High-strength high-conductivity copper alloy plate strip and manufacturing method thereof

Abstract

The invention provides a high-strength and high-conductivity copper alloy plate strip which comprises 0.1-0.4 wt% of Ni, 0.1-0.4 wt% of Fe, 0.05-0.3 wt% of P, 0.01-0.15 wt% of Mg, one or more elements selected from Sn, Cr, Zr and Ti, the total amount of the elements is 0.2 wt% or below, and the balance is Cu and unavoidable impurities. The components of the copper alloy plate meet the proportional relation of the following formulas (1) and (2): 0.5 < = ({Ni} / {Fe}) < = 2.0... (1), 3.0 < = ({Ni} + {Fe}) / {P} < = 4.5... (2), wherein {Ni}, {Fe} and {P} respectively represent the mass percent of each element in the copper alloy plate. The copper alloy plate strip is excellent in comprehensive performance, the electric conductivity of the copper alloy plate strip is 60% IACS or above, the tensile strength of the copper alloy plate strip is 600 MPa or above, and meanwhile the copper alloy plate strip has good heat resistance and bending processability.

Description

Technical Field

[0001] The present invention relates to a high-strength and high-conductivity Cu-Ni-Fe-P alloy plate and strip material suitable for use as materials for electrical and electronic components such as integrated circuit lead frames, various connectors, and heat dissipation components, and a method for manufacturing the same. The copper alloy plate and strip material has high strength, good conductivity, heat resistance, and bendability. Background Art

[0002] In recent years, with the rapid development of integrated circuits and communication industries, electrical and electronic components such as connectors, lead frames, and heat dissipation components tend to be high current, dense, miniaturized, and lightweight, which puts higher requirements on the performance of copper alloy plates and strips: higher conductivity and strength, good heat resistance and bending processability, etc. Specifically, the conductivity is required to be above 60% IACS (preferably above 65% IACS); the tensile strength is required to be above 600MPa (preferably above 650MPa), the heat resistance temperature is above 500℃, and the ratio of the minimum bending radius R to the plate thickness t without cracking is R / t below 2.0.

[0003] At present, the copper alloys with medium-to-high strength and medium-to-high conductivity widely used in the industrial field mainly include Cu-Fe-P series, Cu-Cr series and Cu-Ni-Si series. Among them, Cu-Fe-P series alloys are widely used in lead frame materials (the representative alloy is C19400), with a conductivity of 60-70% IACS and low tensile strength (380-480MPa). Cu-Cr series alloys have both high conductivity (>80% IACS) and strength (480-560MPa), but the Cr element is easily oxidized and burned, which will cause various defects and uneven performance of the alloy during the production process. Cu-Ni-Si series alloys (the representative alloy is C70250) have high strength (600-750MPa) and corresponding conductivity (55-40% IACS).

[0004] The above three alloy systems have undergone extensive and in-depth research, and dozens of improved new alloys have been developed based on them. There are two basic methods: one is the trace element method of adding trace elements such as Sn, Zn, Zr, Mg, Ag, Ti, Co and rare earth elements not exceeding 0.1wt%; the other is to improve the quality (i.e., the strong rolling method of increasing the final rolling rate). The result is that the characteristics are improved, but still cannot meet the requirements. For example, the tensile strength of Cu-Fe-P alloy cannot reach 540MPa, whether it is the trace element method or the strong rolling method; the tensile strength of Cu-Cr alloy can be increased to about 580MPa by adding 0.1wt% Zr (such as C18150) and 0.1wt% Ag (C18080), but it cannot reach 600MPa; the world's highest strength Cu-Cr alloy is MZC1 of Mitsubishi Shindoh Co., Ltd., which can reach 600-630MPa by strong rolling method, but its bending processability is significantly deteriorated (R / t=3.75-6.25), and it can only be used in a small range without bending. The tensile strength of Cu-Ni-Si alloy is improved, but the conductivity cannot reach 60% IACS.

[0005] The Cu-Ni-P alloys developed in recent years (representative alloys are C19000 and KLF170 of Kobe Steel) have higher strength (600-650MPa) and corresponding electrical conductivity (60-65% IACS). However, due to the relatively large amount of added elements exceeding 1wt% (C19000: Cu-1.0% Ni-0.2% Fe; KLF170: Cu-0.8Ni-0.13P-0.1Zn-0.1Fe), the electrical conductivity is difficult to exceed 65% IACS, and too many added elements can easily lead to low heat resistance and bending workability.

[0006] Therefore, considering that it is difficult for existing high-strength and high-conductivity copper alloys to have both conductivity of more than 60% IACS, strength exceeding 600 MPa, and good heat resistance and bending workability, the present invention was developed and completed. Summary of the invention

[0007] Based on detailed investigation and research, the inventors found that Cu-Ni-Fe-P alloy has both the high strength of Cu-Ni-P alloy and the high conductivity of Cu-Fe-P alloy. By adjusting the ratio of Ni, Fe, and P elements and applying a reasonable deformation heat treatment process, the (Ni, Fe) 2 The precipitation strengthening effect of the P phase can produce high-performance copper alloys with excellent electrical conductivity, strength, heat resistance and bending performance. In addition, adding an appropriate amount of Mg to the Cu-Ni-Fe-P alloy can refine the grain size and (Ni,Fe) 2The size of the P precipitated phase is increased, thereby improving the strength of the alloy and improving the high temperature softening resistance. The present invention is completed based on these findings.

[0008] The present invention provides a high-strength and high-conductivity copper alloy plate and strip material, which contains 0.1-0.4wt% Ni, 0.1-0.4wt% Fe, 0.01-0.15wt% Mg, 0.05-0.3wt% P, and further contains one or more elements selected from Sn, Cr, Zr, Zn and Ti, and the total amount thereof is less than 0.2wt%, and the rest is composed of Cu and unavoidable impurities. The components of the copper alloy plate and strip material satisfy the following ratio relationship of formula (1) and (2):

[0009] 0.5≤({Ni} / {Fe})≤2.0……(1)

[0010] 3.0≤({Ni}+{Fe}) / {P}≤4.5……(2)

[0011] Wherein {Ni}, {Fe} and {P} represent the mass percentage of each element in the copper alloy plate.

[0012] The above-mentioned high-strength and high-conductivity copper alloy sheet and strip has a conductivity of more than 60% IACS, a tensile strength of more than 600 MPa, a heat-resistant temperature of more than 500° C., and a minimum bending radius to sheet thickness ratio R / t of less than 2.0.

[0013] The electrical conductivity is measured according to the method specified in the JIS H0505 standard. The tensile strength is measured by cutting samples in the rolling direction of the plate and strip and following the test process specified in the JIS Z2241 standard. The heat-resistant temperature is the temperature corresponding to 80% of the initial hardness before heat resistance after 30 minutes of heat preservation at Vickers hardness. As for the evaluation of bending workability, test samples are obtained from the rolling direction (LD) and perpendicular to the rolling direction (TD) of the plate and strip, and the sample width is uniformly 10mm. The bending test is performed according to the 90° W-type bending processing method specified in the JIS H3110 standard, and the evaluation is performed by measuring the ratio R / t of the minimum bending radius R without cracking and the plate thickness t.

[0014] Provided is a method for manufacturing the copper alloy plate and strip, which comprises sequentially performing the following steps on the copper alloy having the above composition: a semi-continuous casting method is used to cast a billet, hot rolling is performed after heating at 920-980°C for 3-5h, cold rolling is performed, a solid solution treatment is performed in the temperature range of 880-970°C for 0.5-2.5min, an aging treatment is performed in the temperature range of 350-500°C for 3-10h, and finally cold rolling is performed and low temperature annealing is performed after the final cold rolling.

[0015] During the hot rolling process, the final rolling temperature is controlled between 650-800° C. In the first three passes, the processing rate of each pass is between 10-20%, and the processing rate of each subsequent pass is controlled between 25-35%.

[0016] In the above low temperature annealing process, the copper alloy sheet and strip can be annealed at 400-500°C for a short time of 10-70s, or annealed in a bell furnace at 150-350°C for several hours.

[0017] The copper alloy sheet and strip prepared according to the present invention has excellent comprehensive properties. The alloy is designed to respond to and meet the higher requirements for materials used in electrical and electronic components in the future, namely, the requirements of bearing higher loads, achieving higher integration, smaller size and lighter construction. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0019] 1. Alloy composition

[0020] Nanoscale phosphides can effectively improve the comprehensive properties of alloys. According to detailed research results, both Ni (nickel) and Fe (iron) can react with P (phosphorus) to form phosphides, namely Ni 2 P and Fe 2 P. When Ni and Fe are added to Cu-P alloy at the same time, it can promote the formation of (Ni,Fe) 2 P precipitation phase. Compared with the matrix with only a single type of phosphide (Ni 2 P or Fe 2 P), (Ni,Fe) 2 The size of the P precipitated phase is smaller and the distribution is more uniform, so it has a more significant precipitation strengthening effect. It is worth noting that the Ni and Fe elements have a significant effect on the electrical conductivity of the alloy, and the Ni in the matrix 2 P and Fe 2 Phosphides such as P are prone to coarsening, so simply increasing the content of Ni, Fe, and P is not enough to significantly improve the mechanical properties of the alloy. On the contrary, this approach may also lead to a sharp drop in the electrical conductivity of the alloy.

[0021] When the element content of Ni and Fe is less than 0.1wt%, the precipitation strengthening effect is insufficient, resulting in limited strength improvement of the alloy; and when the content exceeds 0.4wt%, it is easy to cause the electrical conductivity, heat resistance and bending processability of the alloy to decrease. Therefore, in order to ensure the improvement of alloy performance, the Ni content should be controlled between 0.1-0.4wt%, and the Fe content should also be maintained in the range of 0.1-0.4wt%. The purpose of the present invention is to make full use of the superposition effect of precipitation strengthening of Ni-P and Fe-P compounds, so the content of Fe and Ni cannot differ too much, so the content of Ni and Fe must meet the conditions specified in formula (1).

[0022] 0.5≤({Ni} / {Fe})≤2.0……(1)

[0023] If the {Ni} / {Fe} ratio is less than 0.5 or greater than 2.0, that is, the content of Ni and Fe differs too much, the resulting alloy properties are close to Cu-Ni-P alloy or Cu-Fe-P alloy, and the purpose of the present invention cannot be achieved.

[0024] Studies have shown that P and Ni, Fe elements mainly form (Ni, Fe) 2 The ratio of the sum of the number of atoms of (Ni, Fe) to the number of P atoms in the precipitate mainly composed of P is 3:1. Therefore, in order to achieve the best precipitation strengthening effect, the content of the P element needs to be adjusted so that the ratio of the total number of atoms of (Ni, Fe) to the number of P atoms is as close to 3:1 as possible. In the present invention, when the content of each element is expressed in mass percentage (wt%), the content of the P element should satisfy the ratio range specified by the following formula (2).

[0025] 3.0≤({Ni}+{Fe}) / {P}≤4.5……(2)

[0026] According to the content of Ni and Fe and the constraint of formula (2), it can be determined that the P content should be controlled between 0.05-0.3wt%. If the P content is less than 0.05%, the hardness of the alloy will be low; on the contrary, if the P content exceeds 0.3wt%, the conductivity of the alloy will be significantly reduced and the risk of cracking will increase during the hot rolling process.

[0027] Mg element plays a major role in refining grain size and precipitated phase size in the matrix. If the Mg content deviates from the ideal range, whether it is too high or too low, it will lead to a decrease in the electrical conductivity or strength of the alloy. Therefore, the Mg content should be within the range of 0.01-0.15wt%.

[0028] For other elements, one or more elements of Sn, Cr, Zr, Zn and Ti can be selectively added according to the needs of specific application scenarios. Specifically, Cr, Zr and Ti have the effect of refining grains and improving the heat resistance of alloys; Sn exhibits a good solid solution strengthening effect and can significantly improve the strength of alloys; Zn can effectively prevent the electroplating layer on the surface of the plate and strip from falling off. When adding one or more of these elements, in order to ensure that the above effects are fully exerted, their total content should preferably not be less than 0.01wt%. However, excessive content of the above elements may lead to a decrease in conductivity. Therefore, the total content of these elements should be controlled within a range of no more than 0.2wt%, more preferably between 0.05-0.15wt%.

[0029] 2. Characteristics

[0030] 1. Conductivity and strength:

[0031] At present, the medium-high strength and medium-high conductivity copper alloy plates and strips widely used in electrical and electronic components such as connectors, lead frames, power terminals, and heat dissipation components can be mainly divided into two categories: the first type of materials includes alloy series such as C19200, C14415 and C18150, which are characterized by conductivity > 80% IACS and strength between 350-560MPa. The second type is mainly represented by Cu-Ni-Si series alloys represented by C70250 and C70350, with a strength of 600-750MPa and a conductivity of 40%-50% IACS. As electrical and electronic components are increasingly moving towards high density, miniaturization and lightweight, the strength requirements for copper alloy plates and strips are constantly rising, which makes it difficult for the strength indicators of the first type of copper alloys to meet current application requirements. In addition, under the background of the rapid development of high-current high-speed transmission technology and fast charging technology, the conductivity of the second type of alloys is also gradually revealing its limitations. In this context, the market demand for copper alloy sheets and strips with more balanced properties is growing. Specifically, the market is currently highly concerned about and urgently needs a high-performance copper alloy material with a conductivity of more than 60% IACS, a tensile strength of more than 600 MPa, and good bending performance. This has become a new trend and focus demand in the market.

[0032] In order to deal with the temperature rise caused by high-speed transmission of large current, on the one hand, the electrical conductivity (heat dissipation) of the alloy is improved, and at the same time, the heat resistance of the alloy is also required, that is, at a certain temperature, the strength (hardness) of the alloy material cannot be excessively reduced. Specifically, the heat resistance temperature is not less than 500°C.

[0033] 2. Bending processability:

[0034] When conducting the bending performance test, it is first necessary to clarify the two directions in which the plate and strip surface is parallel (LD) and perpendicular (TD) to the rolling direction, and ensure that the bending performance in these two directions meets the standards: When conducting a 90° W-type bending test, the ratio R / t between the minimum bending radius R that does not cause cracks and the plate thickness t should be maintained below 2.0. The bending performance in the LD direction mentioned here means that when the specimen is cut, the length direction of the specimen is consistent with the rolling direction, and when the bending process is performed, the bending axis is along the TD direction. Correspondingly, the bending performance in the TD direction means that when the specimen is cut, the length direction of the specimen is perpendicular to the rolling direction, and when the bending process is performed, the bending axis is along the LD direction.

[0035] 3. Manufacturing method

[0036] The copper alloy sheet and strip of the present invention can be manufactured through the following standardized production process, namely: melting / casting - hot rolling - cold rolling - solution treatment - aging treatment - final cold rolling - low temperature annealing.

[0037] However, it should be emphasized that the precise control of several key process conditions in this production process is crucial. In addition, although not described in detail above, according to actual application requirements, after the hot rolling step, milling treatment can be selectively performed; after the heat treatment, pickling, grinding, degreasing or bending straightening can be selectively performed. The following will explain each process step in more detail.

[0038] 1. [Melting casting]

[0039] Conventional copper alloy longitudinal semi-continuous casting method can meet production needs. In order to effectively prevent the oxidation of elements such as P and Mg, charcoal can be added to the smelting furnace and launder, and inert gases such as nitrogen can be introduced for protection.

[0040] 2. [Hot rolling]

[0041] Generally, the heating temperature of copper alloy is between 900-950℃. However, for the copper alloy developed by the present invention, since there are a large number of coarse (Ni,Fe)2P precipitates solidified in the interdendritic gaps in its casting structure, this precipitate has a higher solid solution temperature. Therefore, the heating temperature of the copper alloy described in the present invention needs to be higher than that of conventional copper alloys and should be controlled between 920-980℃. If the heating temperature of the ingot fails to reach this standard, (Ni,Fe) 2The P compound will not be able to be completely dissolved, which will significantly reduce the precipitation phase in the subsequent aging treatment, and ultimately lead to insufficient strength of the alloy. On the other hand, if the heating temperature is too high, the phosphide will tend to segregate in the grain boundary area. This grain boundary segregation phenomenon will cause the phosphide to aggregate at the grain boundary, thereby increasing the brittleness of the ingot and greatly increasing the risk of the ingot breaking during subsequent processing. Therefore, precise control of the heating temperature is crucial to ensure the stability and superiority of the alloy performance.

[0042] In the initial three rolling passes, the processing rate of each pass must be strictly controlled to maintain it within the range of 10%-20%. On the one hand, if the processing rate is too low, the dislocation density inside the plate and strip will not be sufficient to provide sufficient driving force for recrystallization, and the material will be prone to cracking as the hot rolling process progresses; on the other hand, if the processing rate is too high, it may directly cause cracking during the rolling process. Therefore, controlling the processing rate of the initial three passes between 10%-20% can not only effectively avoid the risk of cracking, but also promote the recrystallization process of the alloy, thereby ensuring the stability of the rolling process and the good performance of the material.

[0043] Due to (Ni, Fe) 2 The precipitation temperature of P is relatively high. In order to ensure its precipitation effect and optimization of material properties, the final rolling temperature of the plate and strip should be controlled between 650-800℃, and the final rolling pass processing rate should be about 30%. When rolling deformation is carried out in this temperature range, the precipitation process and the increase of dislocation density will proceed simultaneously, which constitutes a dynamic precipitation mechanism. In this process, dislocations, as precipitation nucleation sites, can significantly promote the increase of precipitate density. In the subsequent aging treatment stage, the increase in precipitation amount and the uniformity of distribution will be further promoted, thereby giving the alloy higher strength. On the contrary, if rolling deformation is not carried out in this temperature range or the rolling rate is lower than 30%, the nucleation site of the precipitate will be relatively reduced during the subsequent aging treatment, thereby weakening the precipitation strengthening effect and having an adverse effect on the final performance of the alloy. Therefore, strict control of the final rolling temperature and pass processing rate is crucial to ensure the effective precipitation of precipitates and the optimization of alloy properties.

[0044] 3. [Cold rolling]

[0045] This process cold-rolls the material to a predetermined size based on the final product's dimensional specifications and the desired final processing rate.

[0046] 4. [Solution treatment]

[0047] In order to achieve the re-solidification of a small amount of Ni-P and Fe-P compounds precipitated during the hot working process, a solution treatment process is required. The appropriate solution treatment temperature varies according to the specific composition of the alloy. Within the scope of the alloy composition of the present invention, the ideal solution treatment temperature range is 800-1000°C, and the treatment time can be adjusted in the range of a few seconds to a few minutes. The solution treatment time is affected by the treatment temperature and the size of the material, and can be determined by experimental means. Specifically, a judgment can be made by analyzing the microstructure after solution treatment: an accurate method is to use a transmission electron microscope to observe the presence or absence of precipitates; another simpler method is to perform metallographic observation, with the recrystallized grain diameter reaching about 10μm as the criterion for determining that the precipitates have basically completed the solution.

[0048] If the hot rolling temperature is high and the cooling rate after hot rolling is fast, resulting in a decrease in the number of precipitates, this step can be omitted. In addition, if the final product has relatively high requirements for electrical conductivity and relatively low requirements for strength, this solution treatment step can also be considered to be omitted.

[0049] 5. [Aging Processing]

[0050] The main purpose of aging treatment is to promote (Ni, Fe) 2 The P phase is precipitated as much as possible to achieve the purpose of improving the strength and conductivity of the material. Therefore, the aging treatment needs to be carried out under conditions that can optimize the conductivity and strength of the alloy. It should be noted that if the aging treatment temperature is too high or the aging time is prolonged, it is easy to cause over-aging, which in turn causes the strength of the alloy to decrease; conversely, if the aging temperature is too low or the aging time is too short, the precipitation process will be insufficient and it will be difficult to achieve the ideal performance indicators. Specifically, in order to obtain the best aging effect, the aging treatment temperature should preferably be controlled within the range of 350-500°C, and the aging treatment time should be roughly maintained between 3-10h to ensure that excellent results can be obtained.

[0051] 6. [Final cold rolling]

[0052] In order to further improve the strength of the material, a final cold rolling with a total rolling rate of 30-60% is performed after aging treatment. As the rolling rate increases, the strength of the material increases, but at the same time, its heat resistance and bending performance will decrease. After detailed research and investigation by the inventor, it is found that when the rolling rate is controlled between 30-60%, the optimization goals of strength, conductivity and bending performance pursued by the present invention can be met at the same time.

[0053] In addition, the final plate thickness of the copper alloy involved in the present invention can be set in the range of 0.1-0.8 mm, and the most ideal plate thickness range is between 0.1-0.5 mm.

[0054] 7. [Low temperature annealing]

[0055] After the final cold rolling, low-temperature annealing is required to effectively reduce and eliminate the residual stress inside the plate and strip, and to improve the heat resistance and bending performance of the material. At the same time, the low-temperature annealing process can effectively reduce the vacancy concentration and dislocation density in the slip plane area, thereby improving the electrical conductivity of the material while maintaining the strength of the material without a significant decrease. For this alloy, the low-temperature annealing process is recommended to be set in the range of 400-500°C for a continuous annealing treatment of 10-70s, or a bell furnace annealing for several hours in the temperature range of 150-350°C. It is worth noting that if the annealing temperature is set too high, it may cause excessive softening of the plate; conversely, if the temperature is set too low, the expected annealing effect may not be achieved.

[0056] 4. Embodiment

[0057] The ingots with the composition shown in Table 1 were cast using a vertical semi-continuous casting machine. Subsequently, the head and tail of the ingot were cut off, and hot rolling was carried out immediately. After the hot rolling was completed, the oxide layer on the surface of the ingot was removed by milling. After that, the ingot was further cold rolled to the required thickness specification. In addition, some embodiments were subjected to a solid solution treatment of 800-1000°C. For alloys with different compositions, the metallographic structure under different solid solution treatment temperatures and times was observed experimentally in advance, and finally the temperature and time corresponding to the average grain diameter of 8-15μm were selected as the set temperature of the heating zone and the soaking zone of the continuous annealing furnace. The ratio of the furnace length of the heating zone and the soaking zone to the plate passing speed determined the corresponding treatment time. Then, by adjusting the temperature and time parameters of the aging treatment, the hardness of the alloy reached a peak value. The samples after aging treatment were then subjected to a final cold rolling process with a rolling rate of 30-60%, and low-temperature annealing was performed after cold rolling. In the whole process, according to actual needs, a series of auxiliary processes such as pickling, degreasing, straightening, trimming, etc. are carried out in time to ensure product quality. Finally, the characteristics of the obtained plate and strip are evaluated. The plate thickness of all samples is 0.20mm. The main manufacturing conditions and properties of each sample are shown in Table 2. In addition, the characteristics of representative high-strength and high-conductivity copper alloy materials circulating on the market, such as MZC1 and MSP1 alloys, are also evaluated and compared.

[0058]

Table 1

[0059]

[0060] Note: The underline indicates that it is beyond the scope specified in the present invention.

[0061] The performance indicators of different samples were measured, namely electrical conductivity, tensile strength, and bending processability.

[0062] [Electrical conductivity]: Measured according to the method specified in JIS H0505.

[0063] [Tensile strength]: Measured according to the method specified in JIS Z2241.

[0064] [Heat-resistant temperature]: Place the sample in a temperature range of 100-600℃ for 30 minutes (temperature interval is 50℃), and then measure the hardness. As the heating temperature gradually increases, the hardness of the sample decreases. The temperature corresponding to the hardness of the sample after heating is 80% of the hardness before heating is the heat-resistant temperature.

[0065] [Bending Processability]: Plate-shaped specimens (10 mm in width) cut in the length directions LD and TD were bent according to the 90° W-type bending method specified in JIS H3110. The surface and cross section of the specimen after bending were observed under an optical microscope at 100 times. The minimum bending radius R without cracking was obtained. The ratio R / t of the minimum bending radius R and the plate thickness t was used as an evaluation of the bending processability. The smaller the R / t value, the better the bending processability.

[0066] The results of the characteristic evaluation are shown in Table 2.

[0067]

Table 2

[0068]

[0069] Note: The underline indicates that it is beyond the scope specified in the present invention.

[0070] As shown in Table 2, all the inventive examples, under the premise of meeting the composition requirements and manufacturing process conditions defined in the present invention, show excellent performance of electrical conductivity exceeding 60% IACS and tensile strength not less than 600 MPa; when the solid solution treatment process is not adopted, the electrical conductivity exceeds 70% IACS, and when the solid solution treatment process is adopted, the tensile strength exceeds 650 MPa; and the heat resistance temperature exceeds 500°C, and the bending processing performance in both LD and TD directions is shown to be less than 2.0.

[0071] In comparison, the reason why Comparative Examples No. 21-No. 25 failed to show ideal performance characteristics is that the Ni, Fe, P and Mg element contents or ratios of these examples exceeded the parameter range specified in the present invention. Specifically, No. 21 lacks the addition of Mg element, which leads to a significant increase in the internal grain size and precipitation phase size of the alloy, thereby reducing the tensile strength and heat resistance of the alloy. Comparative Examples No. 22 and No. 23 have improper regulation of the (Ni+Fe) / P ratio, that is, a relative excess of one component of the (Ni+Fe) and P elements, which leads to a reduction in the number of precipitation phases, thereby reducing the strength and conductivity of the alloy. Comparative Example No. 24 cracked the ingot during hot rolling due to the excessive P content. As for Comparative Example No. 25, its Mg element content is too high, which has an adverse effect on the electrical conductivity of the alloy.

[0072] Comparative Examples No. 31 to 33 are examples in which alloys having the same composition as Inventive Example No. 1 are prepared because their manufacturing process conditions are outside the prescribed range of the present invention and good properties are not obtained.

[0073] Specifically, the hot rolling temperature of Comparative Example No. 31 was too low, resulting in insufficient solid solution of the alloy, which in turn caused the alloy's strength performance to fail to reach the expected level. The hot rolling temperature of Comparative Example No. 32 was too high, which caused cracking during the hot rolling process, making it impossible to carry out subsequent rolling, heat treatment, and performance evaluation. In addition, the aging temperature of Comparative Example No. 33 was set too low, which affected the internal (Ni, Fe) 2 The sufficient precipitation of the P phase directly leads to the alloy having a strength and conductivity significantly lower than that of Invention Example No.1.

[0074] Comparative Examples No. 41 and No. 42 correspond to MSP1 and MZC1 of Mitsubishi Shindoh Co., Ltd. It is not difficult to find that at least one of the key indicators of strength, conductivity, heat resistance and bending performance is insufficient to a certain extent compared with the examples of the present invention.

Claims

1. A high-strength and high-conductivity copper alloy sheet and strip, characterized in that: It contains 0.1-0.4wt% Ni, 0.1-0.4wt% Fe, 0.05-0.3wt% P, and the rest is Cu and unavoidable impurities. The components of the copper alloy plate satisfy the following ratio relationship of formula (1) and (2): 0.5≤({Ni} / {Fe})≤2.0……(1) 3.0≤({Ni}+{Fe}) / {P}≤4.5……(2) Wherein {Ni}, {Fe} and {P} represent the mass percentage of each element in the copper alloy plate and strip respectively.

2. The high-strength and high-conductivity copper alloy sheet and strip according to claim 1, characterized in that: It also contains 0.01-0.15 wt% Mg.

3. The high-strength and high-conductivity copper alloy sheet and strip according to claim 1 or 2, characterized in that: It also contains one or more elements selected from Sn, Cr, Zr, Zn and Ti, and the total amount thereof is less than 0.2 wt%.

4. The high-strength and high-conductivity copper alloy sheet and strip according to claim 3, characterized in that: The total amount of one or more elements of Sn, Cr, Zr, Zn and Ti is 0.05-0.15 wt%.

5. The high-strength and high-conductivity copper alloy sheet and strip according to claim 1 or 2, characterized in that: The electrical conductivity of the copper alloy sheet and strip is above 60% IACS, the tensile strength is above 600 MPa, the heat resistance temperature is above 500°C, and the minimum bending radius to plate thickness ratio R / t is less than 2.

0.

6. The method for manufacturing the high-strength and high-conductivity copper alloy sheet and strip according to any one of claims 1 to 5, characterized in that: It includes the following steps performed in sequence: S1, semi-continuous casting; S2, hot rolling after heating at 920-980℃ for 3-5h; S3, cold rolled; S4, solution treatment for 0.5-2.5 min in the temperature range of 880-970°C; S5, aging treatment at 350-500℃ for 3-10h; S6, final cold rolling and low temperature annealing after final cold rolling.

7. The method for manufacturing a high-strength and high-conductivity copper alloy sheet and strip according to claim 6, characterized in that: During the S2 hot rolling process, the final rolling temperature is controlled between 650-800°C. In the first three hot rolling passes, the processing rate of each pass is between 10-20%, and the processing rate of each subsequent pass is controlled between 25-35%.

8. The method for manufacturing a high-strength and high-conductivity copper alloy sheet and strip according to claim 6, characterized in that: During the final cold rolling in S6, the final cold rolling reduction ratio is controlled between 15% and 35%.

9. The method for manufacturing a high-strength and high-conductivity copper alloy sheet and strip according to claim 6, characterized in that: In the S6 low temperature annealing process, the copper alloy sheet and strip are continuously annealed at 400-500°C for 10-70s, or annealed in a bell furnace at 150-350°C for several hours.

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