P crystalline phase before proceeding with the subsequent continuous extrusion process. This invention limits the elemental content of the copper alloy raw material in the upward continuous casting process and further limits the mass percentage ratio of Ni and P. The inventors discovered in actual experiments that the elemental content of the copper alloy raw material has a significant impact on the final performance. When the mass ratio of Ni to P is close to 4.74, it significantly reduces the solid solubility of Ni and P, increasing the difficulty of Ni and P solid dissolution. Without high-temperature homogenization treatment of the casting billet, relying solely on short-term high-temperature solid dissolution during continuous extrusion is insufficient to completely dissolve the Ni-P crystalline phase during solidification. During the homogenization heat treatment cooling process of this invention, a small amount of Ni-P phase precipitates. However, due to the small size and quantity of this precipitated phase, short-term high-temperature heating during continuous extrusion can achieve the re-dissolution of the precipitated phase, resulting in a high solid solubility microstructure.

[0021] This invention produces an extruded slab through continuous extrusion. The extruded slab contains a fine, dynamically recrystallized structure to provide a high grain boundary density. Simultaneously, a large deformation (70-95%) is applied during a single cold rolling process to obtain a high density of dislocations within the metal crystals, increasing precipitation kinetics. Furthermore, the aging annealing process of this invention employs a two-stage aging heat treatment: a first-stage low-temperature, long-time aging process to obtain high-density Ni-P clusters, and a second-stage high-temperature, short-time aging process to generate a large amount of precipitates. This significantly increases the density of Ni-P precipitates in the alloy after aging heat treatment, giving the alloy excellent strength and electrical conductivity. Attached Figure Description

[0022] Figure 1 The images show the microstructure of the Cu-Ni-P alloy strip; where (a) is the microstructure of the Cu-Ni-P alloy strip prepared in Comparative Example 3, and (b) is the microstructure of the Cu-Ni-P alloy strip prepared in Example 1.

[0023] Figure 2 The images are TEM images of Cu-Ni-P alloy strips; where (a) is a TEM image of the Cu-Ni-P alloy strip prepared in Comparative Example 7, and (b) is a TEM image of the Cu-Ni-P alloy strip prepared in Example 1. Detailed Implementation

[0024] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The purpose is to provide a detailed understanding of the invention, not to limit it. All other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. Unless otherwise specified, the experimental reagents and instruments designed in the embodiments and comparative examples of this invention are commonly used reagents and instruments, all of which are commercially available. Unless otherwise specified, the experimental methods used in the embodiments and comparative examples are conventional methods; and unless otherwise specified, the raw materials used in parallel experiments are from the same batch.

[0025] The copper alloy used in this invention is made by mixing electrolytic copper with pure Ni and copper-phosphorus master alloy. The electrolytic copper comes from Jiangxi Copper Corporation Limited, the pure Ni comes from Tianjin Hejifeng Metal Materials Co., Ltd., and the copper-phosphorus master alloy comes from Suzhou Antibot Metal Products Co., Ltd.

[0026] A method for manufacturing Cu-Ni-P alloy strip includes the following steps: continuous casting → homogenization heat treatment → continuous extrusion slab → primary cold rolling → double-stage aging heat treatment → secondary cold rolling.

[0027] (1) A copper alloy casting rod is prepared using a copper alloy as raw material and an upward continuous casting process; the copper alloy comprises the following components in terms of mass percentage: Ni: 0.3-1.3wt%, P: 0.05-0.3%, impurities ≤0.4%, copper: balance, and the mass percentage ratio of Ni to P is 3.0-5.5; the casting temperature in the upward continuous casting is 1160-1200℃, and the diameter of the casting rod is 25-30mm;

[0028] (2) The copper alloy casting rod is subjected to homogenization heat treatment and continuous extrusion to prepare an extruded slab; the heat treatment temperature in the homogenization heat treatment is 850-900℃, and the heat treatment time is 3-5h; the extrusion wheel speed in the continuous extrusion slab is 3-5r / min, and the preheating temperature of the extrusion die is 450-650℃; in step (2), the thickness of the extruded slab obtained after continuous extrusion is 12-14mm.

[0029] (3) The extruded slab is subjected to a first cold rolling, a two-stage aging heat treatment, and a second cold rolling process in sequence to obtain the Cu-Ni-P alloy strip; the total deformation in the first cold rolling is 70-95%; in the two-stage aging process, the first aging temperature is 200-300℃ and the aging time is 3-6h, and the second aging temperature is 300-500℃ and the aging time is 1-4h; the total deformation in the second cold rolling is 40-70%; the thickness of the Cu-Ni-P alloy strip obtained after the first cold rolling, two-stage aging heat treatment, and second cold rolling process in sequence is 0.2-1.5mm.

[0030] Example 1

[0031] A method for manufacturing Cu-Ni-P alloy strip includes the following steps: continuous casting → homogenization heat treatment → continuous extrusion slab → primary cold rolling → double-stage aging heat treatment → secondary cold rolling.

[0032] (1) A copper alloy casting rod is prepared by using copper alloy as raw material and employing an upward continuous casting process; the copper alloy comprises the following components by mass percentage: Ni: 0.9wt%, P: 0.2%, impurities ≤0.4%, copper: balance, and the mass percentage ratio of Ni to P is 4.5; the casting temperature in the upward continuous casting is 1180℃, and the diameter of the casting rod is 25mm;

[0033] (2) The copper alloy casting rod is subjected to homogenization heat treatment and continuous extrusion to prepare an extruded slab; the heat treatment temperature in the homogenization heat treatment is 860℃ and the heat treatment time is 4h; the extrusion roller speed in the continuous extrusion slab is 3.5r / min and the preheating temperature of the extrusion die is 500℃; in step (2), the thickness of the extruded slab obtained after continuous extrusion is 12.6mm;

[0034] (3) The extruded slab is subjected to a first cold rolling, a two-stage aging heat treatment, and a second cold rolling process in sequence to obtain the Cu-Ni-P alloy strip; the total deformation in the first cold rolling is 85%; in the two-stage aging process, the first aging temperature is 280℃ and the aging time is 3h, the second aging temperature is 400℃ and the aging time is 1.5h; the total deformation in the second cold rolling is 60%.

[0035] Example 2

[0036] Compared with Example 1, only the raw materials in step (1) are different. The copper alloy raw materials used include the following components in terms of mass percentage: Ni: 1.3wt%, P: 0.25%, impurities ≤0.4%, copper: balance. The mass percentage ratio of Ni to P is 5.2. The other components, dosages and preparation methods are exactly the same.

[0037] Example 3

[0038] Compared with Example 1, only the raw materials in step (1) are different. The copper alloy raw materials used include the following components in terms of mass percentage: Ni: 0.55wt%, P: 0.15%, impurities ≤0.4%, copper: balance. The mass percentage ratio of Ni to P is 3.67. The other components, dosages and preparation methods are exactly the same.

[0039] Example 4

[0040] Compared with Example 1, only the heat treatment temperature and time in step (2) homogenization heat treatment are different. The heat treatment temperature is 900℃ and the heat treatment time is 3h. The other components, dosages and preparation methods are exactly the same.

[0041] Example 5

[0042] Compared with Example 1, only the extrusion wheel speed in step (2) is different, with the extrusion wheel speed being 5 r / min. The other components, dosages, and preparation methods are exactly the same.

[0043] Example 6

[0044] Compared with Example 1, only the preheating temperature of the extrusion die in step (2) is different. The preheating temperature of the extrusion die is 650°C. The other components, dosages and preparation methods are exactly the same.

[0045] Example 7

[0046] Compared with Example 1, only the total deformation in step (3) of the cold rolling is different. The total deformation in the cold rolling is 95%, while the other components, dosages and preparation methods are exactly the same.

[0047] Example 8

[0048] Compared with Example 1, only the total deformation in step (3) of the cold rolling is different. The total deformation in the cold rolling is 70%, while the other components, dosages and preparation methods are exactly the same.

[0049] Example 9

[0050] Compared with Example 1, only the selection of process parameters for the two-stage aging process in step (3) is different. The first-stage aging temperature is 220℃ and the aging time is 6h, while the second-stage aging temperature is 350℃ and the aging time is 4h. The other components, dosages and preparation methods are exactly the same.

[0051] Example 10

[0052] Compared with Example 1, only the total deformation in the second cold rolling in step (3) is different. The total deformation in the second cold rolling is 40%, while the other components, dosages and preparation methods are exactly the same.

[0053] Example 11

[0054] Compared with Example 1, only the total deformation in the second cold rolling in step (3) is different. The total deformation in the second cold rolling is 70%, while the other components, dosages and preparation methods are exactly the same.

[0055] Comparative Example 1

[0056] Compared with Example 1, only the raw materials in step (1) are different. The copper alloy raw materials used include the following components in terms of mass percentage: Ni: 0.9wt%, P: 0.45%, impurities ≤0.4%, copper: balance. The mass percentage ratio of Ni to P is 2. The other components, dosages and preparation methods are exactly the same.

[0057] Comparative Example 2

[0058] Compared with Example 1, only the raw materials in step (1) are different. The copper alloy raw materials used include the following components in terms of mass percentage: Ni: 1.2wt%, P: 0.15%, impurities ≤0.4%, copper: balance. The mass percentage ratio of Ni to P is 8. The other components, dosages and preparation methods are exactly the same.

[0059] Comparative Example 3

[0060] Compared to Example 1, only the homogenization heat treatment was omitted. Specifically, the preparation method is as follows:

[0061] A method for manufacturing Cu-Ni-P alloy strip includes the following steps: upward continuous casting → continuous extrusion of slab → primary cold rolling → double-stage aging heat treatment → secondary cold rolling;

[0062] (1) A copper alloy casting rod is prepared by using copper alloy as raw material and employing an upward continuous casting process; the copper alloy comprises the following components by mass percentage: Ni: 0.9wt%, P: 0.2%, impurities ≤0.4%, copper: balance, and the mass percentage ratio of Ni to P is 4.5; the casting temperature in the upward continuous casting is 1180℃, and the diameter of the casting rod is 25mm;

[0063] (2) The copper alloy casting rod is continuously extruded to prepare an extruded slab; the speed of the extrusion roller in the continuous extrusion slab is 3.5 r / min, and the preheating temperature of the extrusion die is 500℃; in step (2), the thickness of the extruded slab obtained after continuous extrusion is 12.6 mm.

[0064] (3) The extruded slab is subjected to a first cold rolling, a two-stage aging heat treatment, and a second cold rolling process in sequence to obtain the Cu-Ni-P alloy strip; the total deformation in the first cold rolling is 85%; in the two-stage aging process, the first aging temperature is 280℃ and the aging time is 3h, the second aging temperature is 400℃ and the aging time is 1.5h; the total deformation in the second cold rolling is 60%.

[0065] Comparative Example 4

[0066] Compared with Example 1, only the total deformation in step (3) of the cold rolling is different. The total deformation in the cold rolling is 50%, while the other components, dosages and preparation methods are exactly the same.

[0067] Comparative Example 5

[0068] Compared with Example 1, only the total deformation in the second cold rolling in step (3) is different. The total deformation in the second cold rolling is 20%, while the other components, dosages and preparation methods are exactly the same.

[0069] Comparative Example 6

[0070] Compared with Example 1, only the total deformation in the second cold rolling in step (3) is different. The total deformation in the second cold rolling is 80%, while the other components, dosages and preparation methods are exactly the same.

[0071] Comparative Example 7

[0072] Cu-Ni-P alloy strip was prepared using a traditional process: semi-continuous casting-hot rolling-milling-cold rolling-air cushion furnace annealing-small deformation rolling-single-stage aging-cold rolling. The raw materials were exactly the same as in Example 1. Specifically, the preparation method is as follows:

[0073] (1) Using copper alloy as raw material, a copper alloy billet is prepared by a semi-continuous casting process; the copper alloy includes the following components in terms of mass percentage: Ni: 0.9wt%, P: 0.2%, impurities ≤0.4%, copper: balance, and the mass percentage ratio of Ni to P is 4.5;

[0074] (2) The billet is hot rolled at an entry temperature of 900℃ and a final rolling temperature of 750℃. After milling, the hot-rolled billet is cold-rolled to a thickness of 0.8mm. The cold-rolled strip is sent to an air cushion furnace for annealing at a temperature of 800℃ and a running speed of 25m / min. After annealing, the strip is rolled to a thickness of 0.4mm and subjected to aging heat treatment at a temperature of 450℃ for 4 hours. After aging, the strip is rolled to a thickness of 0.2mm.

[0075] Performance testing

[0076] The Cu-Ni-P alloy strips prepared according to the embodiments and comparative examples of the present invention were subjected to relevant performance tests, as detailed below:

[0077] Tensile strength: Tested according to GB / T228.1-2021;

[0078] Vickers hardness: tested according to GB / T4320.1-2024;

[0079] Conductivity: Tested according to GB / T351-2019;

[0080] Bending performance: Tested according to GB / T15825.5, the rolling direction is defined as good way, and the transverse direction is defined as bad way.

[0081] The performance test results are shown in Table 1. In Examples 1-11 and Comparative Examples 1-6, thickness 1 represents the thickness of the extruded slab obtained after continuous extrusion. In Comparative Example 7, thickness 1 represents the thickness of the hot-rolled slab. Thickness 2 represents the thickness of the final Cu-Ni-P alloy strip.

[0082] Table 1

[0083]

[0084]

[0085] As shown in the table above, the manufacturing method of Cu-Ni-P alloy strip provided in this embodiment of the invention employs a process of upward continuous casting → homogenization heat treatment → continuous extrusion slab → single cold rolling → double-stage aging heat treatment → double cold rolling. The resulting alloy possesses both excellent strength and electrical conductivity, meeting current requirements for high strength and high conductivity alloys. The Cu-Ni-P alloy strip prepared by the manufacturing method provided in this embodiment of the invention simultaneously meets the requirements of a tensile strength of over 600 MPa and an electrical conductivity of over 60% IACS, satisfying current requirements for high strength and high conductivity alloys.

[0086] As can be seen from the comparison of Example 1 and Comparative Examples 1-2, when the mass percentage ratio of Ni to P in the copper alloy raw material is 3.0-5.5, the requirements of high strength and high conductivity can be met simultaneously. When the mass percentage ratio of Ni to P is too small or too large, the tensile strength and conductivity will decrease significantly.

[0087] As can be seen from the comparison between Example 1 and Comparative Example 3, the copper alloy rods prepared by the upward continuous casting process undergo homogenization heat treatment to eliminate grain boundary segregation and fully dissolve the Ni-P crystalline phases before subsequent continuous extrusion, which can improve the tensile strength and electrical conductivity of the alloy strip. Comparative Example 3, without homogenization heat treatment, suffers a significant decrease in tensile strength and electrical conductivity, failing to simultaneously meet the requirements of high strength and high conductivity. Figure 1The images show the microstructure of the Cu-Ni-P alloy strip; where (a) is the microstructure of the Cu-Ni-P alloy strip prepared in Comparative Example 3, and (b) is the microstructure of the Cu-Ni-P alloy strip prepared in Example 1.

[0088] As can be seen from the comparison of Example 1 and Comparative Examples 4-6, the different deformation amounts during cold rolling will lead to a decrease in the tensile strength or conductivity of the final alloy strip, and it will not be able to meet the requirements of high strength and high conductivity at the same time.

[0089] Comparative Example 7 is a traditional process. Compared with the traditional process, this application greatly simplifies the process flow, shortens the process steps, and reduces production costs. Figure 2 The images are TEM images of Cu-Ni-P alloy strips; where (a) is a TEM image of the Cu-Ni-P alloy strip prepared in Comparative Example 7, and (b) is a TEM image of the Cu-Ni-P alloy strip prepared in Example 1.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for manufacturing Cu-Ni-P alloy strip, characterized in that, Includes the following steps: Upward continuous casting → homogenization heat treatment → continuous extrusion slab → primary cold rolling → double-stage aging heat treatment → secondary cold rolling; (1) Using copper alloy as raw material, copper alloy casting rods are prepared by upward continuous casting process; the copper alloy includes the following components in mass percentage: Ni: 0.3-1.3wt%, P: 0.05-0.3%, impurities ≤0.4%, copper: balance, and the mass percentage ratio of Ni to P is 3.0-5.5; (2) The copper alloy casting rod is subjected to homogenization heat treatment and continuous extrusion to prepare extruded slabs; (3) The extruded slab is subjected to a first cold rolling, a two-stage aging heat treatment, and a second cold rolling process to obtain the Cu-Ni-P alloy strip; the total deformation in the first cold rolling is 70-95%; in the two-stage aging process, the first aging temperature is 200-300℃ and the aging time is 3-6h, the second aging temperature is 300-500℃ and the aging time is 1-4h; the total deformation in the second cold rolling is 40-70%.

2. The method for manufacturing Cu-Ni-P alloy strip as described in claim 1, characterized in that, In step (1), the casting temperature in the upward continuous casting is 1160-1200℃, and the diameter of the casting rod is 25-30mm.

3. The method for manufacturing Cu-Ni-P alloy strip as described in claim 1, characterized in that, In step (2), the heat treatment temperature in the homogenization heat treatment is 850-900℃ and the heat treatment time is 3-5h; the extrusion wheel speed in the continuous extrusion slab is 3-5r / min and the preheating temperature of the extrusion die is 450-650℃.

4. The method for manufacturing Cu-Ni-P alloy strip as described in claim 1, characterized in that, In step (2), the thickness of the extruded slab obtained after continuous extrusion is 12-14 mm.

5. The method for manufacturing Cu-Ni-P alloy strip as described in claim 1, characterized in that, In step (3), the thickness of the Cu-Ni-P alloy strip obtained after sequentially performing one cold rolling, two-stage aging heat treatment, and two cold rolling processes is 0.2-1.5 mm.

6. A Cu-Ni-P alloy strip manufactured by the manufacturing method of any one of claims 1-5.

7. The application of the Cu-Ni-P alloy strip as described in claim 6 in the fields of integrated circuits, rail transportation, aerospace, and communications.

8. The application as described in claim 7, characterized in that, The applications include lead frames, automotive connectors, and heat spreaders.

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