JP2016053220A - Copper alloy sheet excellent in conductivity, stress relaxation characteristic and molding processability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper alloy sheet having high strength, high conductivity and excellent press relaxation characteristic, and a high-current electronic component and an electronic component for heat release using the copper alloy sheet.SOLUTION: There is provided a copper alloy sheet containing at least one or more kinds of Ni and Co of 0.8 to 5.0 mass% in total, Si of 0.2 to 1.5 mass% and the balance copper with inevitable impurities, having 0.2% bearing force σof 500 MPa or more, and a conductivity of 30%IACS or more, a relationship between a spring deflection limit Kb (MPa) and 0.2% bearing force σ(MPa) given Kb≥(σ-100), and I/Iof 5.0 or less where Iis diffraction integrated strength of a (hkl) face calculated in a thickness direction on a surface by using an X-ray diffraction method.SELECTED DRAWING: None

Description

  TECHNICAL FIELD The present invention relates to a copper alloy plate and electronic parts for energization or heat dissipation, and in particular, electronic parts such as terminals, connectors, relays, switches, sockets, bus bars, lead frames, heat sinks, etc. mounted on electric machines / electronic devices, automobiles and the like. The present invention relates to a copper alloy plate used as a material for the above and an electronic component using the copper alloy plate. Among these, copper alloys suitable for use in high current electronic parts such as high current connectors and terminals used in electric vehicles, hybrid cars, etc., or in heat dissipation electronic parts such as liquid crystal frames used in smartphones and tablet PCs. The present invention relates to a plate and an electronic component using the copper alloy plate.

  Electrical and electronic equipment, automobiles, etc. have built-in parts for conducting electricity or heat, such as terminals, connectors, switches, sockets, relays, bus bars, lead frames, heat sinks, etc. These parts are made of copper alloy. It is used. Here, electrical conductivity and thermal conductivity are in a proportional relationship.

  In recent years, with the miniaturization of electronic components, the cross-sectional area of the copper alloy in the current-carrying part tends to be small. When the cross-sectional area becomes small, heat generation from the copper alloy when energized increases. In addition, electronic parts used in fast-growing electric vehicles and hybrid electric vehicles include parts through which a remarkably high current flows, such as a connector of a battery unit, and heat generation of a copper alloy during energization is a problem. When the heat generation becomes excessive, the copper alloy is exposed to a high temperature environment.

  In an electrical contact of an electronic component such as a connector, a deflection is given to the copper alloy plate, and a contact force at the contact is obtained by a stress generated by the deflection. When a bent copper alloy is held at a high temperature for a long time, the stress, that is, the contact force is lowered due to the stress relaxation phenomenon, and the contact electric resistance is increased. In order to cope with this problem, the copper alloy is required to be more excellent in conductivity so that the amount of generated heat is reduced, and is also required to be superior in stress relaxation resistance so that the contact force does not decrease even if heat is generated.

  On the other hand, for example, a heat radiating component called a liquid crystal frame is used for a liquid crystal of a smartphone or a tablet PC. Even in such a copper alloy plate for heat dissipation, when the stress relaxation resistance is increased, creep deformation of the heat sink due to external force is suppressed, and the protection against liquid crystal components, IC chips, etc. arranged around the heat sink is improved. You can expect effects such as.

  Furthermore, the copper alloy sheet becomes an electronic component for energization or heat dissipation through forming processing such as bending and drawing, but with the miniaturization and high functionality of the component, more excellent forming workability is achieved. There is a demand for alloy plates.

  A Corson alloy is known as a copper alloy having high electrical conductivity, high strength, and relatively good stress relaxation resistance and moldability. A Corson alloy is an alloy in which an intermetallic compound such as Ni—Si, Co—Si, or Ni—Co—Si is precipitated in a Cu matrix.

  Recent research on the Corson alloy is mainly aimed at improving the bending workability, and various techniques for developing the {001} <100> orientation (Cube orientation) have been proposed as measures for that purpose. For example, in patent document 1 (Unexamined-Japanese-Patent No. 2006-283059), the area ratio of Cube direction is controlled to 50% or more, and the bending workability is improved. Patent Document 2 (Japanese Patent Laid-Open No. 2010-275622) improves the bending workability by controlling the X-ray diffraction intensity of (200) (synonymous with {001}) to be equal to or higher than the X-ray diffraction intensity of the copper powder standard sample. . In Patent Document 3 (Japanese Patent Laid-Open No. 2011-17072), the area ratio of the Cube orientation is controlled to 5 to 60%, and at the same time, the area ratios of the Brass orientation and Copper orientation are both controlled to 20% or less to improve bending workability. doing. In Patent Document 4 (Japanese Patent No. 4857395), the area ratio of the Cube orientation is controlled to 10 to 80% at the center in the thickness direction, and at the same time, the area ratios of the Brass orientation and Copper orientation are both controlled to 20% or less. And notch bendability is improved. In patent document 5 (WO2011 / 068121), Cube azimuth | direction area ratio in the position of 1/4 of the whole in the surface layer and depth position of material is set to W0 and W4, respectively, and W0 / W4 is 0.8-1.5. , W0 is controlled to 5 to 48%, and the average crystal grain size is adjusted to 12 to 100 μm to improve the 180-degree adhesion bendability. In Patent Document 6 (WO 2011/068134), the Young's modulus is adjusted to 110 GPa or less and the bending deflection coefficient is adjusted to 105 GPa or less by controlling the area ratio of the (100) plane facing the rolling direction to 30% or more.

JP 2006-283059 A JP 2010-275622 A JP 2011-17072 A Japanese Patent No. 4857395 International publication WO2011 / 068121 International publication WO2011 / 068134

  However, although the Corson alloy has a relatively good stress relaxation resistance, the level of the stress relaxation resistance is not always sufficient for the use of a component that conducts a large current or a component that dissipates a large amount of heat. . In particular, no Corson alloy having good stress relaxation resistance and moldability has been reported so far.

  Therefore, the present invention aims to provide a copper alloy plate having high strength, high conductivity, and excellent stress relaxation resistance, and specifically provides a Corson alloy having improved stress relaxation resistance. This is the issue. Another object is to improve the moldability in addition to the stress relaxation resistance. It is another object of the present invention to provide an electronic component suitable for high current use or heat dissipation use.

  As a result of intensive studies, the present inventor has found that the stress relaxation resistance is improved by adjusting the spring limit value and the specific crystal orientation for the Corson alloy having high strength and high conductivity. Furthermore, it has been found that, when the Cube orientation is developed on the surface of the Corson alloy having improved stress relaxation resistance, the moldability is improved.

The present invention completed on the basis of the above knowledge,
(1) One or more of Ni and Co are added in a total of 0.8 to 5.0 mass%, Si is contained in 0.2 to 1.5 mass%, the balance is made of copper and inevitable impurities, and is 500 MPa or more. has a 0.2% proof stress sigma _y, and 30% IACS or more conductivity, spring limit value Kb (MPa) 0.2% proof stress sigma _y relationship between (MPa) is, Kb ≧ (σ _y -100) I ₍₁₁₁₎ / I ₍₃₁₁₎ is 5.0 or less, where I _(hkl) is the integrated diffraction intensity of the (hkl) plane obtained in the thickness direction on the surface using the X-ray diffraction method. A copper alloy plate characterized by being.
(2) When the integrated diffraction intensity of the (hkl) plane obtained for copper powder using X-ray diffraction is I _{0 (hkl)} , I ₍₂₀₀₎ / I _{0 (200)} ≧ 1.0 (1) The copper alloy plate characterized by these.
(3) (1) or (2) containing one or more of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, B, and Ag in a total amount of 3.0% by mass or less Copper alloy plate.
(4) A high-current electronic component using the copper alloy plate according to any one of (1) to (3).
(5) A heat dissipating electronic component using the copper alloy plate according to any one of (1) to (3).
I will provide a.

  According to the present invention, it is possible to provide a copper alloy plate having high strength, high conductivity, and excellent stress relaxation characteristics, and also having excellent formability, and an electronic component suitable for large current use or heat radiation use. Is possible. This copper alloy plate can be suitably used as a material for electronic parts such as terminals, connectors, switches, sockets, relays, bus bars, lead frames, heat sinks, etc. It is useful as a material for electronic parts that dissipate heat.

It is a graph which shows the relationship between the annealing temperature when the alloy which concerns on this invention is annealed at various temperatures, and tensile strength. It is a figure explaining the measurement principle of a stress relaxation rate. It is a figure explaining the measurement principle of a stress relaxation rate.

The present invention will be described below.
(Addition amount of Ni, Co and Si)
A copper alloy plate used as a material for a part that conducts a large current or a part that dissipates a large amount of heat needs to have a conductivity of 30% IACS or more and a 0.2% proof stress of 500 MPa or more.
Therefore, Ni and / or Co is added to the copper alloy plate of the present invention, and Si is further added. Ni, Co, and Si are precipitated as intermetallic compounds such as Ni—Si, Co—Si, and Ni—Co—Si by performing an appropriate aging treatment. The strength of the precipitate is improved by the action of the precipitate, and Ni, Co, and Si dissolved in the Cu matrix are reduced by the precipitation, so that the conductivity is improved.

  When the total amount of Ni and Co is less than 0.8% by mass or Si is less than 0.2% by mass, it becomes difficult to obtain a 0.2% yield strength of 500 MPa or more. When the total amount of Ni and Co exceeds 5.0% by mass or when Si exceeds 1.5% by mass, it becomes difficult to obtain a conductivity of 30% IACS or more. Therefore, in the Corson alloy according to the present invention, the total addition amount of one or more of Ni and Co is 0.8 to 5.0 mass%, and the addition amount of Si is 0.2 to 1.5 mass%. Yes. The total of one or more addition amounts of Ni and Co is more preferably 1.0 to 4.0 mass%, and the addition amount of Si is more preferably 0.25 to 0.90 mass%.

(Other additive elements)
The Corson alloy may contain one or more of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, B, and Ag in order to improve strength and heat resistance. However, if the addition amount is too large, the electrical conductivity may be reduced to be less than 30% IACS or the productivity of the alloy may be deteriorated. Therefore, the addition amount is preferably 3.0% by mass or less, more preferably Is 2.5% by mass or less. Moreover, in order to acquire the effect by addition, it is preferable to make addition amount 0.001 mass% or more in total amount.

(Spring limit value)
By adjusting the metal structure using the spring limit value as an index, the stress relaxation resistance of the copper alloy sheet is improved. In the copper alloy plate according to the present invention, when the spring limit value of the product is Kb (MPa) and the 0.2% proof stress is σ _y (MPa), the relationship of Kb ≧ (σ _y −100) Preferably, the stress relaxation resistance is improved by adjusting the relationship to Kb ≧ (σ _y −50). The upper limit value of Kb is not particularly limited, but usually does not exceed σ _y .

(Crystal orientation)
In the present invention, the θ / 2θ measurement is performed on the surface of the copper alloy plate by the X-ray diffraction method, and the integrated intensity (I _(hkl) ) of the diffraction peak in the predetermined orientation (hkl) plane is measured. Further, the integrated intensity (I _{0 (hkl)} ) of the diffraction peak on the (hkl) plane is also measured for copper powder as a random orientation sample.

(Crystal orientation and stress relaxation resistance)
By controlling the crystal orientation of the surface of the copper alloy plate with adjusted Kb, the stress relaxation resistance of the copper alloy plate is further improved. In the copper alloy sheet according to the present invention, the stress relaxation resistance is improved by adjusting I ₍₁₁₁₎ / I ₍₃₁₁₎ to 5.0 or less, preferably 2.0 or less. Although the lower limit of _{I (111) / I (311} ) is not limited in terms of the stress relaxation property _{improves, I (111) / I (} 311) typically takes a value of more than 0.01.

(Formability and crystal orientation)
In order to obtain good moldability, I ₍₂₀₀₎ / I _{0 (200)} is adjusted. It can be said that the higher the I ₍₂₀₀₎ / I _{0 (200)} , the more developed the Cube orientation. In the copper alloy sheet according to the present invention, when I ₍₂₀₀₎ / I _{0 (200)} is controlled to 1.0 or more, preferably 2.0 or more, the moldability is improved. The upper limit of _{I (200) / I 0 (} 200) , although in terms of moldability improved not regulated, I ₍₂₀₀₎ of Corson alloy of the present invention / I 0 ₍₂₀₀₎ is typically 10. 0 or less.

(Thickness)
The thickness of the product is preferably 0.1 to 2.0 mm. If the thickness is too thin, the cross-sectional area of the current-carrying part will decrease and heat generation will increase during energization, making it unsuitable as a material for connectors that carry large currents, and because it will deform with a slight external force, It is also unsuitable as a material. On the other hand, when the thickness is too thick, the molding process becomes difficult. From such a viewpoint, a more preferable thickness is 0.2 to 1.5 mm. When the thickness is in the above range, the moldability can be improved while suppressing heat generation during energization.

(Use)
The copper alloy plate according to the embodiment of the present invention is suitably used for applications of electronic parts such as terminals, connectors, relays, switches, sockets, bus bars, lead frames, heat sinks, etc. used in electric / electronic devices, automobiles, etc. In particular, applications of high-current electronic components such as connectors and terminals for large currents used in electric vehicles, hybrid vehicles, etc., or uses of electronic components for heat dissipation such as liquid crystal frames used in smartphones and tablet PCs Useful for.

  Here, the electronic component for large current is not particularly limited and includes those generally used for large current. For example, it is 10 amperes or more, more typically 30 amperes or more, and more typically 50 amperes or more. An electronic component through which a current flows is shown. Some connectors for electric vehicles and hybrid vehicles carry a current of 100 amperes or more.

(Production method)
In a general manufacturing process of a Corson alloy, first, raw materials such as electrolytic copper, Ni, Co, and Si are melted in a melting furnace to obtain a molten metal having a desired composition. Then, this molten metal is cast into an ingot. Then, it finishes in desired thickness and a characteristic in order of a hot rolling, cold rolling, solution treatment, an aging treatment, final cold rolling, and stress relief annealing. After the heat treatment, surface pickling, polishing, or the like may be performed in order to remove the surface oxide film generated during the heat treatment. In order to increase the strength, cold rolling may be performed between the solution treatment and aging.

The means for adjusting the spring limit value and the I ₍₁₁₁₎ / I ₍₃₁₁₎ value to the above range is not limited to a specific method, but for example, it is possible by controlling the conditions for stress relief annealing as follows. Become.

  The strain relief annealing of the present invention is performed using a continuous annealing furnace. In the case of a batch furnace, since the material is heated in a state of being wound in a coil shape, the material is deformed during the heating, and the material is warped. Therefore, the batch furnace is not suitable for the strain relief annealing of the present invention.

In the continuous annealing furnace, the furnace temperature is set to 300 to 700 ° C., the heating time is appropriately adjusted in the range of 5 seconds to 10 minutes, and the 0.2% proof stress (σ _y ) after the stress relief annealing is set to be before the stress relief annealing. The 0.2% proof stress (σ _y0 ) is adjusted to a value 10 to 50 MPa lower, preferably 15 to 45 MPa lower. Thereby, Kb which was low in the final cold rolling is sufficiently increased. If (σ _y0 −σ _y ) is too small or too large, Kb does not rise sufficiently and it becomes difficult to obtain the relationship of Kb ≧ (σ _y −100).

In the strain relief annealing, the tension applied to the material in the continuous annealing furnace is adjusted to 1 to 5 MPa, more preferably 1 to 4 MPa. If the tension is too large, it becomes difficult to adjust I ₍₁₁₁₎ / I ₍₃₁₁₎ to 5.0 or less. Further, the increase in Kb tends to be insufficient. On the other hand, if the tension is too small, the material in the passing plate of the annealing furnace may come into contact with the furnace wall, and the surface or edge of the material may be damaged.

Next, in the present invention, in order to obtain a crystal orientation of I ₍₂₀₀₎ / I _{0 (200)} ≧ 1.0, a heat treatment (hereinafter also referred to as pre-annealing) and a relatively low workability are performed before the solution treatment. Cold rolling (hereinafter also referred to as light rolling) may be performed.

  The preliminary annealing is performed for the purpose of partially generating recrystallized grains in a rolled structure formed by cold rolling after hot rolling. There is an optimum value for the ratio of recrystallized grains in the rolled structure, and the above-mentioned crystal orientation cannot be obtained if the amount is too small or too large. The optimum proportion of recrystallized grains can be obtained by adjusting the pre-annealing conditions so that the softening degree S defined below is 0.2 to 0.8, more preferably 0.3 to 0.7.

  FIG. 1 illustrates the relationship between the annealing temperature and the tensile strength when the alloy according to the present invention is annealed at various temperatures. A sample with a thermocouple attached was inserted into a 1000 ° C. tubular furnace, and when the sample temperature measured by the thermocouple reached a predetermined temperature, the sample was taken out of the furnace, cooled with water, and the tensile strength was measured. is there. Recrystallization proceeds when the sample arrival temperature is 500 to 700 ° C., and the tensile strength is drastically decreased. The gradual decrease in tensile strength on the high temperature side is due to the growth of recrystallized grains.

The softening degree S in the pre-annealing is defined by the following equation.
S = (σ ₀ −σ) / (σ ₀ −σ ₉₅₀ )
Here, σ ₀ is the tensile strength before annealing, and σ and σ ₉₅₀ are the tensile strength after preliminary annealing and after annealing at 950 ° C., respectively. The temperature of 950 ° C. is adopted as a reference temperature for knowing the tensile strength after recrystallization because the alloy according to the present invention is stably completely recrystallized when annealed at 950 ° C.

When the softening degree is out of the range of 0.2 to 0.8, I ₍₂₀₀₎ / I _{0 (200)} is less than 1.0 on the surface of the copper alloy plate. The temperature and time of the pre-annealing are not particularly limited, and it is important to adjust the softening degree S to the above range. Generally, when a continuous annealing furnace is used, the furnace temperature ranges from 400 to 750 ° C. for 5 seconds to 10 minutes, and when a batch annealing furnace is used, the furnace temperature ranges from 350 to 600 ° C. for 30 minutes to 20 hours. Done in

The pre-annealing conditions can be set by the following procedure.
(1) Measure the tensile strength (σ ₀ ) of the material before pre-annealing. The tensile test may be performed in parallel with the rolling direction (the same applies hereinafter).
(2) The material before preliminary annealing is annealed at 950 ° C. Specifically, the material to which the thermocouple is attached is inserted into a 1000 ° C. tubular furnace, and when the sample temperature measured by the thermocouple reaches 950 ° C., the sample is taken out of the furnace and water-cooled.
(3) Obtain the tensile strength (σ ₉₅₀ ) of the material after annealing at 950 ° C.
(4) For example, when σ ₀ is 800 MPa and σ ₉₅₀ is 300 MPa, the tensile strengths corresponding to the softening degrees of 0.20 and 0.80 are 700 MPa and 400 MPa, respectively.
(5) Pre-annealing conditions are determined so that the tensile strength after annealing is 400 to 700 MPa.

After the preliminary annealing, prior to solution treatment, light rolling with a workability of 3 to 50% is performed. When the degree of processing is out of the range of 3 to 50%, I ₍₂₀₀₎ / I _{0 (200)} becomes less than 1.0. Here, the working degree (r) is a sheet thickness reduction rate before and after the rolling process, and r (%) = (t ₀ −t) / t ₀ × 100 (t ₀ : sheet thickness before rolling, t: after rolling. Thickness).

Preferred manufacturing methods related to the alloy of the present invention are listed in the order of steps as follows.
(1) Ingot casting (thickness 20 to 300 mm)
(2) Hot rolling (temperature 800 to 1000 ° C., thickness 3 to 20 mm)
(3) Cold rolling (4) Pre-annealing (softening degree: 0.20 to 0.80)
(5) Light rolling (working degree: 3-50%)
(6) Solution treatment (700 to 950 ° C. for 5 to 300 seconds)
(7) Cold rolling (working degree 0-60%)
(8) Aging treatment (2 to 20 hours at 350 to 600 ° C.)
(9) Final cold rolling (working degree: 3-80%)
(10) Strain relief annealing (at 300 to 700 ° C. for 5 seconds to 10 minutes, tension: 1 to 5 MPa, 0.2% yield strength reduction: 10 to 50 MPa)

  For the steps (2), (6) and (8), general production conditions for the Corson alloy may be selected.

  The final cold rolling (9) is indispensable for increasing the strength. When the degree of work is less than 3%, it is difficult to adjust the 0.2% proof stress to 500 MPa or more, and when it exceeds 80%, forming is performed. Workability is significantly reduced. Further, the cold rolling (7) is arbitrarily performed for increasing the strength, and the 0.2% proof stress increases as the workability increases, but the forming workability decreases.

  Examples of the present invention will be described below together with comparative examples, but these examples are provided for better understanding of the present invention and its advantages, and are not intended to limit the invention.

After adding the alloy element to the molten copper, it was cast into an ingot having a thickness of 200 mm. The ingot was heated at 950 ° C. for 3 hours and formed into a plate having a thickness of 15 mm by hot rolling. Thereafter, processing and heat treatment were performed in the following order.
(1) Cold rolling (2) Pre-annealing: A continuous annealing furnace was used, the heating temperature was 30 seconds, the furnace temperature was adjusted between 500-750 ° C., and the softening degree was changed variously. In some cases, no pre-annealing was performed.
(3) Light rolling: The degree of processing was changed.
(4) Solution treatment: Using a continuous annealing furnace, the furnace temperature was set to 800 ° C., and the heating time was adjusted between 1 second and 10 minutes so that the crystal grain size after solution treatment was 5 to 20 μm. .
(5) Aging treatment: Using a batch furnace, the heating time was 5 hours, and the furnace temperature was adjusted between 350 and 600 ° C. so that the tensile strength was maximized.
(6) Final cold rolling: The degree of processing was changed.
(7) Straightening annealing: Using a continuous annealing furnace, adjusting the furnace temperature to 500 ° C. and adjusting the heating time from 1 second to 15 minutes, and variously changing the amount of 0.2% proof stress reduction by straightening annealing. It was. In addition, various tensions were added to the material in the furnace. In some cases, strain relief annealing was not performed.

  The following measurements were made on the material after strain relief annealing (after final cold rolling for those not subjected to strain relief annealing).

(component)
The alloy element concentration was analyzed by ICP-mass spectrometry.

(0.2% yield strength)
A No. 13B test piece specified in JIS Z2241 was taken so that the tensile direction was parallel to the rolling direction, and a tensile test was performed in parallel with the rolling direction in accordance with JIS Z2241, to obtain 0.2% yield strength.

(conductivity)
The test piece was sampled so that the longitudinal direction of the test piece was parallel to the rolling direction, and the conductivity at 20 ° C. was measured by a four-terminal method in accordance with JIS H0505.

(Spring limit value)
A strip-shaped test piece having a width of 10 mm and a length of 100 mm was taken so that the longitudinal direction of the test piece was parallel to the rolling direction, and a spring in a direction parallel to the rolling direction was measured by a moment type test specified in JIS H3130. The limit value was measured.

(Product X-ray diffraction)
The X-ray diffraction integrated intensity of the (111) plane, (311) plane, and (200) plane was measured in the thickness direction with respect to the material surface. Furthermore, the X-ray diffraction integrated intensity of the (200) plane was measured for copper powder (manufactured by Kanto Chemical Co., Inc., copper (powder), 2N5,> 99.5%, 325 mesh). RINT 2500 manufactured by Rigaku Corporation was used as the X-ray diffractometer, and measurement was performed with a Cu tube bulb at a tube voltage of 25 kV and a tube current of 20 mA.

(Stress relaxation rate)
A strip-shaped test piece having a width of 10 mm and a length of 100 mm was collected so that the longitudinal direction of the test piece was parallel to the rolling direction. As shown in FIG. 2, with the position of l = 50 mm as the working point, the test piece was given a deflection of y ₀ and a stress (s) corresponding to 80% of the 0.2% proof stress in the rolling direction was applied. y ₀ was determined by the following equation.
y ₀ = (2/3) · l ² · s / (E · t)
Here, E is the Young's modulus in the rolling direction, and t is the thickness of the sample. After unloading at 150 ° C. for 3000 hours, the amount of permanent deformation (height) y is measured as shown in FIG. 3, and the stress relaxation rate {[y (mm) / y ₀ (mm)] × 100 (%) } Was calculated.
When the stress relaxation rate was 30% or less, the stress relaxation resistance was considered good.

(Molding processability)
Using an Eriksen tester, a cup was prepared under the conditions of blank diameter: φ64 mm, punch (punch) diameter: φ33 mm, sheet pressure: 3.0 kN, and lubricant: grease.

Place this cup on the glass plate with the open end side down, read the gap between the recesses between the ears and the glass plate with a microscope, and measure the gap between the four ears generated in the cup. The average value was obtained and used as the ear height.
Further, the appearance of the cup was visually observed to determine the presence or absence of rough skin.

Workability was evaluated according to the following criteria.
◎: Ear height of 0.5 mm or less and no skin roughness ○: Ear height of 0.5 mm or less and slight skin roughness ×: Ear height exceeded 0.5 mm Or skin irritation

  Table 1 shows the product thickness and alloy composition, and Table 2 shows the manufacturing conditions and evaluation results.

In Invention Examples 1 to 40, at least one of Ni and Co is adjusted to a total of 0.8 to 5.0 mass%, Si is adjusted to 0.2 to 1.5 mass%, and the degree of workability in the final cold rolling Was adjusted to 3 to 80%, and the material was passed through a continuous annealing furnace at a tension of 1 to 5 MPa in strain relief annealing to reduce the 0.2% proof stress by 10 to 50 MPa. As a result, a relationship of Kb ≧ (σ _y −100) and a relationship of I ₍₁₁₁₎ / I ₍₃₁₁₎ ≦ 5.0 were obtained, and the stress relaxation rate was 30% or less. In addition, a conductivity of 30% IACS or higher and a 0.2% proof stress of 500 MPa or higher were also obtained.

In the case of Invention Examples 1 to 31 in which pre-annealing with a softening degree of 0.2 to 0.8 and light rolling with a working degree of 3 to 50% were performed, I ₍₂₀₀₎ / I _{0 (200)} was 1.0 or more. Became. In Invention Examples 1 to 23 where I ₍₂₀₀₎ / I _{0 (200)} is 2.0 or more, the evaluation of molding processability is ◎, and I ₍₂₀₀₎ / I _{0 (200)} is 1.0 or more. In the inventive examples 23 to 30 of less than 0, the evaluation of the molding processability was “good”.

On the other hand, since Inventive Examples 32 to 36 were not pre-annealed and light-rolled, Inventive Examples 37 and 38 were out of the range of 0.2 to 0.8 in the pre-annealing, and Inventive Examples 39 and 40 were light. Since the rolling workability was out of the range of 3 to 50%, I ₍₂₀₀₎ / I _{0 (200)} was less than 1.0, and the evaluation of forming workability was x.

Comparative Examples 1 and 2 were not subjected to strain relief annealing, (σ _y −Kb) exceeded 100, I ₍₁₁₁₎ / I ₍₃₁₁₎ also exceeded 5.0, and the stress relaxation rate was 30%. Exceeded.

In Comparative Examples 3 to 7, the amount of decrease in 0.2% yield strength in strain relief annealing was excessively small, and in Comparative Examples 8 and 9, the amount of decrease in 0.2% yield strength in strain relief annealing was excessive. Therefore, (σ _y −Kb) exceeded 100, and the stress relaxation rate exceeded 30%.

In Comparative Examples 10 to 15, since the material tension in the furnace exceeded 5 MPa, I ₍₁₁₁₎ / I ₍₃₁₁₎ exceeded 5.0, and in Comparative Examples 10 and 11 where the tension was particularly high, (σ _y −Kb ) Also exceeded 100. These stress relaxation rates exceeded 30%.

  In Comparative Example 16, the degree of work in final cold rolling was less than 3%, so the 0.2% yield strength after strain relief annealing was less than 500 MPa.

Claims (5)

One or more of Ni and Co are added in a total amount of 0.8 to 5.0 mass%, Si is contained in an amount of 0.2 to 1.5 mass%, the balance is made of copper and inevitable impurities, % Proof stress σ _y and electrical conductivity of 30% IACS or more, and the relationship between spring limit value Kb (MPa) and 0.2% proof stress σ _y (MPa) is given by Kb ≧ (σ _y −100) When the integrated diffraction intensity of the (hkl) plane obtained in the thickness direction on the surface using the X-ray diffraction method is I _(hkl) , I ₍₁₁₁₎ / I ₍₃₁₁₎ is 5.0 or less. Features copper alloy sheet. It is characterized in that I ₍₂₀₀₎ / I _{0 (200)} ≧ 1.0 when the diffraction integrated intensity of the (hkl) plane obtained for copper powder using X-ray diffraction is I _{0 (hkl).} The copper alloy sheet according to claim 1.   3. The content of one or more of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, B, and Ag is 3.0% by mass or less in total amount. Copper alloy plate.   The electronic component for large currents using the copper alloy plate of any one of Claims 1-3.   The electronic component for thermal radiation using the copper alloy plate of any one of Claims 1-3.

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