JP2019178398A - Copper alloy for electronic and electric device, copper ally stripe material for electronic and electric device, component for electronic and electric device, terminal, and bus bar - Google Patents

Abstract

An object of the present invention is to provide a copper alloy for electronic and electric equipment which is excellent in conductivity, strength, bending workability, stress relaxation resistance, castability, and punching workability. SOLUTION: A predetermined amount of Mg and P is contained, and the balance is made of Cu and unavoidable impurities. The parent phase is analyzed by the EBSD method with the plane orthogonal to the observation plane as the observation plane. When the other is a random grain boundary, the ratio of all three grain boundaries forming the grain boundary triple point is a special grain boundary is NFJ3, and the two grain boundaries forming the grain boundary triple point are special grain boundaries. Where NFJ2 is the ratio of one of which is a random grain boundary, 0.20 <(NFJ2 / (1-NFJ3)) 0.5 ≦ 0.45 is satisfied, and Mg having a particle diameter of 0.1 μm or more is satisfied. The average number of compounds containing P is 0.5 / μm 2 or less. . [Selection diagram] None

Description

  The present invention relates to a copper alloy for electronic and electrical equipment suitable for electronic and electrical equipment parts such as terminals and bus bars such as connectors and bus bars, and a copper alloy plate for electronic and electrical equipment comprising the copper alloy for electronic and electrical equipment. The present invention relates to strips, electronic / electrical equipment parts, terminals, and bus bars.

Conventionally, copper or copper alloys having high conductivity have been used for electronic and electrical equipment parts such as connectors, press-fit terminals, and bus bars.
Here, with the increase in current of electronic devices and electric devices, large parts of electronic / electric device parts used in these electronic devices and electric devices are used to reduce the current density and diffuse heat due to Joule heat generation. And thickening. For this reason, the material which comprises the component for electronic / electric equipment is calculated | required by high electrical conductivity, the punching workability at the time of a press work, and the favorable bending workability. In addition, stress relaxation resistance is also required for connector terminals used in high-temperature environments such as automobile engine rooms.

  Here, for example, Patent Documents 1 and 2 propose Cu-Mg alloys as materials used for terminals for connectors and press-fit, and parts for electronic and electrical equipment such as bus bars.

JP 2007-056297 A JP 2014-114464 A

Here, in the Cu-Mg alloy described in Patent Document 1, since the P content is as high as 0.08 to 0.35 mass%, cold workability and bending workability are insufficient, and the predetermined It was difficult to mold a part for electronic / electrical equipment of the shape.
Moreover, in the Cu-Mg alloy described in Patent Document 2, the Mg content is 0.01 to 0.5 mass%, and the P content is 0.01 to 0.5 mass%. From this, coarse crystallized products were formed, and cold workability and bending workability were insufficient.

Furthermore, in the above-mentioned Cu—Mg-based alloy, the viscosity of the copper alloy melt is increased by Mg, so that there is a problem that castability is lowered unless P is added.
Further, as described above, with the increase in current of electronic devices and electric devices in recent years, the materials constituting the components for electronic and electric devices are being made thicker. However, as the thickness increases, there is a problem that the burr height generated at the time of punching becomes high, and the punching workability at the time of press working is lowered.
Further, as the thickness increases, a large bending stress tends to act during bending, and therefore, particularly when performing complicated bending, superior bending workability is required as compared with the conventional case.

  The present invention has been made in view of the above-described circumstances, and is a copper alloy for electronic / electric equipment that is excellent in conductivity, strength, bending workability, stress relaxation resistance, castability, and punching workability, An object of the present invention is to provide a copper alloy sheet material for electrical equipment and electronic / electric equipment parts, terminals, and bus bars made of this copper alloy sheet material for electronic and electrical equipment.

In order to solve this problem, the present inventors have intensively studied. As a result, the contents of Mg and P contained in the alloy are set within the range of a predetermined relational expression, and further, relatively coarse Mg and P By restricting the average number of compounds that contain Mg, the crystallized material containing Mg and P is prevented from becoming coarse, and the strength, stress relaxation resistance, and castability are improved without reducing bending workability. The knowledge that it was possible to get it.
Moreover, in the above-mentioned copper alloy, as a result of analyzing the parent phase by the EBSD method with the plane orthogonal to the width direction of rolling as the observation plane, the ratio of the special grain boundary and the random grain boundary constituting the grain boundary triple point is By defining, it was found that cracks are likely to progress along the grain boundary during press working, and the punching workability during press working can be improved.

In order to solve this problem, the copper alloy for electronic / electrical equipment of the present invention includes Mg in a range of 0.15 mass% to less than 0.35 mass%, and P in a range of 0.0005 mass% to less than 0.01 mass%. And the balance consists of Cu and inevitable impurities, and the Mg content [Mg] and the P content [P] satisfy the relationship of [Mg] + 20 × [P] <0.5 by mass ratio. The CI value analyzed by the data analysis software OIM using a plane orthogonal to the rolling width direction as an observation plane and measuring the measurement area of 10000 μm ² or more with a measurement interval of 0.25 μm steps by the EBSD method Is analyzed except for the measurement points with 0.1 or less, the crystal grain boundary is defined as the crystal grain boundary between the measurement points where the orientation difference between adjacent measurements exceeds 15 °, and the corresponding grain boundary of Σ29 or less is defined as the special grain boundary. The random grain boundaries The time, in the grain boundary triple point parsed from OIM, the percentage of the total grain boundary triple points of all three grain boundaries which constitute the grain boundary triple point is the special grain boundary J3 and NF _J3, the grain boundary triple point are two grain boundaries special grain boundaries which constitute the, when one is a percentage of the total grain boundary triple point J2 is a random grain boundary was _{NF J2, 0.20 <(NF J2} / (1-NF J3 )) ^0.5 ≦ 0.45 is established, and the average number of compounds containing Mg and P having a particle size of 0.1 μm or more is 0.5 or less per μm ² in scanning electron microscope observation. It is characterized by being.

Note that the EBSD method means an electron beam diffraction diffraction pattern (EBSD) using a scanning electron microscope with a backscattered electron diffraction image system, and OIM means a crystal orientation using measurement data obtained by EBSD. Is a data analysis software (Orientation Imaging Microscopy: OIM). Further, the CI value is a reliability index (Confidence Index), which is displayed as a numerical value representing the reliability of crystal orientation determination when analyzed using the analysis software OIM Analysis (Ver. 7.2) of the EBSD device. (For example, “EBSD Reader: Using OIM (Revised 3rd Edition)” written by Seiichi Suzuki, September 2009, published by TSL Solutions, Inc.).
Here, when the structure of the measurement point measured by the EBSD method and analyzed by the OIM is a processed structure, since the crystal pattern is not clear, the reliability of determining the crystal orientation is lowered and the CI value is lowered. In particular, when the CI value is 0.1 or less, it is determined that the structure of the measurement point is a processed structure.

The special grain boundary is a Σ value defined crystallographically based on CSL theory (Kronberg et al: Trans. Met. Soc. AIME, 185, 501 (1949)) and corresponding to 3 ≦ Σ ≦ 29. The specific corresponding portion lattice orientation defect Dq at the grain boundary is Dq ≦ 15 ° / Σ1 / 2 (DG Brandon: Acta. Metallurgica. Vol. 14, p. 1479, ( 1966)).
On the other hand, a random grain boundary is a grain boundary other than a special grain boundary that has a corresponding orientation relationship with a Σ value of 29 or less and satisfies Dq ≦ 15 ° / Σ1 / 2.

The grain boundary triple points are J0, where all three grain boundaries are random grain boundaries, J1, two grain boundaries where one grain boundary is a special grain boundary and two grain boundaries are random grain boundaries. There are four types: J2 which is a special grain boundary and one is a random grain boundary, and J3 is a special grain boundary.
Accordingly, the ratio NF _J3 of all three grain boundaries constituting the grain boundary triple point to the all grain boundary triple points of J3, which is a special grain boundary, is defined as NF _J3 = J3 / (J0 + J1 + J2 + J3).
Further, the ratio NF _J2 to the total grain boundary triple point of J2 where two grain boundaries constituting the triple boundary point are special grain boundaries and one is a random grain boundary is defined as NF _J2 = J2 / (J0 + J1 + J2 + J3). Is done.

According to the copper alloy for electronic and electrical equipment having the above-described configuration, the Mg content is in the range of 0.15 mass% or more and less than 0.35 mass%, so that Mg is dissolved in the copper matrix. As a result, the strength and stress relaxation resistance can be improved without greatly reducing the electrical conductivity.
Moreover, since P is contained in the range of 0.0005 mass% or more and less than 0.01 mass%, the viscosity of the molten copper alloy containing Mg can be lowered, and the castability can be improved.
The Mg content [Mg] and the P content [P] are in a mass ratio and satisfy the relationship [Mg] + 20 × [P] <0.5. It is possible to suppress the formation of crystallized substances and to suppress the decrease in cold workability and bending workability.

In addition, the surface orthogonal to the width direction of the rolling was used as the observation surface, and the CI was analyzed by the data analysis software OIM by measuring the measurement area of 10000 μm ² or more by the EBSD method at a measurement interval of 0.25 μm steps. Analysis is performed excluding measurement points with a value of 0.1 or less, and crystal grain boundaries are defined between the measurement points where the orientation difference between adjacent measurements exceeds 15 °, and corresponding grain boundaries of Σ29 or less are designated as special grain boundaries. When the grain boundaries other than the above are used as random grain boundaries, the ratio of J3, which is a special grain boundary, to all three grain boundaries constituting the grain boundary triple point in the grain boundary triple point analyzed from the OIM is NF _J3 When the ratio of two grain boundaries composing the grain boundary triple point is a special grain boundary and one is a random grain boundary with respect to the total grain boundary triple point is NF _J2 , 0.20 <(NF _J2 / (1-NF _J3 )) ^{0. Since 5} ≦ 0.45 is satisfied, cracks easily develop along the grain boundaries, and the punching workability during press working can be improved.

In the observation with a scanning electron microscope, the average number of compounds containing Mg and P having a particle size of 0.1 μm or more is 0.5 pieces / μm ² or less. Thus, a relatively coarse compound containing Mg and P which is the starting point is not dispersed in a large amount, and the bending workability is improved. Accordingly, it is possible to mold terminals such as connectors having complicated shapes, and parts for electronic and electric devices such as relays and lead frames.

Here, in the copper alloy for electronic / electrical equipment of the present invention, the electrical conductivity is preferably more than 75% IACS.
In this case, since the electrical conductivity is sufficiently high, it can be applied to applications that conventionally use pure copper.

Further, in the copper alloy for electronic and electrical equipment of the present invention, the Mg content [Mg] and the P content [P] satisfy the relationship of [Mg] / [P] ≦ 400 by mass ratio. preferable.
In this case, the castability can be reliably improved by defining the ratio of the Mg content that lowers the castability and the P content that improves the castability as described above.

Furthermore, in the copper alloy for electronic / electrical equipment of the present invention, it is preferable that the 0.2% yield strength when a tensile test is performed in a direction parallel to the rolling direction is 300 MPa or more.
In this case, since the 0.2% proof stress when the tensile test is performed in the direction parallel to the rolling direction is 300 MPa or more, it is not easily deformed, and a connector or press for large current / high voltage. It is particularly suitable as a copper alloy for parts for electronic devices such as terminals for fittings and bus bars.

Moreover, in the copper alloy for electronic / electrical equipment of this invention, it is preferable that a residual stress rate is 75% or more in 150 degreeC and 1000 hours.
In this case, since the residual stress rate is defined as described above, permanent deformation can be suppressed to a small level even when used in a high temperature environment, and for example, a decrease in contact pressure of a connector terminal or the like is suppressed. be able to. Therefore, it can be applied as a material for electronic device parts used in a high temperature environment such as an engine room.

The copper alloy sheet material for electronic / electrical equipment of the present invention is made of the above-mentioned copper alloy for electronic / electrical equipment and has a thickness of more than 0.5 mm.
According to the copper alloy sheet material for electronic / electrical equipment of this configuration, it is composed of the above-mentioned copper alloy for electronic / electrical equipment, so that it has conductivity, strength, bending workability, stress relaxation resistance, punching processing. It is particularly suitable as a material for electronic and electrical equipment parts such as thickened connectors, press-fit terminals, and bus bars.

Here, in the copper alloy sheet material for electronic / electrical equipment of the present invention, it is preferable to have a Sn plating layer or an Ag plating layer on the surface.
In this case, since it has a Sn plating layer or an Ag plating layer on the surface, it is particularly suitable as a material for electronic / electric equipment parts such as connectors, terminals such as press-fit, and bus bars. In the present invention, “Sn plating” includes pure Sn plating or Sn alloy plating, and “Ag plating” includes pure Ag plating or Ag alloy plating.

The component for electronic / electrical equipment of the present invention is characterized by comprising the above-described copper alloy sheet material for electronic / electrical equipment. Note that the electronic / electric equipment parts in the present invention include terminals such as connectors and press-fit, bus bars, and the like.
Since the electronic / electrical device parts having this configuration are manufactured using the above-described copper alloy sheet material for electronic / electrical devices, it is a case where the size is increased and the wall thickness is increased in response to a large current application. Can also exhibit excellent characteristics.

The terminal of the present invention is characterized by comprising the above-described copper alloy sheet material for electronic and electrical equipment.
Since the terminal of this structure is manufactured using the above-mentioned copper alloy sheet material for electronic and electrical equipment, it has excellent characteristics even when it is enlarged and thickened in response to a large current application. It can be demonstrated.

The bus bar of the present invention is characterized by comprising the above-described copper alloy sheet material for electronic and electrical equipment.
The bus bar with this configuration is manufactured using the above-mentioned copper alloy sheet material for electronic and electrical equipment, so it has excellent characteristics even when it is enlarged and thickened for high current applications. It can be demonstrated.

  According to the present invention, copper alloy for electronic / electric equipment, copper alloy sheet material for electronic / electric equipment excellent in electrical conductivity, strength, bending workability, stress relaxation resistance, castability, and punching workability, and There can be provided electronic / electric equipment parts, terminals, and bus bars made of the copper alloy sheet material for electronic / electric equipment.

It is a flowchart of the manufacturing method of the copper alloy for electronic and electric apparatuses which is this embodiment.

Below, the copper alloy for electronic and electric apparatuses which is one Embodiment of this invention is demonstrated.
The copper alloy for electronic and electrical devices according to the present embodiment includes Mg in a range of 0.15 mass% to less than 0.35 mass%, P in a range of 0.0005 mass% to less than 0.01 mass%, and the balance being It has a composition consisting of Cu and inevitable impurities.
Here, the content [Mg] of Mg and the content [P] of P are mass ratios,
[Mg] + 20 × [P] <0.5
Have the relationship.

Moreover, in the copper alloy for electronic / electrical equipment which is one embodiment of the present invention, a measurement area of 10000 μm ² or more is measured at an interval of 10000 μm ² by an EBSD method using a surface orthogonal to the width direction of rolling as an observation surface. Measured in steps of 0.25 μm and analyzed except for the measurement points where the CI value analyzed by the data analysis software OIM is 0.1 or less. Between the measurement points where the azimuth difference between adjacent measurements exceeds 15 ° When the grain boundary is a grain boundary, the corresponding grain boundary of Σ29 or less is a special grain boundary, and the other is a random grain boundary, all three grain boundaries constituting the grain boundary triple point are analyzed in the three grain boundary triple points analyzed from OIM The ratio of J3, which is a special grain boundary, to 3 grain boundaries of NF _J3 is NF _J3. Two grain boundaries constituting the 3 grain boundaries are special grain boundaries, and one is a random grain boundary. the ratio of 3 emphasis _{NF J2} When you,
0.20 <(NF _J2 / (1-NF _J3 )) ^0.5 ≦ 0.45
Is supposed to hold.

And in the copper alloy for electronic / electric equipment which is one embodiment of the present invention, the average number of compounds containing Mg and P having a particle size of 0.1 μm or more is 0.5 in the observation with a scanning electron microscope. / Μm ² or less.

In the present embodiment, the Mg content [Mg] and the P content [P] are in a mass ratio.
[Mg] / [P] ≦ 400
It is preferable to have the following relationship.

Moreover, in the copper alloy for electronic / electrical equipment which is this embodiment, it is preferable that electrical conductivity exceeds 75% IACS.
Furthermore, in the copper alloy for electronic / electrical equipment which is this embodiment, it is preferable that the 0.2% yield strength when a tensile test is performed in a direction parallel to the rolling direction is 300 MPa or more. That is, in this embodiment, it is a rolled material of a copper alloy for electronic and electrical equipment, and the 0.2% yield strength when performing a tensile test in a direction parallel to the rolling direction in the final rolling process is the above-mentioned. It is defined as follows.
Moreover, in the copper alloy for electronic and electrical equipment which is this embodiment, it is preferable that the residual stress rate is 75% or more at 150 ° C. for 1000 hours.

  Here, the reason for defining the component composition, the crystal structure, and various characteristics as described above will be described below.

(Mg: 0.15 mass% or more and less than 0.35 mass%)
Mg is an element having an action of improving strength and stress relaxation resistance while maintaining high electrical conductivity by being dissolved in a parent phase of a copper alloy.
Here, when the content of Mg is less than 0.15 mass%, there is a possibility that the effect cannot be sufficiently achieved. On the other hand, when the Mg content is 0.35 mass% or more, the electrical conductivity is greatly lowered, the viscosity of the molten copper alloy is increased, and castability may be lowered.
From the above, in the present embodiment, the Mg content is set within a range of 0.15 mass% or more and less than 0.35 mass%.
In order to further improve the strength and stress relaxation resistance, the lower limit of the Mg content is preferably 0.16 mass% or more, more preferably 0.17 mass% or more, and 0.18 mass%. More preferably. Moreover, in order to reliably suppress a decrease in conductivity and a decrease in castability, the upper limit of the Mg content is preferably 0.32 mass% or less, more preferably 0.30 mass% or less, More preferably, it is 0.28 mass% or less.

(P: 0.0005 mass% or more and less than 0.01 mass%)
P is an element having an effect of improving castability.
Here, when content of P is less than 0.0005 mass%, there exists a possibility that the effect cannot be fully achieved. On the other hand, when the content of P is 0.01 mass% or more, a coarse crystallized product containing Mg and P is generated. This crystallized product becomes a starting point of fracture, and during cold working or bending. There is a risk of cracking during processing.
From the above, in the present embodiment, the P content is set within a range of 0.0005 mass% or more and less than 0.01 mass%. In order to surely improve the castability, the lower limit of the P content is preferably 0.001 mass% or more, and more preferably 0.002 mass% or more. Moreover, in order to suppress the production | generation of a coarse crystallized substance reliably, it is preferable to make the upper limit of P content into less than 0.009 mass%, and it is further more preferable to set it as less than 0.008 mass%. It is more preferable to set it to 0075 mass% or less.

([Mg] + 20 × [P] <0.5)
As described above, coexistence of Mg and P produces a crystallized product containing Mg and P.
Here, when the Mg content [Mg] and the P content [P] are [Mg] + 20 × [P] is 0.5 or more in terms of mass ratio, The total amount is large, and crystallized substances containing Mg and P are coarsened and distributed in high density, and there is a risk that cracks are likely to occur during cold working or bending.
From the above, in this embodiment, [Mg] + 20 × [P] is set to less than 0.5. Note that [Mg] + 20 × [P] is set to 0.48 in order to reliably suppress the coarsening and densification of the crystallized product and to suppress the occurrence of cracks during cold working or bending. It is preferably less than 0.46, more preferably less than 0.46.

([Mg] / [P] ≦ 400)
Since Mg is an element that has the effect of increasing the viscosity of the molten copper alloy and decreasing the castability, in this embodiment, in order to further improve the castability, the content of Mg and P It is preferable to optimize the ratio.
Here, when the Mg content [Mg] and the P content [P] are set to a mass ratio, the [Mg] / [P] ratio is 400 or less, so that the ratio of the Mg and P content is Therefore, it is possible to reliably achieve the effect of improving the castability by adding P.
From the above, in this embodiment, it is preferable to set [Mg] / [P] to 400 or less in order to further improve the castability. In order to further improve the castability, [Mg] / [P] is more preferably 350 or less, and more preferably 300 or less.
In addition, when [Mg] / [P] is excessively low, Mg is consumed as a crystallized product, and there is a possibility that the effect due to solid solution of Mg cannot be obtained. In order to suppress generation of crystallized substances containing Mg and P, and to surely improve the yield strength and stress relaxation resistance due to solid solution of Mg, the lower limit of [Mg] / [P] is set to more than 20 Is more preferable, and it is more preferable that it is more than 25.

(Inevitable impurities: 0.1 mass% or less)
Other inevitable impurities include Ag, B, Ca, Sr, Ba, Sc, Y, rare earth elements, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru , Os, Co, Se, Te, Rh, Ir, Ni, Pd, Pt, Au, Zn, Cd, Hg, Al, Ga, In, Ge, Sn, As, Sb, Tl, Pb, Bi, Be, N , C, Si, Li, H, O, S and the like. Since these inevitable impurities have the effect of lowering the conductivity, the total amount is set to 0.1 mass% or less.
In addition, Ag, Zn, and Sn are easily mixed in copper to lower the electrical conductivity, so that the total amount is preferably less than 500 massppm.
Furthermore, since Si, Cr, Ti, Zr, Fe, and Co particularly reduce the electrical conductivity greatly and deteriorate the bending workability due to the formation of inclusions, the total amount of these elements is preferably less than 500 massppm.

(Ratio of grain boundary 3 points)
The punching workability at the time of press working is more excellent as the burr height at break is smaller. Here, as the thickness of the material to be pressed increases, the burr height tends to increase relatively.
In order to reduce the burr height at the time of press working, it is sufficient that the fracture occurs promptly along the grain boundary at the time of press working. When the network of random grain boundaries becomes long, breakage along the grain boundaries tends to occur. In order to increase the network length of the random grain boundary, all three grain boundaries constituting the triple boundary of grain boundaries are J3, which is a special grain boundary represented by Σ29 or less, or two of the three grain boundaries are special grain boundaries. It is important to control the ratio of J2.

Therefore, in this embodiment, the surface perpendicular to the width direction of rolling is taken as the observation surface, and the measurement area of 10000 μm ² or more is measured at a measurement interval of 0.25 μm by the EBSD method. Analyzed except for the measurement point with CI value of 0.1 or less analyzed by OIM, the crystal grain boundary is between the measurement points where the orientation difference between adjacent measurements exceeds 15 °, and the corresponding grain boundary of Σ29 or less When a special grain boundary is used and the other grain boundaries are random grain boundaries, all three grain boundaries constituting the three grain boundaries are special grain boundaries in the three grain boundary triple points analyzed from the OIM. When the ratio to the emphasis is NF _J3 , the two grain boundaries constituting the grain boundary 3 emphasis are special grain boundaries, and one is the random grain boundary, the ratio of J2 to all grain boundaries 3 emphasis is NF _J2 .
0.20 <(NF _J2 / (1-NF _J3 )) ^0.5 ≦ 0.45
To be satisfied.

Here, when (NF _J2 / (1-NF _J3 )) ^0.5 exceeds 0.45, the network length of random grain boundaries becomes relatively short, and the network length of special grain boundaries becomes long. The burr height during processing increases. On the other hand, when (NF _J2 / (1-NF _J3 )) ^0.5 is 0.20 or less, the structure is substantially processed, so that bending workability is lowered. For this reason, in this embodiment, (NF _J2 / (1-NF _J3 )) ^{0.5 is set} to be in a range of more than 0.20 and not more than 0.45.
The lower limit of (NF _J2 / (1-NF _J3 )) ^0.5 is preferably 0.21 or more, more preferably 0.22 or more, and more preferably 0.23 or more. preferable. On the other hand, the upper limit of (NF _J2 / (1-NF _J3 )) ^0.5 is preferably 0.40 or less, and more preferably 0.35 or less.

(Average number of compounds containing Mg and P with a particle size of 0.1 μm or more)
If the number of relatively coarse compounds containing Mg and P having a particle size of 0.1 μm or more increases, cracks may occur starting from the compound during bending. In particular, when performing complicated bending, cracks are likely to occur.
For this reason, in this embodiment, the average number of compounds containing Mg and P having a particle size of 0.1 μm or more is limited to 0.5 / μm ² or less.
In order to further improve the bending workability, it is preferable to limit the average number of compounds containing Mg and P having a particle size of 0.05 μm or more to 1.0 / μm ² or less.

(Conductivity: over 75% IACS)
In the copper alloy for electronic / electric equipment according to the present embodiment, by setting the conductivity to exceed 75% IACS, it can be used favorably as a terminal for connectors, press-fit, etc., and parts for electronic / electric equipment such as bus bars. Can do.
The electrical conductivity is preferably more than 76% IACS, more preferably more than 77% IACS, and more preferably more than 78% IACS.

(0.2% proof stress: 300 MPa or more)
In the copper alloy for electronic / electric equipment according to the present embodiment, by setting the 0.2% proof stress to 300 MPa or more, it is particularly suitable as a material for electronic / electric equipment parts such as connectors, terminals such as press-fit, and bus bars. It will be a thing. In the present embodiment, the 0.2% yield strength when the tensile test is performed in the direction parallel to the rolling direction is set to 300 MPa or more.
Here, the 0.2% proof stress described above is preferably 325 MPa or more, and more preferably 350 MPa or more.

(Residual stress ratio: 75% or more)
In the copper alloy for electronic / electric equipment according to the present embodiment, as described above, the residual stress rate is 75% or more at 150 ° C. for 1000 hours.
When the residual stress rate under these conditions is high, permanent deformation can be suppressed even when used in a high temperature environment, and a decrease in contact pressure can be suppressed. Therefore, the copper alloy for electronic / electric equipment according to the present embodiment can be applied as a terminal used in a high temperature environment such as around the engine room of an automobile. In the present embodiment, the residual stress ratio obtained by performing the stress relaxation test in the direction parallel to the rolling direction is set to 75% or more at 150 ° C. for 1000 hours.
The residual stress rate is preferably 77% or more at 150 ° C. and 1000 hours, and more preferably 80% or more at 150 ° C. and 1000 hours.

  Next, a method for manufacturing a copper alloy for electronic / electric equipment according to the present embodiment having such a configuration will be described with reference to the flowchart shown in FIG.

(Melting / Casting Process S01)
First, the above-described elements are added to a molten copper obtained by melting a copper raw material to adjust the components, thereby producing a molten copper alloy. In addition, an element simple substance, a mother alloy, etc. can be used for the addition of various elements. Moreover, you may melt | dissolve the raw material containing the above-mentioned element with a copper raw material. Moreover, you may use the recycling material and scrap material of this alloy. Here, the molten copper is preferably so-called 4NCu having a purity of 99.99 mass% or more, or so-called 5NCu having a purity of 99.999 mass% or more. In the melting process, in order to suppress the oxidation of Mg and to reduce the hydrogen concentration, the atmosphere is dissolved in an inert gas atmosphere (for example, Ar gas) having a low vapor pressure of H ₂ O, and the holding time at the time of melting is minimized. It is preferable that the

Then, the copper alloy molten metal whose components are adjusted is poured into a mold to produce an ingot. In consideration of mass production, it is preferable to use a continuous casting method or a semi-continuous casting method.
At this time, since the compound containing Mg and P is formed as a crystallized product during solidification of the molten metal, it becomes possible to make the size of the compound containing Mg and P finer by increasing the solidification rate. . Therefore, the cooling rate during casting is preferably 0.5 ° C./sec or more, more preferably 1 ° C./sec or more, and most preferably 15 ° C./sec or more.

(Homogenization step S02)
Next, heat treatment is performed to homogenize the obtained ingot. Inside the ingot, there may be a portion where Mg is segregated during the solidification process, and an intermetallic compound mainly composed of Cu and Mg generated by segregation and increasing the Mg concentration. Therefore, in order to eliminate or reduce these segregation and intermetallic compounds, etc., by performing a heat treatment to heat the ingot to 300 ° C. or more and 900 ° C. or less, Mg can be uniformly diffused in the ingot. Mg is dissolved in the matrix. The homogenization step S02 is preferably performed in a non-oxidizing or reducing atmosphere.

  Here, when the heating temperature is less than 300 ° C., solutionization is incomplete, and a large amount of intermetallic compounds mainly containing Cu and Mg may remain in the matrix phase. On the other hand, when the heating temperature exceeds 900 ° C., a part of the copper material becomes a liquid phase, and the structure and the surface state may become non-uniform. Therefore, the heating temperature is set in the range of 300 ° C. or higher and 900 ° C. or lower. The heating temperature is preferably 500 ° C. or higher, more preferably 600 ° C. or higher.

(Hot processing step S03)
Since Mg segregation is likely to occur at the grain boundaries, the presence of the Mg segregation portion makes it difficult to control the triple point of the grain boundaries. Moreover, there is a possibility that a coarse intermetallic compound or the like mainly composed of Cu and Mg generated by the segregation and concentration of Mg.
Therefore, hot working is performed after the above-described homogenization step S02 in order to eliminate the segregation of Mg and make the structure uniform.
The total processing rate of hot working is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more.
In this case, the processing method is not particularly limited, and for example, rolling, wire drawing, extrusion, groove rolling, forging, pressing, and the like can be employed. The hot working temperature is preferably in the range of 400 ° C. or higher and 900 ° C. or lower.

(Solution process S04)
In order to thoroughly eliminate Mg segregation at the grain boundaries, solution heat treatment is performed after the aforementioned hot working step S03. The solution heat treatment may be performed under the condition of holding at 500 ° C. to 900 ° C. for 1 second to 10 hours. This step may also serve as the aforementioned hot working step S03. In that case, the end temperature of hot working should be over 500 ° C., and it should be kept at 500 ° C. or more for 10 seconds or more after the end of hot working.
Here, when the heating temperature is less than 500 ° C., solutionization is incomplete, and a large amount of intermetallic compounds mainly containing Cu and Mg may remain in the matrix phase. On the other hand, when the heating temperature exceeds 900 ° C., a part of the copper material becomes a liquid phase, and the structure and the surface state may become non-uniform. Therefore, the heating temperature in the solution treatment step S04 is set in the range of 500 ° C. or higher and 900 ° C. or lower.

(Roughing process S05)
In order to process into a predetermined shape, rough processing is performed. In this roughing step S05, warm processing at 100 ° C. or higher and 350 ° C. or lower is performed once or more. By performing warm processing at 100 ° C. or higher and 350 ° C. or lower, it is possible to increase the extremely small recrystallization region during processing, and the structure is randomized during recrystallization in the subsequent intermediate heat treatment step S06. At the same time, the total number of random grain boundaries can be increased, and the value of NFJ ₂ / (1-NFJ ₃ )) ^0.5 can be set to a desired range. When the warm processing is performed once, it is performed in the final step of the rough processing step. Further, instead of warm processing, processing heat generated by increasing the processing rate per processing step may be used. In that case, for example, in rolling, the processing rate per pass is preferably 15% or more, preferably 20% or more, more preferably 30% or more. The number of warm workings is desirably two or more. Regarding the temperature of warm working, the lower limit temperature is preferably 150 ° C. or higher, more preferably 200 ° C. or higher. The upper limit is 350 ° C. or lower so that grain growth after recrystallization does not occur remarkably, but it is preferably 325 ° C. or lower, more preferably lower than 300 ° C.

(Intermediate heat treatment step S06)
After the roughing step S05, heat treatment is performed for the purpose of recrystallization structure for increasing the number ratio of random grain boundaries and softening for improving workability. The heat treatment method is not particularly limited, but the heat treatment is preferably performed in a non-oxidizing atmosphere or a reducing atmosphere at a holding temperature of 400 ° C. to 900 ° C. and a holding time of 10 seconds to 10 hours. Moreover, the cooling method after heating is not particularly limited, but it is preferable to adopt a method such as water quenching in which the cooling rate is 200 ° C./min or more.
Note that the roughing step S05 and the intermediate heat treatment step S06 may be repeatedly performed.

(Finishing process S07)
Finishing is performed to process the copper material after the intermediate heat treatment step S06 into a predetermined shape. In this finishing step S07, the dislocations introduced during the processing are quickly rearranged to bring the value of NFJ ₂ / (1-NFJ ₃ )) ^0.5 to a desired range, and further, stress relaxation resistance characteristics In order to improve the temperature, warm processing at 50 ° C. or higher and lower than 300 ° C. is performed at least once. By performing warm processing at 50 ° C. or more and less than 300 ° C., the dislocations introduced during the processing are rearranged, so that the stress relaxation resistance is improved. In the finishing process, the processing method and the processing rate differ depending on the final shape. However, in the case of a strip or plate, rolling may be performed. Moreover, what is necessary is just to set it as normal cold processing about processes other than 1 time or more warm processing. Instead of warm processing at 50 ° C. or more and less than 300 ° C., the processing heat generated by increasing the processing rate per processing step may be used. In that case, for example, in rolling, the processing rate per pass may be 10% or more.
Further, the processing rate is appropriately selected so as to approximate the final shape. However, in order to improve the strength by work hardening, the processing rate is preferably set to 20% or more. Also. When further improving the strength, the processing rate is more preferably 30% or more, and the processing rate is more preferably 40% or more. More preferably, it is 50% or more.

(Finishing heat treatment step S08)
Next, a finish heat treatment is performed on the plastic workpiece obtained in the finishing step S07 in order to improve stress relaxation resistance and low-temperature annealing hardening, or to remove residual strain. The heat treatment temperature is preferably in the range of 100 ° C. or higher and 800 ° C. or lower. In this finishing heat treatment step S08, it is necessary to set heat treatment conditions (temperature, time, cooling rate) in order to suppress the number ratio of special grain boundaries at the triple boundary of grain boundaries by recrystallization. For example, in the range of 200 ° C. to 300 ° C., the holding time is preferably 10 seconds or longer and 10 hours or shorter. This heat treatment is preferably performed in a non-oxidizing atmosphere or a reducing atmosphere. The method of heat treatment is not particularly limited, but heat treatment at high temperature and short time in a continuous annealing furnace is preferable from the viewpoint of reducing the manufacturing cost.
Furthermore, the above-described finishing step S07 and the finishing heat treatment step S08 may be repeated.

  In this way, the copper alloy for electronic / electric equipment (copper alloy sheet material for electronic / electric equipment) according to the present embodiment is produced. There is no particular upper limit on the thickness of the copper alloy sheet material for electronic and electrical equipment, but when the copper alloy sheet material for electronic and electrical equipment is made into a connector, terminal, or bus bar by pressing, the thickness is 5.0 mm. Exceeding the load significantly increases the load on the press and reduces the productivity per unit time, resulting in an increase in cost. For this reason, in this embodiment, it is preferable that the thickness of the copper alloy sheet material for electronic / electric equipment is 0.5 mm or more and 5.0 mm or less. The lower limit of the thickness of the copper alloy sheet material for electronic / electric equipment is preferably more than 1.0 mm, more preferably 1.5 mm or more, and more preferably 2.0 mm or more. More preferably, the thickness exceeds 3.0 mm.

Here, the copper alloy sheet material for electronic / electrical equipment according to the present embodiment may be used as it is for electronic / electrical equipment parts as it is. An Sn plating layer or an Ag plating layer of about 100 μm may be formed.
Furthermore, by using a copper alloy for electronic / electric equipment (copper alloy strip for electronic / electric equipment) according to the present embodiment as a raw material, for example, a terminal such as a connector or a press fit, Parts for electronic and electrical equipment such as bus bars are molded.

According to the copper alloy for electronic and electrical equipment according to the present embodiment configured as described above, the Mg content is in the range of 0.15 mass% or more and less than 0.35 mass%. When Mg is dissolved in the matrix, the strength and stress relaxation resistance can be improved without greatly reducing the electrical conductivity.
Moreover, since P is contained in the range of 0.0005 mass% or more and less than 0.01 mass%, castability can be improved.

  Further, since the Mg content [Mg] and the P content [P] are in a mass ratio and satisfy the relationship of [Mg] + 20 × [P] <0.5, the coarse crystals of Mg and P Generation | occurrence | production of a product can be suppressed and it can suppress that cold work property and bending workability fall.

In addition, the surface orthogonal to the width direction of the rolling was used as the observation surface, and the CI was analyzed by the data analysis software OIM by measuring the measurement area of 10000 μm ² or more by the EBSD method at a measurement interval of 0.25 μm steps. Analysis is performed excluding measurement points with a value of 0.1 or less, and crystal grain boundaries are defined between the measurement points where the orientation difference between adjacent measurements exceeds 15 °, and corresponding grain boundaries of Σ29 or less are designated as special grain boundaries. When the grain boundaries other than the above are used as random grain boundaries, the ratio of J3, which is a special grain boundary, to all three grain boundaries constituting the grain boundary triple point in the grain boundary triple point analyzed from the OIM is NF _J3 When two grain boundaries constituting the grain boundary triple point are special grain boundaries, and one is a random grain boundary, the ratio of J2 to all grain boundary triple points is NF _J2 .
_{0.20 <(NF J2 / (1} -NF J3)) 0.5 ≦ 0.45
Therefore, the length of the random grain boundary network is long, and the fracture along the grain boundary occurs promptly at the time of press working, so that the press punching workability is also excellent.

And in the copper alloy for electronic and electric devices which is this embodiment, in scanning electron microscope observation, the average number of the compound containing Mg and P with a particle size of 0.1 micrometer or more is 0.5 piece / micrometer < ² >. Since it is set as follows, many compounds containing coarse Mg and P which are the starting points of cracking are not dispersed in the matrix, and the bending workability is improved. Accordingly, it is possible to mold terminals such as connectors having complicated shapes, and parts for electronic and electric devices such as relays and lead frames.

  Further, in the present embodiment, preferably, the Mg content [Mg] and the P content [P] are in a mass ratio and satisfy the relationship of [Mg] / [P] ≦ 400. The ratio between the content of Mg to be reduced and the content of P that improves castability is optimized, and the castability can be reliably improved by the effect of addition of P.

  Furthermore, in the copper alloy for electronic / electric equipment according to the present embodiment, the 0.2% yield strength when the tensile test is performed in the direction parallel to the rolling direction is 300 MPa or more, and the conductivity is 75%. Since it is over IACS, it is suitable for thickening parts for electronic and electrical equipment due to high voltage and large current, and it is suitable for terminals for connectors and press fits, and parts for electronic and electrical equipment such as bus bars. Particularly suitable as a material.

  In addition, in the copper alloy for electronic and electrical equipment according to the present embodiment, the residual stress ratio is 75% or more at 150 ° C. for 1000 hours, so that permanent deformation occurs even when used in a high temperature environment. For example, a decrease in contact pressure of a connector terminal or the like can be suppressed. Therefore, it can be applied as a material for electronic device parts used in a high temperature environment such as an engine room.

Moreover, since the copper alloy sheet material for electronic / electrical equipment which is this embodiment is comprised with the above-mentioned copper alloy for electronic / electrical equipment, it is bent into this copper alloy sheet material for electronic / electrical equipment. By performing the above, it is possible to manufacture terminals for connectors and press fits, and parts for electronic and electrical devices such as bus bars.
In addition, when the Sn plating layer or the Ag plating layer is formed on the surface, it is particularly suitable as a material for electronic / electric equipment parts such as connectors, terminals such as press-fit, and bus bars.

  Furthermore, since the electronic / electric equipment parts (terminals such as connectors and press-fit, bus bars, etc.) according to the present embodiment are composed of the above-described copper alloy for electronic / electric equipment, they are increased in size and thickness. Can also exhibit excellent characteristics.

As described above, the copper alloy for electronic / electric equipment, the copper alloy sheet material for electronic / electric equipment, and the parts for electronic / electric equipment (terminals, bus bars, etc.) according to the embodiments of the present invention have been described. It is not limited and can be changed as appropriate without departing from the technical idea of the invention.
For example, in the above-described embodiment, an example of a method for producing a copper alloy for electronic / electric equipment has been described. However, the method for producing a copper alloy for electronic / electric equipment is not limited to that described in the embodiment. The existing manufacturing method may be selected as appropriate.

Below, the result of the confirmation experiment performed in order to confirm the effect of this invention is demonstrated.
A copper raw material made of oxygen-free copper (ASTM B152 C10100) having a purity of 99.99 mass% or more was prepared, charged in a high-purity graphite crucible, and high-frequency melted in an atmosphere furnace having an Ar gas atmosphere. Various additive elements were added to the obtained molten copper to prepare the component compositions shown in Table 1, and poured into a mold to produce an ingot. Inventive Examples 1 and 11 are heat insulating material (isowool) molds, Inventive Examples 9 and 19 are carbon molds, Comparative Example 2 is an iron mold with a heater having a heating function, Other Invention Examples and Comparative Examples are water-cooled. A copper alloy mold having a function was used as a casting mold. The size of the ingot was about 100 mm thick x about 150 mm wide x about 300 mm long.
The vicinity of the cast surface of the ingot was chamfered. Thereafter, in an Ar gas atmosphere, heating was performed for 4 hours under the temperature conditions shown in Table 2 using an electric furnace to perform a homogenization treatment.

The ingot after the homogenization heat treatment was hot-rolled to a thickness of about 50 mm. Then, it cut | disconnected and heated for 1 hour on the conditions of Table 2 using the electric furnace, and implemented the solution treatment.
After the solution treatment, the rolling roll was heated to 300 ° C. and rough rolling was performed at the rolling rates shown in Table 2.

After rough rolling, an intermediate heat treatment was performed using an electric furnace and a salt bath furnace under the temperature conditions described in Table 2 so that the average crystal grain size was approximately between 5 μm and 15 μm. The heat treatment using an electric furnace was performed in an Ar atmosphere.
The average crystal grain size after the intermediate heat treatment was examined as follows. A surface orthogonal to the width direction of rolling, that is, a TD (Transverse Direction) surface is used as an observation surface, mirror polishing, etching, and then taking an optical microscope so that the rolling direction is next to the photograph, Observation was performed with a 1000 × field of view (approximately 300 × 200 μm ² ). Then, according to the cutting method of JIS H 0501, the crystal grain size is drawn by 5 lines each having a predetermined length in the vertical and horizontal directions, the number of crystal grains to be completely cut is counted, and the average value of the cutting lengths is averaged. Calculated as the crystal grain size.

The copper material that had been subjected to the intermediate heat treatment was appropriately cut into a shape suitable for the final shape, and surface grinding was performed to remove the oxide film. Thereafter, the rolling roll is heated to 200 ° C., and finish rolling (finishing) is performed at the rolling rate described in Table 2. In Examples 1 to 10 of the present invention and Comparative Examples 1 and 4, the thickness of 3. A thin plate having a width of 5 mm and a width of about 150 mm was produced. In addition, in Invention Examples 11 to 20 and Comparative Examples 2 and 3, a thin plate having a thickness of 1.5 mm and a width of about 150 mm was produced. After finishing rolling (finishing processing), an electric furnace or a salt bath furnace was used. A finish heat treatment was carried out under the conditions shown in Table 2 and then water quenching was performed to produce a thin plate for property evaluation.

  And the following items were evaluated. The evaluation results are shown in Table 3.

(Castability)
As an evaluation of castability, the presence or absence of rough skin at the time of casting was observed. The case where the rough skin was hardly observed by visual inspection was indicated by “◎”, the case where the rough skin having a depth of less than 1 mm was generated was indicated by “◯”, and the case where the rough skin was generated by a depth of 1 mm or more and less than 2 mm was indicated by “Δ”. Moreover, the thing where big skin roughness more than depth 2mm generate | occur | produced was set to "x", and evaluation was stopped on the way.
In addition, the depth of rough skin is the depth of rough skin which goes to the center part from the edge part of an ingot.

(Grain boundary 3 priority ratio)
Using a cross-section perpendicular to the rolling width direction, that is, a TD plane (Transverse direction) as an observation plane, an EBSD measuring device and OIM analysis software are used to crystal grain boundaries (special grain boundaries and random grain boundaries) and grains as follows. The triple point of the boundary was measured. After mechanical polishing using water-resistant abrasive paper and diamond abrasive grains, final polishing was performed using a colloidal silica solution. And an EBSD measuring device (Quanta FEG 450 made by FEI, EDAX / TSL (current AMETEK) OIM Data Collection) and analysis software (EDAX / TSL (current AMETEK) OIM Data Analysis ver. ), The orientation difference of each crystal grain is analyzed except for the measurement point where the acceleration value of electron beam is 20 kV, the measurement interval is 10000 μm ² with a measurement interval of 0.25 μm and the CI value is 0.1 or less. A crystal grain boundary was defined between the measurement points where the orientation difference between adjacent measurement points was 15 ° or more. For the three grain boundaries constituting each grain boundary triple point, special grain boundaries and random grain boundaries were identified using the CSL signal value calculated by Neighboring grid point. Corresponding grain boundaries exceeding Σ29 were regarded as random grain boundaries.

(Mechanical properties)
A No. 13B test piece defined in JIS Z 2241 was collected from the strip for characteristic evaluation, and 0.2% proof stress was measured by the offset method of JIS Z 2241. The test piece was collected in a direction parallel to the rolling direction.

(conductivity)
A test piece having a width of 10 mm and a length of 150 mm was taken from the strip for characteristic evaluation, and the electric resistance was determined by a four-terminal method. Moreover, the dimension of the test piece was measured using the micrometer, and the volume of the test piece was calculated. And electrical conductivity was computed from the measured electrical resistance value and volume. In addition, the test piece was extract | collected so that the longitudinal direction might be parallel with the rolling direction of the strip for characteristic evaluation.

(Compound observation)
Mirror polishing and ion etching were performed on the rolled surface of each sample. In order to confirm the compound containing Mg and P, observation was performed using a FE-SEM (field emission scanning electron microscope) at a field of view of about 30,000 times (about 21 μm ² / field of view).
Next, to investigate the density of compounds containing Mg and P (number / [mu] m ^2), at 30,000 times the field of view at the center position of the plate width (about 21 [mu] m ² / field), 5 field (about 105 .mu.m ² ). When determining the field of view, a portion not containing a compound having a particle size of 1 μm or more was selected. As for the particle size of the intermetallic compound, the major axis of the intermetallic compound (the length of the straight line that can be drawn the longest in the grain without contact with the grain boundary in the middle) and the minor axis (in the direction perpendicular to the major axis, the grain in the middle The average value of the length of the straight line that can be drawn the longest under conditions that do not contact the boundary). And the density (piece / micrometer < ² >) of the compound containing Mg and P with a particle size of 0.1 micrometer or more and the compound containing Mg and P with a particle size of 0.05 micrometer or more was calculated | required.

(Bending workability)
Bending was performed in accordance with four test methods of Japan Copper and Brass Association Technical Standard JCBA-T307: 2007. For the inventive examples 1 to 10, a specimen having a width of 3.5 mm and a length of 30 mm is cut from the thin plate for characteristic evaluation so that the bending axis is perpendicular to the rolling direction, and a plurality of specimens are taken. Then, a W-bending test was performed using a W-shaped jig having a bending angle of 90 degrees and a bending radius of 1 mm (R / t = 0.3). For Invention Examples 11 to 20 and Comparative Examples 2 and 3, a test piece having a width of 10 mm and a length of 30 mm was cut and sampled, and the cut surface was polished, and then the bending angle was 90 degrees and the bending radius was 0.00. A W-bending test was performed using a 4 mm (R / t = 0.3) W-shaped jig.
Judgment is made as “X” when a crack is observed by visually observing the outer periphery of the bent portion, “◯” when a large wrinkle is observed, and “◎” when a fracture, a fine crack, or a large wrinkle cannot be confirmed. It was. In addition, (double-circle) and (circle) were judged to be the allowable bending workability. The evaluation results are shown in Table 3.

(Punching workability)
A number of circular holes (φ8 mm) were punched out from the strip for characteristic evaluation with a mold, and evaluation was performed by measuring the burr height.
The die clearance was about 3% of the plate thickness, and punching was performed at a punching speed of 50 spm (stroke per minute). The burr height was measured by observing the cut surface on the punched side, measuring 10 points, and evaluating the ratio with respect to the plate thickness.
The item with the highest burr height is rated as “◎” if it is 2.5% or less of the plate thickness. Those exceeding were evaluated as “x”.

(Stress relaxation characteristics)
In the stress relaxation resistance test, stress was applied by a method according to the cantilevered screw method of Japan Copper and Brass Association Technical Standard JCBA-T309: 2004, and the residual stress ratio after holding for 1000 hours at a temperature of 150 ° C. was measured. .
As a test method, a specimen (width 10 mm) is taken from each characteristic evaluation strip in a direction parallel to the rolling direction, and the initial deflection displacement is performed so that the maximum surface stress of the specimen is 80% of the proof stress. Was set to 2 mm, and the span length was adjusted. The maximum surface stress is determined by the following equation.
Maximum surface stress (MPa) = 1.5 Etδ ₀ / L _s ²
However,
E: Young's modulus (MPa)
t: thickness of the sample described in the table (t = 1.5 mm or 3.5 mm)
δ ₀ : Initial deflection displacement (2 mm)
L _s : Span length (mm)
It is.
Residual stress rate was measured from the bending habit after holding for 1000 hours at a temperature of 150 ° C., and the stress relaxation resistance was evaluated. The residual stress rate was calculated using the following formula.
Residual stress rate (%) = (1−δ _t / δ ₀ ) × 100
However,
δ _t : Permanent deflection displacement after holding for 1000 h at 150 ° C. (mm) −Permanent deflection displacement after holding for 24 h at room temperature (mm)
δ ₀ : Initial deflection displacement (mm)
It is.

In Comparative Example 1, the Mg content was less than the range of the present invention, and the stress relaxation resistance was insufficient.
In Comparative Example 2, the average number of compounds containing Mg and P having a particle size of 0.1 μm or more was large, and the bending workability was “x”.
In Comparative Example 3, the Mg content was larger than the range of the present invention, and [Mg] + 20 × [P] was out of the range of the present invention. Therefore, the bending workability was evaluated as “x”. Furthermore, the conductivity was low. Therefore, no other evaluation was performed.
In Comparative Example 4, since (NF _J2 / (1-NF _J3 )) ^0.5 was outside the scope of the present invention, the network length of random grain boundaries was shortened, and the punching processability was lowered. Therefore, evaluation of bending workability and stress relaxation resistance was not performed.
In Comparative Example 5, [Mg] + 20 × [P] was outside the scope of the present invention, so the workability was poor and large ear cracks occurred during rough rolling. For this reason, subsequent evaluation was stopped.

On the other hand, in the examples of the present invention, it is confirmed that 0.2% proof stress, conductivity, stress relaxation resistance, bending workability, castability, and punching workability are excellent.
From the above, according to the examples of the present invention, the copper alloy for electronic / electric equipment and the copper alloy for electronic / electric equipment excellent in conductivity, strength, bending workability, stress relaxation resistance, castability, punching workability It was confirmed that the strip material can be provided.

Claims (10)

Mg is contained in the range of 0.15 mass% or more and less than 0.35 mass%, P is contained in the range of 0.0005 mass% or more and less than 0.01 mass%, and the balance consists of Cu and inevitable impurities,
Mg content [Mg] and P content [P] are in mass ratio,
[Mg] + 20 × [P] <0.5
Satisfy the relationship
The CI value analyzed by the data analysis software OIM is obtained by measuring the measurement area of 10000 μm ² or more by the EBSD method at a measurement interval of 0.25 μm with the surface orthogonal to the width direction of the rolling as the observation surface. Analysis is performed excluding measurement points that are 0.1 or less, the crystal grain boundaries are between the measurement points where the orientation difference between adjacent measurements exceeds 15 °, the corresponding grain boundaries of Σ29 or less are special grain boundaries, and the others are In the case of random grain boundaries, in the grain boundary triple point analyzed from OIM,
The ratio of all three grain boundaries constituting the grain boundary triple point is a special grain boundary, and the ratio of J3 to all grain boundary triple points is NF _J3, and the two grain boundaries constituting the grain boundary triple point are special grain boundaries, When the ratio of J2 which is one of the random grain boundaries to the triple point of all grain boundaries is NF _J2 ,
0.20 <(NF _J2 / (1-NF _J3 )) ^0.5 ≦ 0.45
As well as
A copper alloy for electronic and electrical equipment, characterized in that the average number of compounds containing Mg and P having a particle size of 0.1 μm or more is 0.5 pieces / μm ² or less in a scanning electron microscope observation .   The copper alloy for electronic and electrical equipment according to claim 1, wherein the electrical conductivity is more than 75% IACS. Mg content [Mg] and P content [P] are in mass ratio,
[Mg] / [P] ≦ 400
The copper alloy for electronic / electric equipment according to claim 1 or 2, wherein the relationship is satisfied.   The electronic / electric equipment according to any one of claims 1 to 3, wherein a 0.2% yield strength when a tensile test is performed in a direction parallel to the rolling direction is 300 MPa or more. Copper alloy.   5. The copper alloy for electronic and electrical equipment according to claim 1, wherein the residual stress ratio is 75% or more at 1000 ° C. for 150 hours.   A copper alloy sheet for electronic and electrical equipment, comprising the copper alloy for electronic and electrical equipment according to any one of claims 1 to 5 and having a thickness exceeding 0.5 mm. Wood.   It has Sn plating layer or Ag plating layer on the surface, The copper alloy sheet | seat material for electronic / electric equipment of Claim 6 characterized by the above-mentioned.   An electronic / electric equipment component comprising the copper alloy sheet material for electronic / electric equipment according to claim 6 or 7.   A terminal comprising the copper alloy sheet material for electronic / electrical equipment according to claim 6 or 7.   A bus bar comprising the copper alloy sheet material for electronic / electrical equipment according to claim 6 or 7.

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