JP6680041B2 - Copper alloys for electronic / electrical devices, plastic alloys for electronic / electrical devices, parts for electronic / electrical devices, terminals, and bus bars - Google Patents

Description

  The present invention relates to a copper alloy for electronic / electrical devices, which is suitable for lead frames, terminals such as connectors and press-fits, and parts for electronic / electrical devices such as bus bars, and electronic / electrical products made of the copper alloy for electronic / electrical devices. The present invention relates to a copper alloy plastic working material for equipment, electronic / electrical equipment parts, terminals, and bus bars.

2. Description of the Related Art Conventionally, copper or copper alloy having high conductivity has been used for electronic and electric equipment parts such as terminals such as connectors and press fits, relays, lead frames, bus bars and the like.
Here, along with the miniaturization of electronic devices and electric devices, the parts for electronic and electric devices used in these electronic devices and electric devices have been made smaller and thinner. For this reason, high strength and good bending workability are required for materials constituting electronic / electrical device parts. In addition, stress relaxation resistance is also required for terminals and the like of connectors used in a high temperature environment such as an automobile engine room.

  Here, for example, Patent Documents 1 and 2 propose a Cu—Mg-based alloy as a material used for parts for electronic / electrical devices such as terminals such as connectors and press fits, relays, lead frames, and bus bars. There is.

JP, 2014-025089, A JP, 2014-114464, A

Here, in the Cu-Mg-based alloy described in Patent Document 1, since the content of Mg is large, the electrical conductivity is insufficient, and it is difficult to apply it to the application requiring high electrical conductivity. there were.
In addition, in the Cu-Mg-based 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%. Therefore, coarse crystallized substances were generated, and cold workability and bendability were insufficient.

  The present invention has been made in view of the above-mentioned circumstances, and is a copper alloy for electronic / electrical devices and a plastic alloy for electronic / electrical devices, which has excellent conductivity, strength, bending workability, and stress relaxation resistance. The object is to provide materials, parts for electronic / electrical devices, terminals, and bus bars.

In order to solve this problem, the copper alloy for electronic / electrical devices of the present invention contains Mg in a range of 0.15 mass% or more and less than 0.35 mass%, the balance being Cu and unavoidable impurities, and being conductive. The rate exceeds 75% IACS, and the measurement area of 1000 μm ² or more is measured by the EBSD method at a measurement interval of 0.5 μm, and the Confidence Index (CI) value analyzed by the data analysis software OIM is 0.1 or less. When the analysis is performed excluding the measurement points, the lengths of the low-angle grain boundaries and the subgrain boundaries between the measurement points at which the azimuth difference between the adjacent measurement points is 2 ° or more and 15 ° or less are L _LB , and the adjacent measurement is performed. When the length of the large-angle tilt grain boundary between the measurement points where the orientation difference between the points exceeds 15 ° is L _HB , the following formula is characterized.
L _LB / (L _LB + L _HB )> 20%
The CI value is a value measured by the analysis software OIM Analysis (Ver.6.2) of the EBSD device, and the Voting method should be used when indexing the EBSD pattern obtained from a certain analysis point. And takes a value from 0 to 1. Since the CI value is a value that evaluates the reliability of indexing and orientation calculation, when the CI value is low, that is, when a crystal pattern with a clear analysis point cannot be obtained, strain (working structure) exists in the structure. It can be said that they are doing.

According to the copper alloy for electronic / electrical devices having the above-described configuration, the Mg content is set to be in the range of 0.15 mass% or more and less than 0.35 mass%, so that Mg forms a solid solution in the mother phase of copper. As a result, the strength and stress relaxation resistance can be improved without significantly reducing the conductivity. Specifically, since the electric conductivity is set to exceed 75% IACS, it can be applied to an application requiring high electric conductivity.
The low-angle grain boundaries and the subgrain boundaries are regions where the density of dislocations introduced during processing is high. Therefore, when the proportion of these is high, the strength (proof stress) is improved by work hardening due to the increase in dislocation density. Can be made. In the present invention, since the lengths of the small-angle grain boundaries and the subgrain boundaries are set to 20% or more with respect to the length of all grain boundaries, it is possible to improve the strength while maintaining the conductivity. It will be possible.

Here, in the copper alloy for an electrical and electronic equipment of the present invention, further look including the P in the range of less than 0.0005 mass% or more 0.01 mass%, the Mg content [Mg] (mass%) and the P the content (P) (mass%) is preferably that meets the relation of [Mg] + 20 × [P] ≦ 0.51.
In this case, the addition of P can reduce the viscosity of the copper alloy molten metal containing Mg and improve the castability.
Further, it is possible to suppress the formation of coarse crystallized substances containing Mg and P, and it is possible to suppress deterioration of cold workability and bending workability.

Furthermore, when P is contained in the above range in the copper alloy for electronic / electrical devices of the present invention, the Mg content [Mg] (mass%) and the P content [P] (mass%) are It is preferable to satisfy the relational expression [Mg] / [P] ≦ 400.
In this case, the castability can be reliably improved by defining the ratio of the content of Mg that lowers the castability and the content of P that improves the castability as described above.

Further, in the copper alloy for electronic / electrical equipment of the present invention, it is preferable that the 0.2% proof stress when the tensile test is performed in the direction orthogonal to the rolling direction is 300 MPa or more.
In this case, since the 0.2% proof stress when a tensile test is performed in the direction orthogonal to the rolling direction is defined as described above, it is not easily deformed and a terminal such as a connector or press fit, It is especially suitable as a copper alloy for electronic and electrical equipment parts such as relays, lead frames and bus bars.

The copper alloy plastic working material for electronic / electrical equipment of the present invention is characterized by being made of the above-mentioned copper alloy for electronic / electrical equipment.
According to the copper alloy plastic working material for electronic / electrical equipment of this configuration, since it is composed of the above-mentioned copper alloy for electronic / electrical equipment, it has excellent conductivity, strength, bending workability, and stress relaxation resistance. Therefore, it is particularly suitable as a material for electronic and electrical equipment parts such as terminals for connectors and press fits, relays, lead frames, bus bars and the like.

Here, in the copper alloy plastically worked 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 an Sn plating layer or an Ag plating layer on the surface, it is particularly suitable as a material for terminals for connectors, press-fitting, etc., parts for electronic / electrical devices such as relays, lead frames, bus bars and the like. In addition, in this invention, "Sn plating" includes pure Sn plating or Sn alloy plating, and "Ag plating" includes pure Ag plating or Ag alloy plating.

A component for electronic / electrical equipment of the present invention is characterized by comprising the above-described copper alloy plastically worked material for electronic / electrical equipment. The electronic / electrical device parts in the present invention include terminals such as connectors and press fits, relays, lead frames, bus bars and the like.
Since the electronic / electrical device component of this configuration is manufactured using the above-mentioned copper alloy plastically worked material for electronic / electrical device, it should exhibit excellent characteristics even when it is made smaller and thinner. You can

A terminal of the present invention is characterized by being made of the above-mentioned copper alloy plastically worked material for electronic / electrical devices.
Since the terminal having this configuration is manufactured using the above-described copper alloy plastically worked material for electronic / electrical devices, it is possible to exhibit excellent characteristics even when the terminal is downsized and thinned.

A bus bar of the present invention is characterized by being made of the above-described copper alloy plastically worked material for electronic / electrical devices.
Since the bus bar having this structure is manufactured using the above-described copper alloy plastic-worked material for electronic / electrical devices, it can exhibit excellent characteristics even when it is downsized and thinned.

  According to the present invention, conductivity, strength, bending workability, copper alloy for electronic / electrical devices excellent in stress relaxation resistance, copper alloy plastically processed material for electronic / electrical devices, parts for electronic / electrical devices, terminals, And a bus bar can be provided.

It is a flow figure of a manufacturing method of a copper alloy for electronic and electric equipment which is this embodiment.

Below, the copper alloy for electronic and electric equipment which is one embodiment of the present invention is explained.
The copper alloy for electronic / electrical devices according to the present embodiment has a composition containing Mg in the range of 0.15 mass% or more and less than 0.35 mass%, and the balance Cu and unavoidable impurities.
In addition, in the copper alloy for electronic / electrical devices of the present embodiment, the electrical conductivity is set to exceed 75% IACS.

Further, in the copper alloy for electronic / electrical equipment of the present embodiment, the measurement area of 1000 μm ² or more is measured by the EBSD method at the measurement interval of 0.5 μm, and the CI value analyzed by the data analysis software OIM is 0. When the analysis is performed excluding the measurement points of 1 or less, the lengths of the small-angle grain boundaries and the subgrain boundaries between the measurement points at which the azimuth difference between the adjacent measurement points is 2 ° or more and 15 ° or less are L _LB , where L _HB is the length of the high-angle grain boundary between the measurement points where the azimuth difference between the adjacent measurement points exceeds 15 °, the following formula is established.
L _LB / (L _LB + L _HB )> 20%
The CI value is a parameter indicating the clarity of the pattern at the measurement point, and a clear pattern cannot be obtained at the measurement point with a CI value of 0.1 or less, so that an accurate crystal orientation cannot be measured. Therefore, when measuring the above-mentioned azimuth difference, analysis is performed except for the point where the CI value is 0.1 or less.

The copper alloy for electronic / electrical devices according to the present embodiment may further contain P in a range of 0.0005 mass% or more and less than 0.01 mass%.
When P is contained in the above-mentioned range in the copper alloy for electronic / electrical equipment of the present embodiment, the content [Mg] (Mg%) of Mg and the content [P] (Mass%) of P are
[Mg] + 20 × [P] <0.5
The relational expression of is satisfied.
Further, in the present embodiment, the Mg content [Mg] (mass%) and the P content [P] (mass%) are
[Mg] / [P] ≦ 400
The relational expression of is satisfied.

  The 0.2% proof stress of the copper alloy for electronic / electrical devices according to the present embodiment is set to 300 MPa or more.

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

(Mg: 0.15 mass% or more and less than 0.35 mass%)
Since Mg forms a solid solution in the mother phase of the copper alloy, it becomes possible to improve the strength and the stress relaxation resistance without significantly reducing the conductivity.
Here, when the content of Mg is less than 0.15 mass%, there is a possibility that the action and effect cannot be sufficiently exerted. On the other hand, when the content of Mg is 0.35 mass% or more, the conductivity may be significantly reduced, the viscosity of the molten copper alloy may be increased, and the castability may be reduced.
From the above, in the present embodiment, the Mg content is set within the range of 0.15 mass% or more and less than 0.35 mass%.
In addition, in order to further improve the strength and the stress relaxation resistance, the lower limit of the Mg content is preferably 0.18 mass% or more, and more preferably 0.2 mass% or more. Further, in order to reliably suppress the decrease in conductivity and the decrease in castability, the upper limit of the Mg content is preferably 0.32 mass% or less, and more preferably 0.3 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. Further, by forming a compound with Mg, it also has the function of reducing the recrystallized grain size.
Here, when the content of P is less than 0.0005 mass%, there is a possibility that the action and effect cannot be sufficiently exerted. On the other hand, when the P content is 0.01 mass% or more, the above-mentioned crystallized product containing Mg and P is coarsened, and this crystallized substance becomes a starting point of fracture, and during cold working or Cracks may occur during bending.
From the above, when P is added in the present embodiment, the content of P is set within the range of 0.0005 mass% or more and less than 0.01 mass%. In order to reliably improve the castability, the lower limit of the P content is preferably 0.0007 mass% or more, and more preferably 0.001 mass% or more. Further, in order to reliably suppress the formation of coarse crystallized substances, the upper limit of the P content is preferably less than 0.009 mass%, more preferably less than 0.008 mass%, and even more preferably 0. Most preferably, it is 0075 mass% or less.

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

([Mg] / [P] ≦ 400)
Since Mg is an element that increases the viscosity of the molten copper alloy and reduces the castability, it is necessary to optimize the content ratio of Mg and P in order to reliably improve the castability. There is.
Here, when the content of Mg is [Mg] and the content of P is [P] in mass%, and [Mg] / [P] exceeds 400, the ratio of Mg to P is There is a possibility that the content is increased and the effect of improving the castability by adding P is reduced.
From the above, when P is added in this embodiment, [Mg] / [P] is set to 400 or less. In order to further improve the castability, [Mg] / [P] is preferably 350 or less, more preferably 300 or less.
When [Mg] / [P] is excessively low, Mg is consumed as a crystallized substance, and the effect due to solid solution of Mg may not be obtained. In order to suppress the formation of crystallized substances containing Mg and P and to surely improve the yield strength and stress relaxation resistance due to the solid solution of Mg, the lower limit of [Mg] / [P] is set to more than 20. Preferably, it is more preferably 25 or more.

(Inevitable impurities: 0.1 mass% or less)
Other unavoidable impurities include Ag, B, Ca, Sr, Ba, Sc, Y, rare earth elements, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe and 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. These unavoidable impurities have the effect of lowering the conductivity, so the total amount is made 0.1 mass% or less.
Further, Ag, Zn, and Sn are easily mixed in copper to reduce the conductivity, so that the total amount is preferably less than 500 mass ppm.
Furthermore, Si, Cr, Ti, Zr, Fe, and Co particularly greatly reduce conductivity and deteriorate bending workability due to the formation of inclusions. Therefore, the total amount of these elements is preferably less than 500 mass ppm.

(Low-angle grain boundary and subgrain boundary length ratio: L _LB / (L _HB + L _LB ))
Since the low-angle grain boundaries and the subgrain boundaries are regions where the density of dislocations introduced during processing is high, the low-angle grain boundaries and the subgrain boundary length ratio L _LB / (L _HB + L _{LB) in all} grain boundaries By controlling so that the above formula satisfies the following formula, the strength (proof stress) can be improved by work hardening accompanied by an increase in dislocation density.
L _LB / (L _LB + L _HB )> 20%
The low-angle grain boundaries and the subgrain boundary length ratio L _LB / (L _HB + L _LB ) are preferably 25% or more, and more preferably 30% or more even within the above range. On the other hand, if the small-angle grain boundaries and the subgrain boundary length ratio L _LB / (L _HB + L _LB ) are too high, the ductility may decrease and bending workability may be deteriorated. Therefore, the tilt grain boundaries and the subgrain boundaries may be deteriorated. The length ratio L _LB / (L _HB + L _LB ) is preferably 90% or less, and more preferably 80% or less.

(Conductivity: over 75% IACS)
In the copper alloy for electronic / electrical equipment of the present embodiment, by setting the electrical conductivity to exceed 75% IACS, it can be used as a component for electronic / electrical equipment such as terminals such as connectors and press fits, relays, lead frames, and bus bars. It can be used well.
The electrical conductivity is preferably 76% IACS or more, more preferably 77% IACS or more, further preferably 78% IACS or more, and further preferably 80% IACS or more.

(0.2% proof stress: 300 MPa or more)
In the copper alloy for electronic / electrical devices according to the present embodiment, the 0.2% proof stress is set to 300 MPa or more, so that terminals such as connectors and press fits, electronic / electrical device parts such as relays, lead frames, and busbars can be obtained. It is particularly suitable as a material for. In this embodiment, the 0.2% proof stress when the tensile test is performed in the direction orthogonal to the rolling direction is 300 MPa or more.
Here, the above-mentioned 0.2% proof stress is preferably 325 MPa or more, and more preferably 350 MPa or more.

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

(Melting / casting process S01)
First, the above-mentioned elements are added to a molten copper obtained by melting a copper raw material to adjust the components, and a molten copper alloy is produced. Here, the copper melt 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. It should be noted that a simple element, a mother alloy, or the like can be used to add various elements. Moreover, you may melt | dissolve the raw material containing the above-mentioned element with a copper raw material. Also, recycled materials and scrap materials of the present alloy may be used. In the melting process, in order to suppress the oxidation of Mg and to reduce the hydrogen concentration, the atmosphere is melted in an inert gas atmosphere (for example, Ar gas) with a low vapor pressure of H ₂ O, and the holding time during melting is minimized. It is preferable to keep

Then, the molten copper alloy having the adjusted components is poured into a mold to produce an ingot. In consideration of mass production, it is preferable to use the continuous casting method or the semi-continuous casting method.
At this time, since a crystallized substance containing Mg and P is formed during solidification of the molten metal, the crystallized substance size can be made finer by increasing the solidification rate. Therefore, the cooling rate of the molten metal is preferably 0.1 ° C./sec or more, more preferably 0.5 ° C./sec or more, and most preferably 1 ° C./sec or more.

(Heating step S02)
Next, heat treatment is performed for homogenization and solution treatment of the obtained ingot. Inside the ingot, Cu and an intermetallic compound containing Mg as the main components, which are generated by the segregation of Mg during the solidification process, are present. Therefore, in order to eliminate or reduce such segregation and intermetallic compounds, a heat treatment of heating the ingot to 400 ° C. or more and 900 ° C. or less is performed to uniformly diffuse Mg in the ingot. , Mg is dissolved in the matrix. The heating step S02 is preferably performed in a non-oxidizing or reducing atmosphere.

  Here, if the heating temperature is less than 400 ° C., solution treatment may be incomplete, and a large amount of intermetallic compounds containing Cu and Mg as main components may remain in the mother phase. On the other hand, if the heating temperature exceeds 900 ° C., a part of the copper material may be in a liquid phase, and the texture and surface condition may be non-uniform. Therefore, the heating temperature is set in the range of 400 ° C. or higher and 900 ° C. or lower. The temperature is more preferably 400 ° C. or higher and 850 ° C. or lower, and further preferably 420 ° C. or higher and 800 ° C. or lower.

(Hot working step S03)
In order to increase the efficiency of rough processing and make the structure uniform, hot working is performed after the above-described heating step S02. At this time, the processing method is not particularly limited, hot rolling when the final shape is a plate or strip, extrusion or groove rolling when the final shape is a wire or bar, and when the final shape is a bulk shape. Forging or pressing may be applied. Further, in order to thoroughly perform homogenization and suppress localization of small-angle grain boundaries, the hot working temperature is preferably in the range of 400 ° C to 900 ° C, and is in the range of 450 ° C to 800 ° C. Is more preferable, and it is optimum that the temperature is in the range of 450 ° C. or higher and 750 ° C. or lower.

(Quenching process S04)
After the hot working step S03, a quenching step S04 of cooling to a temperature of 200 ° C. or lower at a cooling rate of 60 ° C./min or higher is performed.

(Rough processing step S05)
Roughing is performed to form a predetermined shape. The temperature condition in this rough working step S05 is not particularly limited, but in order to suppress recrystallization or to improve dimensional accuracy, it is cold or warm rolling within a range of -200 ° C to 200 ° C. Is preferable, and room temperature is particularly preferable. The processing rate (rolling rate) is preferably 20% or more, more preferably 30% or more. The processing method is not particularly limited, and for example, rolling, wire drawing, extrusion, groove rolling, forging, pressing and the like can be adopted.

(Intermediate heat treatment step S06)
After the rough processing step S05, heat treatment is performed for the purpose of thorough solution treatment, recrystallization structure or 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. or more and 900 ° C. or less and a holding time of 10 seconds or more and 10 hours or less. When the crystal grains are fine, specifically, when the crystal grain size is 3 μm or less, the low-angle grain boundaries and the subgrain boundary length ratio L _LB / (L _HB + L _LB ) tend to be low. The heat treatment temperature is preferably 500 ° C. or higher and 900 ° C. or lower.
Further, the cooling method after heating is not particularly limited, but it is preferable to adopt a method such as water quenching that provides a cooling rate of 200 ° C./min or more.
The rough processing 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 addition, the temperature condition in this finishing step S07 is not particularly limited, but is within a range of -200 ° C. to 200 ° C. in which cold working or warm working is performed to suppress recrystallization or softening. Is preferable, and room temperature is particularly preferable. Further, the working ratio is appropriately selected so as to approximate the final shape, but in the finishing working step S07, the small tilt angle grain boundary and the subgrain boundary length ratio are increased to improve the strength by work hardening. In addition, it is preferable that the processing rate is 35% or more. Also. When further improving the strength, the working rate is more preferably 40% or more, further preferably 45% or more. On the other hand, the processing rate is preferably 90% or less, and more preferably 85% or less in order to suppress the deterioration of the bending workability due to the excessive increase of the small-angle grain boundary and the subgrain boundary. . The working rate is generally the area reduction rate of rolling or wire drawing.

(Finishing heat treatment step S08)
Next, the plastically worked material obtained in the finishing step S07 is subjected to finishing heat treatment for improving stress relaxation resistance and low temperature annealing hardening, or for removing residual strain.
If the heat treatment temperature is too high, the low-angle grain boundaries and the subgrain boundary length ratio L _LB / (L _HB + L _LB ) are greatly reduced, so the heat treatment temperature should be in the range of 100 ° C. to 800 ° C. Is preferable, and it is more preferable to set it in the range of 200 ° C. or higher and 700 ° C. or lower. In this finishing heat treatment step S08, it is necessary to set the heat treatment conditions (temperature, time, cooling rate) so as to avoid a significant decrease in strength due to recrystallization.
For example, at 300 ° C., it is preferable to hold for 1 second to 120 seconds. 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 short-time heat treatment in a continuous annealing furnace is preferable from the effect of reducing manufacturing cost.
Further, the finishing processing step S07 and the finishing heat treatment step S08 described above may be repeatedly performed.

  In this way, a rolled plate (thin plate) is produced as the copper alloy plastically worked material for electronic / electrical equipment according to the present embodiment. The thickness of the copper alloy plastically worked material (thin plate) for electronic / electrical devices is in the range of more than 0.05 mm and less than 3.0 mm, preferably in the range of more than 0.1 mm and less than 3.0 mm. It is said that. If the thickness of the copper alloy plastically worked material (thin plate) for electronic / electrical equipment is 0.05 mm or less, it is unsuitable for use as a conductor for large current applications, and if the thickness exceeds 3.0 mm. However, press punching becomes difficult.

Here, the copper alloy plastically worked material for electronic / electrical equipment according to the present embodiment may be used as it is for a component for electronic / electrical equipment. You may form a Sn plating layer or Ag plating layer of about 100 micrometers. At this time, the plate thickness of the copper alloy plastically worked material for electronic / electrical devices is preferably 10 to 1000 times the plating layer thickness.
Further, by using a copper alloy for electronic / electrical equipment (copper alloy plastic working material for electronic / electrical equipment) of the present embodiment as a material, punching or bending is performed, for example, a terminal such as a connector or press fit, Parts for electronic and electrical equipment such as relays, lead frames and bus bars are molded.

According to the copper alloy for an electronic / electrical device of the present embodiment configured as described above, since the content of Mg is within the range of 0.15 mass% or more and less than 0.35 mass%, Since Mg forms a solid solution in the matrix, it becomes possible to improve the strength and the stress relaxation resistance without significantly reducing the conductivity.
Further, in the copper alloy for electronic / electrical equipment according to the present embodiment, since the electrical conductivity is set to 75% IACS or more, the copper alloy for electronic / electrical devices can be applied to applications requiring high electrical conductivity.

Then, in the copper alloy for electronic / electrical equipment of the present embodiment, the low-angle grain boundaries and the subgrain boundary length ratio L _LB / (L _HB + L _LB ) measured by the EBSD method is set to 20% or more. Therefore, the strength (proof stress) can be improved by work hardening accompanied by an increase in dislocation density. Therefore, it is possible to improve the strength while maintaining the conductivity.

In addition, when P is added to the copper alloy for electronic / electrical equipment according to the present embodiment and the content of P is within the range of 0.0005 mass% or more and less than 0.01 mass%, the viscosity of the molten copper alloy is It is possible to reduce the castability and improve the castability.
Since the Mg content [Mg] (mass%) and the P content [P] (mass%) satisfy the relational expression of [Mg] + 20 × [P] <0.5, Mg It is possible to suppress the formation of coarse crystallized substances of P and P, and to suppress the deterioration of cold workability and bendability.
Further, in the present embodiment, the Mg content [Mg] (mass%) and the P content [P] (mass%) satisfy the relational expression [Mg] / [P] ≦ 400. The ratio of the content of Mg that lowers the castability and the content of P that improves the castability is optimized, and the effect of adding P can surely improve the castability.

  Furthermore, in the copper alloy for electronic / electrical devices according to the present embodiment, the 0.2% proof stress when the tensile test is performed in the direction orthogonal to the rolling direction is set to 300 MPa or more, so that the connector or the press fit is performed. It is especially suitable as a material for parts for electronic and electrical equipment such as terminals, relays, lead frames, bus bars, etc.

Further, since the copper alloy plastically worked material for electronic / electrical equipment according to the present embodiment is made of the above-mentioned copper alloy for electronic / electrical equipment, it is possible to bend the copper alloy plastically worked material for electronic / electrical equipment into a bent material. By doing so, it is possible to manufacture terminals for connectors, press fits, etc., parts for electronic / electrical devices such as relays, lead frames, bus bars and the like.
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 terminals for connectors, press-fitting, etc., parts for electronic / electrical devices such as relays, lead frames, bus bars and the like.

  Further, the electronic / electrical device parts (terminals such as connectors and press-fits, relays, lead frames, bus bars, etc.) according to the present embodiment are made of the above-described copper alloy for electronic / electrical devices, and thus can be miniaturized. And even if the thickness is reduced, excellent characteristics can be exhibited.

The copper alloy for electronic / electrical devices, the copper alloy plastic-worked material for electronic / electrical devices, and the parts for electronic / electrical devices (terminals, bus bars, etc.), which are the embodiments of the present invention, have been described above. The present invention is not limited, and can be appropriately changed 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 / electrical equipment has been described, but the method for producing a copper alloy for electronic / electrical equipment is not limited to the one described in the embodiment. Alternatively, an existing manufacturing method may be appropriately selected and manufactured.

Below, the result of the confirmation experiment conducted in order to confirm the effect of the present invention will be described.
A copper raw material made of oxygen-free copper (ASTM B152 C10100) with a purity of 99.99 mass% or more was prepared, charged into a high-purity graphite crucible, and subjected to high frequency melting in an atmosphere furnace in an Ar gas atmosphere. Various additive elements were added to the obtained molten copper to prepare the component composition shown in Table 1, and the molten copper was poured into a mold to produce an ingot. Inventive Example 3 is a heat insulating material (isowool) mold, Inventive Example 23 is a carbon mold, Inventive Examples 1-2, 4-22, 24-32, and Comparative Examples 1-5 are copper alloys having a water cooling function. The mold was used as a casting mold. The size of the ingot was about 100 mm in thickness × about 200 mm in width × about 100 mm in length.

The vicinity of the casting surface of this ingot was chamfered, and the ingot was cut out and the size was adjusted so that the plate thickness of the final product was 0.5 mm.
This block was heated and held under the temperature conditions shown in Table 2 for 4 hours in an Ar gas atmosphere. Then, the block after heating and holding was subjected to hot rolling under the conditions shown in Table 2 and water quenching.

Then, after performing rough rolling under the conditions shown in Table 2, heat treatment was performed under a temperature condition shown in Table 2 using a salt bath.
The heat-treated copper material was appropriately cut into a shape suitable for the final shape, and surface grinding was performed to remove the oxide film. Then, at room temperature, finish rolling (finishing) was carried out at a rolling rate shown in Table 2 to produce a thin plate having a thickness of 0.5 mm, a width of about 150 mm, and a length of 200 mm.
Then, after finish rolling (finishing), finish heat treatment was performed in an Ar atmosphere under the conditions shown in Table 2, and then water quenching was performed to prepare a thin plate for property evaluation.

(Castability)
As an evaluation of the castability, the presence or absence of rough skin during the above-mentioned casting was observed. The case where no or almost no rough skin was visually observed was rated as ⊚, the case where a small rough surface with a depth of less than 1 mm occurred was rated as ○, and the rough surface with a depth of 1 mm or more and less than 2 mm was rated as Δ. In addition, the case where a large skin roughness with a depth of 2 mm or more occurred was marked with x and the evaluation was stopped halfway. The evaluation results are shown in Table 3.
The rough skin depth is the depth of rough skin from the end portion to the central portion of the ingot.

(Mechanical properties)
A No. 13B test piece specified in JIS Z 2241 was sampled from the characteristic evaluation strip, and 0.2% proof stress was measured by the offset method of JIS Z 2241. The test pieces were taken in a direction orthogonal to the rolling direction. The evaluation results are shown in Table 3.

(conductivity)
A test piece having a width of 10 mm and a length of 150 mm was sampled from the characteristic evaluation strip, and the electrical resistance was determined by the four-terminal method. The dimension of the test piece was measured using a micrometer, and the volume of the test piece was calculated. Then, the conductivity was calculated from the measured electric resistance value and the volume. In addition, the test piece was sampled in a direction in which the longitudinal direction was orthogonal to the rolling direction of the characteristic evaluation strip. The evaluation results are shown in Table 3.

(Bending workability)
Bending was performed according to the 4 test methods of Japan Copper and Brass Association technical standard JCBA-T307: 2007. A plurality of test pieces with a width of 10 mm and a length of 30 mm were sampled from the thin plate for characteristic evaluation so that the axis of bending was orthogonal to the rolling direction, and the bending angle was 90 degrees and the bending radius was 0.3 mm (R / A W-bending test was performed using a W-type jig with t = 0.6).
When cracks are observed visually by observing the outer periphery of the bent portion, `` X '' is judged, when large wrinkles are observed, it is judged as ◯, and when fracture or fine cracks or large wrinkles cannot be confirmed, judgment is made as ◎. It was It should be noted that ⊚ and ○ were judged to be acceptable bending workability. The evaluation results are shown in Table 3.

(Low-angle grain boundary and sub-grain boundary length ratio)
A surface perpendicular to the rolling width direction, that is, a TD surface (Transverse direction) is used as an observation surface, and an EBSD measuring device and an OIM analysis software are used to determine the crystal grain boundaries (small tilt angle boundary and subgrain boundary and A large tilt grain boundary) and a crystal orientation difference distribution were measured.

After mechanical polishing was performed using water-resistant polishing paper and diamond abrasive grains, final polishing was performed using a colloidal silica solution. Then, an EBSD measuring apparatus (Quanta FEG 450 manufactured by FEI, OIM Data Collection manufactured by EDAX / TSL (current AMETEK) and analysis software (manufactured by EDAX / TSL (current AMETEK) OIM Data Analysis ver. 6.2). ), The misorientation of each crystal grain is analyzed except for the measurement point where the accelerating voltage of the electron beam is 20 kV, the measurement interval is 0.5 μm step, the measurement area is 1000 μm ² or more, and the CI value is 0.1 or less. , A small tilt angle grain boundary and a subgrain boundary between measurement points at which the azimuth difference between adjacent measurement points is 2 ° or more and 15 ° or less, and the length is L _LB , and a large tilt angle between measurement points exceeding 15 ° the length and grain boundaries with L _HB, low-angle grain boundaries in the total grain boundaries and sub-grain boundary length ratio _LB / a _(L LB ₊ L _HB) was determined.

  When analyzing grain boundaries, a so-called clean-up process is performed to correct and replace measurement points with low CI values from the azimuth relationship of surrounding points in order to remove the effects of contamination, foreign matter, and pits on the sample surface. However, in this example, in order to correctly evaluate the small-angle grain boundaries and the subgrain boundary length, the analysis is performed without performing the cleanup process.

In Comparative Examples 1 and 2, the content of Mg was less than the range of the present invention and the strength was insufficient.
In Comparative Examples 3 and 4, the content of Mg was larger than the range of the present invention, and the conductivity was low.
In Comparative Example 5, the low-angle grain boundaries and the subgrain boundary length ratio L _LB / (L _LB + L _HB ) were less than the range of the present invention, and the strength was insufficient.

On the other hand, it is confirmed that the example of the present invention is excellent in 0.2% proof stress, conductivity and bending workability. It is also confirmed that when P is added, the castability is excellent.
From the above, it was confirmed that the example of the present invention can provide a copper alloy for electronic / electrical equipment and a copper alloy plastically worked material for electronic / electrical equipment, which are excellent in conductivity, strength, and bending workability.

Claims (9)

Mg in the range of 0.15 mass% or more and less than 0.35 mass%, the balance consisting of Cu and inevitable impurities,
With conductivity exceeding 75% IACS,
The measurement area of 1000 μm ² or more was measured by the EBSD method at a measurement interval of 0.5 μm, and the analysis was performed by the data analysis software OIM except for the measurement points having a CI value of 0.1 or less, and adjacent measurement points were analyzed. Between the measurement points where the misorientation between them is 2 ° or more and 15 ° or less, the length of the low-angle grain boundary and the subgrain boundary is L _LB , and the misorientation between the adjacent measurement points exceeds 15 °. When the length of the high-angle grain boundary is L _HB , the following formula is established, and a copper alloy for electronic and electric devices.
L _LB / (L _LB + L _HB )> 20% Further seen including the P in the range of less than 0.0005 mass% or more 0.01 mass%, the Mg content [Mg] (mass%) and the content of P (P) (mass%) is,
[Mg] + 20 × [P] ≦ 0.51
The copper alloy for electronic / electrical devices according to claim 1, which satisfies the following relational expression . The content of Mg [Mg] (mass%) and the content of P [P] (mass%) are
[Mg] / [P] ≦ 400
The copper alloy for electronic / electrical devices according to claim 2, which satisfies the relational expression of. The copper alloy for electronic / electrical equipment according to claim 3, which has a 0.2% proof stress of 300 MPa or more when a tensile test is performed in a direction orthogonal to the rolling direction. A copper alloy plastically worked material for electronic / electrical equipment, comprising the copper alloy for electronic / electrical equipment according to claim 1 . The copper alloy plastic working material for electronic / electrical equipment according to claim 5, which has a Sn plating layer or an Ag plating layer on its surface. A component for electronic / electrical equipment, comprising the copper alloy plastically worked material for electronic / electrical equipment according to claim 5 or 6 . A terminal comprising the copper alloy plastically worked material for electronic / electrical equipment according to claim 5 or 6 . A bus bar comprising the copper alloy plastically worked material for electronic / electrical devices according to claim 5 or 6 .

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