JP6207539B2 - Copper alloy strip, and electronic component for high current and heat dissipation provided with the same - Google Patents

Description

  The present invention relates to a copper alloy strip, in particular, excellent in heat dissipation, conductivity, strength and bending workability, and used for electronic parts such as terminals, connectors, relays, switches, sockets, bus bars, lead frames, particularly smartphones and The present invention relates to a copper alloy strip suitable for heat-dissipating parts used in personal computers and the like and high-current parts used in electric vehicles and hybrid vehicles.

To dissipate the heat generated by parts and devices for obtaining electrical connections such as terminals, connectors, switches, sockets, relays, busbars, lead frames, etc. in electrical and electronic devices such as smartphones, tablet PCs and personal computers Parts are incorporated.
In recent years, with the miniaturization of smartphones, tablet PCs, and personal computers, heat storage tends to increase when power is supplied to liquid crystal components or IC chips in electric / electronic devices. When the heat storage is large, thermal damage to the IC chip and the substrate is large, and the heat dissipation of the heat dissipation component is a problem.

Conventionally, austenitic stainless steel (for example, SUS304 specified in the section of JIS G 4304 “Hot-rolled stainless steel sheet and steel strip”) and pure heat-dissipating parts in electric / electronic devices such as smartphones, tablet PCs and personal computers are used. Aluminum and the like have been mainly used. For example, a heat-dissipating component (liquid crystal frame) attached to the liquid crystal of a smartphone or tablet PC is required to have strength as a structure and bending workability necessary for fixing to a liquid crystal in addition to high heat dissipation.
Austenitic stainless steel (SUS304) has good bendability, but has low thermal conductivity, and an expensive thermal conductive sheet or the like is used in combination to compensate for it. Therefore, the unit price of the heat dissipating component is increased. On the other hand, pure aluminum and aluminum alloys have good bendability, but lack thermal conductivity and strength as a structure.
Further, in current-carrying parts such as terminals and connectors, 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 particular, electronic components used in fast-growing electric vehicles and hybrid vehicles include components such as a battery connector that allow a very high current to flow, and heat generation of the copper alloy during energization is a problem. Therefore, the current-carrying material is required to have excellent electrical conductivity so that the amount of heat generated is reduced. In addition, strength (particularly high 0.2% proof stress) and excellent bending work are required so that the parts can be made smaller and more functional. Sex is required.

  It is known that thermal conductivity and electrical conductivity are in a proportional relationship, and as an alloy having relatively high electrical conductivity and strength to meet the above requirements, a material obtained by adding Zr, Cr, Ti to Cu is known. Yes. For example, 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-0.08 mass% Fe-0.06 mass% Si-residual Cu), etc. The alloy is registered in CDA (Copper Development Association).

  A certain degree of strength is required for the heat dissipation component and the copper alloy for electronic materials. For example, Cu-Zr alloys such as C15100 among the above alloys may have insufficient strength.

  On the other hand, Cu—Cr—Zr alloys such as C18140 generally have a 0.2% yield strength better than C15100, but it is very difficult to dissolve Cr in the Cu alloy. Therefore, in recent years, inventions for improving the strength, electrical conductivity, and bending workability of Cu-Zr alloys, which are relatively difficult to manufacture, have been made.

  In patent document 1, it is a copper alloy containing Zr in the range of 0.05% to 0.3% by weight ratio, and after the hot rolling, the first cold rolling, the first heat treatment, the second cold rolling, the tension A copper alloy having a good balance of strength, conductivity, and bending workability is disclosed by performing the second heat treatment while adding.

  In Patent Document 2, a copper alloy containing Zr in a range of 0.01 mass% to 0.5 mass%, the orientation distribution density of the Brass orientation in the texture is 20 or less, and the Brass orientation, the S orientation, and the Copper orientation. A copper alloy having a strength of 10 to 50 and a good bending workability is disclosed.

In Patent Document 3, an average of KAM values measured by an EBSD method using a scanning electron microscope with a backscattered electron diffraction image system is a copper alloy containing Zr in a range of 0.05% to 0.2% by weight. Is 1.5 to 1.8 °, R / t is 0.1 to 0.6 and R / t is 0.1 to 0.6, where R is the minimum bend radius at which no cracking occurs in the W bending test, and t is the plate thickness. A copper alloy having excellent strength, springiness and bending workability such as 420 to 520 N / mm ² is disclosed.

  Patent Document 4 contains 0.05 to 1.0 mass% in total of at least one of Cr, Zr, and Ti in a weight ratio, and in the crystal orientation analysis in EBSD measurement, the area ratio of Cube orientation {001} <001> is It discloses a copper alloy that achieves strength, bending workability, and low Young's modulus (longitudinal elastic modulus and deflection coefficient) by having a Vickers hardness of 120 or more and 5% or more and 70% or less.

JP 2010-244852 A JP 2010-242177 A JP 2012-172168 A Japanese Patent No. 5170916

  However, the inventions described in Patent Documents 1 to 4 have some mechanical strength and good bending workability, but the strength and bending workability required for copper alloys such as recent electronic materials. Was not enough. Specifically, in the examples of the invention described in Patent Documents 1 to 3, the tensile strength of the Cu—Zr alloy is 457 to 560 MPa, and in the example described in Patent Document 4, the 0.2% proof stress of the Cu—Zr alloy. Is 425 MPa, and the tensile strength and the 0.2% proof stress may be insufficient.

  Further, although patent documents focus on improving the tensile strength, actual electronic parts often require a high 0.2% proof stress. However, the Cu-Zr alloy has a problem that even if the tensile strength is improved by work hardening, the 0.2% proof stress is not increased beyond a certain level (work hardening is saturated). In addition, since Cu—Zr-based copper alloys are small in precipitation hardening due to aging and work hardening due to rolling, the measures for improving the strength in the patent document mainly involve control of crystal orientation.

  Therefore, the purpose is to provide a copper alloy plate having high strength and conductivity and superior bending workability as compared with conventional materials, and a high-current electronic component and a heat-dissipating electronic component including the same. An object of the present invention is to improve the balance of strength (tensile strength and 0.2% proof stress), conductivity and bending workability.

  The present inventor performs the aging treatment of the Cu-Zr-based copper alloy strip twice or more and adjusts the aging temperature, the cold rolling between the aging and the aging, and the conditions of the cold rolling after the last aging. It was found that excellent strength and electrical conductivity and bending workability can be obtained. Based on the above findings, the following invention has been completed.

  The Cu—Zr-based copper alloy strip of the present invention contains 0.04 to 0.5 mass% of Zr, has a tensile strength of 550 MPa or more, and an electrical conductivity of 80% IACS or more.

  Furthermore, the copper alloy strip of the present invention preferably has a ratio of tensile strength (TS) to 0.2% proof stress (YS) such that YS / TS ≧ 0.9.

  Furthermore, it is preferable that the copper alloy strip of the present invention has a 0.2% proof stress of 500 MPa or more after heating at 300 ° C. for 30 minutes.

Furthermore, in the copper alloy strip of the present invention, the X-ray diffraction integral intensity of the {200} plane obtained in the thickness direction on the rolled surface using the X-ray diffraction method is I {200}, and the X-ray diffraction integral of the {111} plane is When the intensity is I {111}, the X-ray diffraction integrated intensity of _the {220} plane is I {220}, and the X-ray diffraction integrated intensity of the {311} plane is I {311}, 0.1 ≦ [ It is desirable that I {200} + I {111} + I {311}] / I {220} ≦ 0.6.

The copper alloy strip of the present invention preferably contains at most 0.1% by mass of at least one element selected from the group consisting of Ag, Ni, Mn, Mg, Zn, Sn, B and Ca.
The high-current electronic component and the heat-dissipating electronic component of the present invention include any one of the above copper alloy strips.

  According to the present invention, it is possible to provide a copper alloy strip having high strength, high conductivity, and excellent bending workability. This copper alloy strip can be suitably used as a material for electronic parts such as terminals, connectors, switches, sockets, relays, bus bars, lead frames, heat sinks, etc. The present invention relates to a copper alloy strip suitable for use in high-current electronic components used in automobiles and hybrid automobiles.

  Hereinafter, embodiments of the present invention will be described in detail.

(Characteristic)
The copper alloy strip according to an embodiment of the present invention aims to make the conductivity of the copper alloy strip 80% IACS or more and the tensile strength 550 MPa or more. If the electrical conductivity is 80% IACS or higher, the thermal conductivity is good, and there is no problem as a material for electronic components for large currents and heat dissipation components. Moreover, if tensile strength is 550 MPa or more, it has the intensity | strength required as a structural material. If the 0.2% proof stress / tensile strength is 0.9 or more, it has spring characteristics necessary for electronic parts such as connectors, switches, sockets, and relay materials. If the 0.2% yield strength after heating at 300 ° C. for 30 minutes is 500 MPa or more, it has heat resistance as an electronic component for large current and a heat dissipation component. Good bending workability when the X-ray diffraction integrated intensity using the X-ray diffraction method is in the range of 0.1 ≦ [I {200} + I {111} + I {311}] / I {220} ≦ 0.6. It can be said that it has.
The copper alloy strip of the present invention having the above characteristics is suitable for use in electronic components for heat dissipation and high-current electronic components.

(Alloy component concentration)
The Cu—Zr alloy strip according to the embodiment of the present invention contains 0.040 to 0.50 mass% of Zr, and the total content of Zr is preferably 0.050 to 0.30. % By mass, more preferably 0.050 to 0.20% by mass. If the total of Zr is too small, it will be difficult to obtain a tensile strength of 550 MPa or more. If the Zr concentration becomes too high, it becomes difficult to produce an alloy due to hot rolling cracks and the like.

  In order to improve strength and heat resistance, the Cu—Zr alloy can contain one or more of Ag, Sn, Zn, Mg, Mn, B, and Ca. However, if the addition amount is too large, the electrical conductivity may be lowered to be less than 80% IACS, or the manufacturability of the alloy may be deteriorated. .

(Thickness)
The thickness of the product, that is, the plate thickness (t) is preferably 0.05 to 2.0 mm. If the thickness is too small, sufficient heat dissipation cannot be obtained, which is unsuitable as a material for heat dissipation electronic components. On the other hand, if the thickness is too large, bending and drawing are difficult. From such a viewpoint, a more preferable thickness is 0.08 to 1.5 mm. When the thickness is in the above range, it is possible to improve the bending workability while suppressing heat storage.

(conductivity)
In the present invention, the conductivity measured in accordance with JIS H0505 is 80% IACS or higher. If the electrical conductivity is 80% IACS or higher, the thermal conductivity is good and good heat dissipation can be secured. More preferably, it is 85% IACS or more.

(Tensile strength)
In the present invention, when the tensile strength of the copper alloy strip is 550 MPa or more, it can be said that the copper alloy strip has the necessary strength as a material for the structural material. More preferably, it is 570 MPa or more.

(0.2% yield strength)
In the present invention, the 0.2% proof stress / tensile strength (YS / TS) of the copper alloy strip is 0.9 or more. According to this, the copper alloy strip has the spring property required for the connector, switch, and relay material. It can be said that it has.

(Heat-resistant)
In the present invention, 0.2% yield strength after heating at 300 ° C. for 30 minutes ≧ 500 MPa, and according to this, it can be said that it has heat resistance as a high-current electronic component and a heat dissipation component.

(Bending workability)
Evaluation of the bending workability of the present invention is performed by a W bending test (JIS-H3130) using a strip-shaped test piece having a width of 10 mm and a length of 30 mm. The specimen collection direction is a rolling parallel direction (GW) and a rolling perpendicular direction (BW), and evaluation is performed by a ratio MBR / t of a minimum bending radius MBR (Minimum Bend Radius) and a thickness t where no crack is generated. The ratio (MBR / t) of the minimum bending radius (MBR) is preferably 2.0 or less from the viewpoint of ensuring good bendability. A more preferable range of MBR / t is 1.8 or less.

(Crystal orientation)
The X-ray diffraction integrated intensity of the {200} plane obtained in the thickness direction on the surface of the rolled surface using the X-ray diffraction method is I {200}, the X-ray diffraction integrated intensity of the {111} plane is I {111} _, When the {220} plane X-ray diffraction integral intensity is I {220} and the {311} plane X-ray diffraction integral intensity is I {311}, 0.1 ≦ [I {200} + I {111} When + I {311}] / I {220} ≦ 0.6 (that is, 0.1 or more and 0.6 or less), the bending workability is improved. A more preferable range is 0.25 or more and 0.55 or less. On the other hand _, when it is out of _the above range, the bending workability is inferior. The pure copper powder standard sample is defined as a copper powder of 99.5% purity of 325 mesh (JIS Z8801).

  Hereinafter, an example of a suitable method for producing a copper alloy strip according to the present invention will be described.

  Electro copper or the like is melted as a pure copper raw material, Zr and other alloy elements are added as required, and cast into an ingot having a thickness of about 30 to 300 mm. After making this ingot 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 aging treatment at least twice are repeated, and the final cold rolling is finished to a predetermined product thickness, In some cases, strain relief annealing is applied at the end. The strain relief annealing need not be particularly performed.

The aging treatment is performed twice or more at a temperature of 300 ° C. to 400 ° C. for 1 to 30 hours. Preferably it is 340-390 degreeC, More preferably, it is 350-390 degreeC.
By annealing under an appropriate condition such that the rolled structure does not recrystallize, work hardening by subsequent rolling increases, and a tensile strength of 550 MPa or more is obtained. If the aging temperature is higher than 400 ° C., a strength of 550 MPa or more cannot be obtained. On the other hand, when the aging temperature is lower than 300 ° C., a conductivity of 80% IACS or higher cannot be obtained.
The final aging temperature is adjusted to a range of ± 25 ° C. with respect to the aging temperature immediately before the last, so that the crystal orientation is 0.1 ≦ [I {200} + I {111} + I {311}] / I Bending workability is improved in the range of {220} ≦ 0.6.
Furthermore, when the last aging temperature is 0 to 25 ° C. lower than the last aging temperature, the 0.2% proof stress after heating at 300 ° C. for 30 minutes becomes 500 MPa or more. On the other hand, when the last aging temperature is high, the 0.2% proof stress after heating at 300 ° C. for 30 minutes becomes 500 MPa or less, and the balance of strength, conductivity and bending workability is excellent, but there is room for improvement from the viewpoint of heat resistance. Remains.
The tensile strength, electrical conductivity, and 0.2% proof stress are the various conditions of processing, for example, the degree of processing during the aging treatment, the temperature of the first aging treatment, the degree of processing of the final cold rolling, and the concentration of Zr By appropriately adjusting the additive elements and the like, it can be made better.

  YS / TS ≧ 0.9 can be obtained by adjusting the degree of cold rolling between aging to 60% or more. A more preferable degree of processing is 75% or more. If the degree of cold rolling between aging is less than 60%, YS / TS ≧ 0.9 cannot be obtained.

  As long as the aging conditions and the cold rolling workability between aging are adjusted, there is no problem even if aging is performed any number of times.

  The cold rolling degree after the last aging is 50% to 80%. Preferably it is 60 to 75%, more preferably 60 to 70%. If it is less than 50%, a tensile strength of 550 MPa cannot be obtained, and if it is 80% or more, the Cu—Zr compound precipitated by aging is re-dissolved in the parent phase by rolling, and the electrical conductivity is reduced to less than 80% IACS.

  When strain relief annealing is performed, a continuous annealing furnace is used. The furnace temperature is set to 300 to 700 ° C., preferably 350 to 650 ° C., and is set in the range of 5 seconds to 10 minutes. It is not always necessary to carry out strain relief annealing.

One embodiment of the present invention is characterized in that the tensile strength of Cu-Zr alloy strip is ≧ 550 MPa and the conductivity is ≧ 80% IACS, YS / TS ≧ 0.9, 0.2 after heating at 300 ° C. × 30 min. % Proof stress ≧ 500 MPa and 0.1 ≦ [I {200} + I {111} + I {311}] / I {220} ≦ 0.6 to give strength, conductivity, and bending Improves sex. The manufacturing conditions for that purpose are summarized and shown.
(1) For tensile strength ≧ 550 MPa,
a. Adjust the aging temperature below 400 ° C.
b. Adjust the finish rolling degree to 50% or more.
(2) For conductivity ≥80% IACS,
a. Adjust the aging temperature to 300 ° C or higher.
b. Adjust the finish rolling degree to 80% or less.
(3) For YS / TS ≧ 0.9,
a. Adjust the cold rolling degree between aging to 60% or more.
(4) For 0.2% proof stress ≧ 500 MPa after heating at 300 ° C. for 30 minutes,
a. The last aging temperature is adjusted to 0 to 25 ° C. lower than the last aging temperature.
(5) For 0.1 ≦ [I {200} + I {111} + I {311}] / I {220} ≦ 0.6,
a. The last aging temperature is adjusted to a range of ± 25 ° C. with respect to the last aging temperature.

  Copper alloy strips manufactured as described above are processed into copper strips with various plate thicknesses. For example, high-current electronic components and heat-dissipating electrons in electrical and electronic devices such as smartphones, tablet PCs, and personal computers. It can be used for parts and the like.

  Examples of the present invention are shown below, but these examples are provided for better understanding of the present invention and its advantages, and are not intended to limit the invention. In the following examples, the aging frequency is 2 times, but there is no problem even if the aging frequency is 3 or more.

  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 hot-rolled at 950 ° C. to obtain a plate having a thickness of 15 mm. After grinding and removing the oxidized scale on the surface of the hot rolled sheet with a grinder, aging 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.

  In the first aging, a batch furnace was used, and heat treatment was performed at a furnace temperature in the range of 200 to 500 ° C. for 1 to 30 hours.

  In the cold rolling after aging, the total workability was controlled.

  The final aging was also performed using a batch furnace, and heat treatment was performed at a furnace temperature in the range of 200 to 500 ° C. for 1 to 30 hours. Various conditions were changed with respect to the first aging temperature.

  In the final cold rolling, the total working degree was controlled.

  In the strain relief annealing, the furnace temperature was 500 ° C. and the heating time was adjusted between 1 second and 15 minutes. For some materials, strain relief annealing was omitted.

  The production conditions of the examples are shown in Table 1 for each invention example and comparative example. 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 the final cold rolling or strain relief annealing was analyzed by ICP-mass spectrometry. In addition, the element analysis value in a table | surface does not fill in the element lower than 10 ppm.

(Tensile strength and 0.2% yield strength)
For the material after the final cold rolling and after strain relief annealing, the 13B test piece specified in JIS Z2241 was taken so that the tensile direction was parallel to the rolling direction, and parallel to the rolling direction in accordance with JIS Z2241. A tensile test was performed to determine tensile strength (TS) and 0.2% yield strength (YS).

(Heat-resistant)
After holding the material in a furnace set at 300 ° C. for 30 minutes, the sample taken out and air-cooled was measured for 0.2% yield strength in the same manner as described in the section of “Tensile strength and 0.2% yield strength”.

(Elongation)
From the material after the final cold rolling or strain relief annealing, a No. 13B test piece specified in JIS Z2241 was sampled so that the tensile direction was parallel to the rolling direction, and the elongation was measured at a distance between the gauge points of 50 mm.

(conductivity)
From the material after the final cold rolling or strain relief annealing, a test piece is taken so that the longitudinal direction of the test piece is parallel to the rolling direction, and the conductivity at 20 ° C. is measured by a four-terminal method in accordance with JIS H0505. Was measured.

(Crystal orientation)
The X-ray diffraction intensity I of {200}, {111}, {311} and {220} planes was measured on the surface of the rolled surface of the material after the final cold rolling or strain relief annealing. 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.

(MBR / t)
In accordance with JIS H3130, a W-shaped test is performed in each of the GW (Goodway) direction in which the bending axis is perpendicular to the rolling direction and the BW (Badway) direction in which the bending axis is the same as the rolling direction. The bending radius was changed using the mold of the mold, and the ratio (MBR / t) of the minimum bending radius (MBR) and thickness (t) at which no crack occurred was obtained.

As can be seen from Table 1, Invention Examples 1 to 20 contain Zr in a total amount of 0.04 to 0.50 mass%, and the first aging is performed at 300 to 400 ° C., followed by cooling. The cold rolling degree is adjusted to 60% or more, the final aging thereafter is performed at 300 to 400 ° C., the final cold rolling degree is adjusted to 50 to 80%, and finally, stress relief annealing is performed ( Invention Example 12 was omitted). As a result, the copper alloy sheets of Invention Examples 1 to 20 were able to achieve tensile strength ≧ 550 MPa, 0.2% proof stress / tensile strength ≧ 0.9, and electrical conductivity ≧ 80% IACS.
In addition, when the temperature difference between the first aging and the final aging was within ± 25 ° C., the bending workability was improved, and when the first aging temperature was lower than the final aging temperature, the heat resistance was improved. From this point of view, when compared with other inventive examples, Invention Example 5 has poor heat resistance because the first aging temperature was lower than the final aging temperature, and Invention Example 7 had a temperature difference of 25 ° C. between the first and final aging. As described above, heat resistance and bending workability were poor.

On the other hand, Comparative Examples 1 and 2 had an aging temperature outside the range of 300 to 400 ° C., Comparative Example 1 having a low aging temperature had low electrical conductivity, and Comparative Example 2 having a high aging temperature had low tensile strength.
In Comparative Example 3, the degree of cold rolling during aging was low, and the ratio of 0.2% proof stress / tensile strength was less than 0.9.
Comparative Examples 5 and 6 have a final cold rolling workability outside the range of 50 to 80%, Comparative Example 5 with low workability has low tensile strength, and Comparative Example 6 with high workability has low conductivity. It was.
Comparative Examples 7 and 8 are materials produced by a single aging treatment, and it was difficult to achieve a balance between tensile strength, a ratio of 0.2% proof stress / tensile strength, or a balance of conductivity.
In Comparative Example 9, the Zr concentration was low and the tensile strength was low.
In Comparative Example 10, since the concentration of the additive element was 0.1% by mass or more, the conductivity was low.
Comparative example 11 is a copper alloy produced by the same manufacturing method as Example 1 of patent document 1 (Unexamined-Japanese-Patent No. 2010-248592). The ratio of tensile strength and 0.2% proof stress / tensile strength was low.
Comparative Examples 12 and 13 are copper alloys produced by the same manufacturing method as Example 1 and Example 12 of Patent Document 2 (Japanese Patent Laid-Open No. 2010-242177), respectively. In the Cu-Zr alloy of Comparative Example 12, both the tensile strength and the ratio of 0.2% proof stress / tensile strength were low. On the other hand, the tensile strength ≧ 550 MPa and the electrical conductivity ≧ 80% IACS were satisfied by adding the additive element as in Comparative Example 13, but the 0.2% proof stress was low, and the ratio of 0.2% proof strength / tensile strength. Was low.
Comparative Example 14 is Example 5 of Patent Document 3 (Japanese Patent Laid-Open No. 2012-172168), Comparative Example 15 is Invention Example 1-1 of Patent Document 4 (Patent No. 5170916), and copper produced by the same manufacturing method. Although it was an alloy, the 0.2% yield strength was low, and the ratio of 0.2% yield strength / tensile strength was low.

  From the above results, according to the present invention, there are provided a copper alloy plate having high strength, conductivity and bending workability, a high-current electronic component including the same, a heat-dissipating electronic component, and a method for producing the copper alloy plate Obviously you can.

Claims (5)

A copper alloy strip containing 0.04 to 0.5% by mass of Zr, with the balance being Cu and inevitable impurities, with a tensile strength of 550 MPa or more and 0.2% proof stress / tensile strength ≧ 0 .9 and the electrical conductivity satisfies 80% IACS or more,
The X-ray diffraction intensity from the {200} plane on the surface of the rolled surface is I {200}, the X-ray diffraction intensity from the {111} plane is I {111}, and the X-ray diffraction integrated intensity of the {311} plane is When I {311} and the X-ray diffraction intensity from the {220} plane is I {220}, 0.1 ≦ [I {200} + I {111} + I {311}] / I {220} ≦ 0 Copper alloy strip satisfying .6.   The copper alloy strip according to claim 1, wherein 0.2% yield strength after heating at 300 ° C. for 30 minutes ≧ 500 MPa is satisfied.   The copper alloy strip according to claim 1 or 2, containing at most 0.1 mass% of at least one element selected from the group consisting of Ag, Ni, Mn, Mg, Zn, Sn, B, and Ca.   The electronic component for large currents provided with the copper alloy strip of any one of Claims 1-3.   A heat dissipating electronic component comprising the copper alloy strip according to any one of claims 1 to 3.