JP5536258B1 - Copper alloy sheet with excellent conductivity and stress relaxation properties - Google Patents

Abstract

A copper alloy plate having high strength, high conductivity, and excellent stress relaxation characteristics, and a high-current electronic component and a heat dissipation electronic component using the copper alloy plate are provided.
The present invention contains one or two of Zr and Ti in a total amount of 0.01 to 0.50% by mass, the balance is made of copper and its inevitable impurities, and the tensile strength is 350 MPa or more. And a residual stress generated in a direction parallel to the rolling direction with respect to the (113) plane obtained by the X-ray diffraction method is 200 MPa or less.
[Selection figure] 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, etc. 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 components to transmit electricity or heat, such as terminals, connectors, switches, sockets, relays, bus bars, lead frames, heat sinks, etc. 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 plate 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 sheet is required to be excellent in conductivity so that the amount of heat generation is reduced, and is also required to be excellent in stress relaxation characteristics 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 stress relaxation characteristics are enhanced, 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. The effect of can be expected. For this reason, it is desired that the copper alloy plate for heat dissipation also has excellent stress relaxation characteristics.

  It is known that when Zr or Ti is added to Cu, the stress relaxation characteristics are improved (see, for example, Patent Document 1). Examples of materials having high electrical conductivity and relatively high strength and good stress relaxation characteristics include C15100 (0.1 mass% Zr-residual Cu), C15150 (0.02 mass% Zr-residual Cu), C18140 (0 .1 mass% Zr-0.3 mass% Cr-0.02 mass% Si-residual Cu), C18145 (0.1 mass% Zr-0.2 mass% Cr-0.2 mass% Zn-residual Cu) C18070 (0.1 mass% Ti-0.3 mass% Cr-0.02 mass% Si-residual Cu), C18080 (0.06 mass% Ti-0.5 mass% Cr-0.1 mass% Ag) Alloys such as -0.08 mass% Fe-0.06 mass% Si-residual Cu) are registered in CDA (Copper Development Association).

JP 2011-1117055 A

  However, although a copper alloy obtained by adding Zr or Ti to Cu (hereinafter referred to as a Cu-Zr-Ti alloy) has relatively good stress relaxation characteristics, the level of the stress relaxation characteristics is a large current. It was not always sufficient as a use of a component that flows heat or a use of a component that dissipates a large amount of heat. For example, in the copper alloy plate disclosed in Patent Document 1, 0.05 to 0.3% by mass of Zr is added, and Mg, Ti, Zn, Ga, Y, Nb, Mo, Ag, In, and Sn are included. The stress relaxation characteristics are improved by adding one or more of 0.01 to 0.3% by mass and adjusting the crystal grain size after intermediate annealing to 20 to 100 μm. The stress relaxation rate after holding for 1000 hours is at least 17.2%.

  Therefore, the present invention has an object to provide a copper alloy plate having high strength, high conductivity, and excellent stress relaxation characteristics, and an electronic component suitable for large current use or heat radiation use. It is an object of the present invention to provide a Cu—Zr—Ti alloy having improved relaxation characteristics. Furthermore, an object of the present invention is to provide an electronic component suitable for high current use or heat dissipation use.

  As a result of intensive studies, the inventor has adjusted Cu-Zr-Ti alloy having a high strength and high conductivity by adjusting the residual stress on the surface to be within a predetermined range. It has been found that the stress relaxation properties of the alloy are improved.

The present invention completed on the basis of the above knowledge, in one aspect, contains one or two of Zr and Ti in a total of 0.01 to 0.50 mass%, the balance consists of copper and inevitable impurities, The tensile strength is 350 MPa or more, the electrical conductivity is 75% IACS or more , the stress relaxation rate after holding at 150 ° C. for 1000 hours is 15% or less , and the rolling direction with respect to the (113) plane determined by the X-ray diffraction method It is a copper alloy plate whose residual stress generated in the parallel direction is 200 MPa or less.

In another aspect of the present invention, one or two of Zr and Ti are contained in a total amount of 0.01 to 0.50% by mass, and Ag, Fe, Co, Ni, Cr, Mn, Zn, Mg , Si, P, Sn and B are contained in an amount of 1.0% by mass or less, the balance is made of copper and inevitable impurities, the tensile strength is 350 MPa or more, the conductivity is 75% IACS or more , 150 ° C. And a stress relaxation rate after holding for 1000 hours is 15% or less , and the residual stress generated in the direction parallel to the rolling direction with respect to the (113) plane obtained by X-ray diffraction method is 200 MPa or less It is.

  In another embodiment, the copper alloy sheet according to the present invention is a ratio (B / A) of the average crystal grain size A in the thickness direction and the average crystal grain size B in the width direction obtained from the structure of the cross section perpendicular to the rolling direction. ) Is 1.3 or more.

  In yet another embodiment of the copper alloy sheet according to the present invention, the average grain size B in the width direction determined from the cross-sectional structure orthogonal to the rolling direction is 50 μm or less.

  Another aspect of the present invention is an electronic component for large current using the copper alloy plate.

  In another aspect of the present invention, there is provided a heat dissipating electronic component using the copper alloy plate.

  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 an electronic component suitable for large current use or heat radiation use. 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 figure which shows the measurement principle of a residual stress. 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.

Embodiments of the present invention will be described below.
(Target characteristics)
The copper alloy plate according to the embodiment of the present invention has a conductivity of 75% IACS or more and a tensile strength of 350 MPa or more. If the electrical conductivity is 75% IACS or higher, it can be said that the amount of heat generated during energization is equivalent to that of pure copper. Further, if the tensile strength is 350 MPa or more, it can be said that the material has a strength necessary for a material for a component that conducts a large current or a material for a component that dissipates a large amount of heat.

  Regarding the stress relaxation characteristics of the copper alloy plate according to the embodiment of the present invention, the stress relaxation rate of the copper alloy plate when the stress of 80% of 0.2% proof stress is applied and held at 150 ° C. for 1000 hours is 15 % Or less, more preferably 10% or less. The stress relaxation rate of a normal Cu-Zr-Ti alloy is about 25 to 35%, but by making this 15% or less, even if a large current is applied after processing into an electronic component such as a connector, the contact is achieved It is difficult for the contact electric resistance to increase due to the decrease in force, and creep deformation hardly occurs even if heat and external force are applied simultaneously after processing the heat sink.

(Alloy component concentration)
The copper alloy plate according to the embodiment of the present invention contains one or two of Zr and Ti in a total amount of 0.01 to 0.50% by mass, more preferably 0.02 to 0.20% by mass. . When the total of one or two of Zr and Ti is less than 0.01% by mass, it becomes difficult to obtain a tensile strength of 350 MPa or more and a stress relaxation rate of 15% or less. If the total of one or two of Zr and Ti exceeds 0.50% by mass, it becomes difficult to produce an alloy due to hot rolling cracks or the like. When adding Zr, it is preferable to adjust the addition amount to 0.01 to 0.45 mass%, and when adding Ti, the addition amount is adjusted to 0.01 to 0.20 mass%. It is preferable. When the addition amount is less than the lower limit value, it is difficult to obtain the effect of improving the stress relaxation characteristics, and when the addition amount exceeds the upper limit value, conductivity and manufacturability may be deteriorated.

  Cu-Zr-Ti alloy contains at least one of Ag, Fe, Co, Ni, Cr, Mn, Zn, Mg, Si, P, Sn and B in order to improve strength and heat resistance. Can be made. However, if the amount added is too large, the electrical conductivity may be reduced to be less than 75% IACS, or the manufacturability of the alloy may be deteriorated. Therefore, the amount added is preferably 1.0% by mass or less, more preferably Is 0.5 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.

(Residual stress)
The copper alloy plate according to the embodiment of the present invention has a stress relaxation rate of 15% or less by adjusting the residual stress on the product surface to 200 MPa or less, preferably 100 MPa or less. Here, the residual stress of the present invention is determined by measuring the change in (113) plane spacing with respect to the X-ray incident angle using the X-ray diffraction method. As the measurement direction, the residual stress value generated in parallel with the rolling direction is obtained by changing the X-ray incident angle in a plane parallel to the rolling direction and the thickness direction. Although it is possible to measure residual stress values for other crystal planes and directions, the measurement variation is the smallest when measured under these conditions, and the best between residual stress values and stress relaxation A good correlation was obtained. The residual stress of a copper alloy plate is often calculated from the amount of warpage of the plate when one side surface of the plate is etched (Kazuto Sudo: Residual Stress and Distortion, Uchida Otsuru Farm Co., (1988) P.46.), The residual stress value obtained by this etching method was not correlated with stress relaxation.

(Grain shape)
In a cross section orthogonal to the rolling direction of the copper alloy sheet according to the embodiment of the present invention (hereinafter referred to as a cross section perpendicular to rolling), the average crystal grain size A in the thickness direction and the width direction (perpendicular to each of the rolling direction and the thickness direction). (Direction) to the average crystal grain size B (aspect ratio B / A) is preferably 1.3 or more. If the aspect ratio is less than 1.3, the tensile strength may be less than 350 MPa.

  Moreover, it is preferable that the average crystal grain size B of the width direction of the cross section of a copper alloy plate at the right angle of rolling is 50 μm or less. If the B value exceeds 50 μm, the tensile strength may be less than 350 MPa.

(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 is reduced and heat generation during current-carrying increases, so that it is not suitable as a material for a connector or the like through which a large current flows. On the other hand, if the thickness is too thick, bending 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 bending workability 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 current used in electric vehicles, hybrid vehicles, etc., or applications of heat dissipation electronic components such as liquid crystal frames used in smartphones and tablet PCs Useful for.

(Production method)
After dissolving electrolytic copper or the like as a pure copper raw material and reducing the oxygen concentration by carbon deoxidation or the like, one or two of Zr and Ti, and other alloy elements are added as necessary, and the thickness is 30 to 300 mm. Cast into a moderate ingot. After this ingot is made into a plate having a thickness of about 3 to 30 mm by hot rolling at 800 to 1000 ° C., for example, cold rolling and recrystallization annealing are repeated, and finally finished to a predetermined product thickness by cold rolling. Apply strain relief annealing. The residual stress introduced into the material in the final cold rolling is reduced by subsequent strain relief annealing.

  In recrystallization annealing, the rolled structure is recrystallized. Further, by annealing under appropriate conditions, Zr, Ti, etc. are precipitated, and the electrical conductivity of the alloy is increased. In the recrystallization annealing before the final cold rolling, the average crystal grain size after the recrystallization annealing is adjusted to 50 μm or less so that the average crystal grain size in the cross section perpendicular to the rolling of the product is 50 μm or less. For recrystallization annealing before final cold rolling, a batch furnace may be used, or a continuous annealing furnace may be used. In a batch furnace, by appropriately adjusting the heating time in the range of 30 minutes to 30 hours at a furnace temperature of 150 to 750 ° C., and in a continuous annealing furnace, a range of 5 seconds to 15 minutes at a furnace temperature of 450 to 800 ° C. By adjusting the heating time appropriately, the average crystal grain size after the recrystallization annealing can be adjusted to 50 μm or less. Generally, when annealing is performed at a lower temperature for a longer time, higher conductivity can be obtained with the same crystal grain size.

In the final cold rolling, the material is repeatedly passed between a pair of rolling rolls to finish the target plate thickness. The workability of the final cold rolling is 25 to 99%. Here, the working degree r (%) is given by r = (t ₀ −t) / t ₀ × 100 (t ₀ : plate thickness before rolling, t: plate thickness after rolling). When the degree of processing is less than 25%, it becomes difficult to adjust the aspect ratio to 1.3 or more. If the degree of work exceeds 99%, the edges of the rolled material may be broken.

  Further, in the final cold rolling, the residual stress of the copper alloy plate can be adjusted by adjusting the diameter of the rolling roll and the number of plate passes. When rolling is performed using a generally used large-diameter roll, tensile stress remains in the surface portion and compressive stress remains in the central portion in the thickness direction. On the other hand, when rolling is performed at a low workability using a small-diameter roll, compressive stress remains in the surface portion and tensile stress remains in the central portion in the thickness direction. Thus, if rolling is performed with a large-diameter roll and then light-rolling with a small-diameter roll several times, the tensile residual stress accumulated on the surface by the previous rolling is canceled and the residual stress of the copper alloy sheet is reduced. In the present embodiment, the large diameter roll means a roll having a diameter of 150 to 500 mm, and the small diameter roll means a roll having a diameter of 20 to 80 mm.

  Residual stress can be adjusted to 200 MPa or less by performing strain relief annealing under appropriate conditions in addition to the rolling with the small-diameter roll. 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 a continuous annealing furnace, the furnace temperature is 300 to 700 ° C., the heating time is appropriately adjusted in the range of 5 seconds to 10 minutes, and the tensile strength after strain relief annealing is the tensile strength before strain relief annealing (after final rolling). The strength is adjusted to a value 10 to 100 MPa lower, preferably 15 to 50 MPa lower. If the amount of decrease in tensile strength is too small, it is difficult to adjust the residual stress to 200 MPa or less. If the decrease in tensile strength is too large, the tensile strength of the product may be less than 350 MPa.

  Further, after 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 is difficult to adjust the residual stress to 200 MPa or less. 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.

  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. After grinding and removing the oxide scale on the surface of the hot rolled plate with a grinder, annealing and cold rolling were repeated, and the product was finished to a predetermined product thickness by final cold rolling. Finally, strain relief annealing was performed using a continuous annealing furnace.

  For annealing before final cold rolling (final recrystallization annealing), a batch furnace is used, the heating time is 5 hours, the furnace temperature is adjusted in the range of 200 to 700 ° C., and the crystal grain size and conductivity after annealing are adjusted. Changed.

  In the first half of the final cold rolling, a large-diameter roll having a diameter of 200 mm was used, and in the latter half, a small-diameter roll having a diameter of 50 mm was used. In rolling in the latter half of the small-diameter roll, the degree of processing per pass was 3%, and the number of passes was changed in the range of 0-5.

  In strain relief annealing using a continuous annealing furnace, the furnace temperature was 500 ° C., the heating time was adjusted between 1 second and 10 minutes, and the amount of decrease in tensile strength due to the annealing was variously changed. In addition, various tensions were added to the material in the furnace. In some cases, strain relief annealing was not performed.

The following measurement was performed on the material in the process of manufacturing and the material after strain relief annealing.
(component)
The alloy element concentration of the material after strain relief annealing was analyzed by ICP-mass spectrometry.

(Average grain size after recrystallization annealing before final cold rolling)
After rolling the right-angled cross section of the copper alloy plate to a mirror surface by mechanical polishing, crystal grain boundaries were revealed by etching. On this metal structure, the average crystal grain size was determined by measurement according to the cutting method of JIS H 0501 (1999).

(Average grain size and aspect ratio in the width direction after strain relief annealing (product))
After rolling the right-angled cross section of the copper alloy plate to a mirror surface by mechanical polishing, crystal grain boundaries were revealed by etching. On this metal structure, a straight line was drawn in the thickness direction of the cross section perpendicular to the rolling, and the number of crystal grains cut by the straight line was determined. The value obtained by dividing the length of the straight line by the number of crystal grains was defined as the average crystal grain size A in the thickness direction. Similarly, a straight line is drawn in the width direction of the perpendicular cross section of rolling, the number of crystal grains cut by the straight line is obtained, and the value obtained by dividing the length of the straight line by the number of crystal grain sizes is the average crystal grain size B in the width direction. It was. The (B / A) value was taken as the aspect ratio.

(Tensile strength)
For the material after the final cold rolling and strain relief annealing, sample No. 13B specified in JIS Z2241 was taken so that the tensile direction was parallel to the rolling direction, and pulled in parallel with the rolling direction in accordance with JIS Z2241. A test was conducted to determine the tensile strength.

(conductivity)
A test piece was taken from the material after strain relief annealing 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.

(Residual stress)
Residual stress generated in the direction parallel to the rolling direction was determined with respect to the (113) plane of the copper alloy plate by X-ray diffraction. The measurement principle will be described below.
For example, when there is a tensile residual stress as shown in FIG. 1, if the angle Ψ between (a) → (b) → (c), the sample surface normal N and the lattice surface normal N ′ increases, this order The lattice spacing increases. Since the crystal plane spacing is proportional to the magnitude of the stress, when the lattice plane spacing, that is, the diffraction angle (2θ) is measured at each Ψ, the residual stress σ can be obtained by the following equation.

ここで、σは応力、Ｅはヤング率、νはポアソン比、θ₀は標準ブラッグ角である。また、Ｋは材料と測定波長により決定される定数である。２θとｓｉｎ²Ψとの関係を図示して最小二乗法で勾配を求め、これにＫを乗じることで残留応力値が得られる。

Here, σ is stress, E is Young's modulus, ν is Poisson's ratio, and θ ₀ is standard Bragg angle. K is a constant determined by the material and the measurement wavelength. The relationship between 2θ and sin ² Ψ is illustrated, a gradient is obtained by the least square method, and a residual stress value is obtained by multiplying this by K.

(Stress relaxation rate)
A strip-shaped test piece having a width of 10 mm and a length of 100 mm was collected from the material after strain relief annealing 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 after heating at 150 ° C. for 1000 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.

  Table 1 shows the evaluation results. The residual stress value indicates the absolute value of the compressive or tensile residual stress value.

  In the copper alloy plates of Invention Examples 1 to 25, the total concentration of Zr and Ti is adjusted to 0.01 to 0.50 mass%, and the crystal grain size is adjusted to 50 μm or less in the recrystallization annealing before the final cold rolling. In the final cold rolling, the degree of work is set to 25 to 99%, and the sheet passing with a small diameter roll is performed three or more times. In the strain relief annealing, the material is passed through a continuous annealing furnace at a tension of 1 to 5 MPa and the tensile strength is 10 Reduced by ~ 100 MPa.

  As a result, in the copper alloy sheets of Invention Examples 1 to 25, the average crystal grain size in the width direction was 50 μm or less, the aspect ratio was 1.3 or more, and the rolling direction was determined with respect to the (113) plane obtained by the X-ray diffraction method. The residual stress generated in the parallel direction was 200 MPa or less, and a conductivity of 75% IACS or more, a tensile strength of 350 MPa or more, and a stress relaxation rate of 15% or less were obtained.

In Comparative Example 1, the strain relief annealing was not performed, the residual stress exceeded 200 MPa, and the stress relaxation rate exceeded 15%.
In Comparative Examples 2 to 4, although strain relief annealing was performed, the material tension in the furnace exceeded 5 MPa, the residual stress exceeded 200 MPa, and the stress relaxation rate exceeded 15%.
In Comparative Examples 5, 6, 7, and 8, the number of passes through the small diameter roll in the final cold rolling was too small, so the residual stress exceeded 200 MPa and the stress relaxation rate exceeded 15%.
In Comparative Examples 9 and 10, the amount of decrease in tensile strength during strain relief annealing was too small, so the residual stress exceeded 200 MPa and the stress relaxation rate exceeded 15%.

  In Comparative Example 11, the degree of work in final cold rolling was less than 25%, and the aspect ratio was less than 1.3. In Comparative Example 12, the crystal grain size after recrystallization annealing before final cold rolling was 50 μm. Since the average grain size in the width direction after strain relief annealing exceeded 50 μm, the tensile strength after strain relief annealing was less than 350 MPa.

  In Comparative Example 13, since the total concentration of Zr and Ti was less than 0.01% by mass, the tensile strength after strain relief annealing was less than 350 MPa, and the stress relaxation rate exceeded 15%.

Claims (6)

One or two of Zr and Ti are contained in a total of 0.01 to 0.50% by mass, the balance is made of copper and inevitable impurities, the tensile strength is 350 MPa or more, and the conductivity is 75% IACS or more . The stress relaxation rate after holding at 150 ° C. for 1000 hours is 15% or less , and the residual stress generated in the direction parallel to the rolling direction with respect to the (113) plane obtained by the X-ray diffraction method is 200 MPa or less. Copper alloy plate characterized by One or two of Zr and Ti are contained in a total of 0.01 to 0.50% by mass, and further Ag, Fe, Co, Ni, Cr, Mn, Zn, Mg, Si, P, Sn, and B 1.0% by mass or less of at least one of them, the balance being copper and inevitable impurities, tensile strength is 350 MPa or more, conductivity is 75% IACS or more , stress relaxation rate after holding at 150 ° C. for 1000 hours 15% or less , and the residual stress generated in the direction parallel to the rolling direction with respect to the (113) plane obtained by the X-ray diffraction method is 200 MPa or less.   The ratio (B / A) of the average crystal grain size A in the thickness direction and the average crystal grain size B in the width direction obtained from the structure of the cross section orthogonal to the rolling direction is 1.3 or more. Copper alloy plate.   The copper alloy sheet according to any one of claims 1 to 3, wherein an average crystal grain size B in a width direction obtained from a structure of a cross section perpendicular to the rolling direction is 50 µm or less. The electronic component for large currents using the copper alloy plate of any one of Claims 1-4 . The electronic component for thermal radiation using the copper alloy plate of any one of Claims 1-4 .

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