JP6226098B2 - Copper alloy for electronic and electrical equipment, copper alloy sheet material for electronic and electrical equipment, electronic and electrical equipment parts, terminals, bus bars, and movable pieces for relays - Google Patents

Description

  The present invention relates to a copper alloy for electronic / electrical equipment suitable for electronic / electrical equipment parts such as terminals such as connectors and press-fit, lead frames, bus bars, relay movable pieces, etc., and this copper alloy for electronic / electrical equipment The present invention relates to a copper alloy sheet material for electronic / electric equipment, parts for electronic / electric equipment, terminals, bus bars, and a movable piece for relay.

Conventionally, copper or copper alloy having high conductivity has been used for electronic / electric equipment parts such as terminals such as connectors and press fits, movable pieces for relays, lead frames, bus bars and the like.
Here, along with the downsizing of electronic devices and electrical devices, parts for electronic and electrical devices used in these electronic devices and electrical devices are being made smaller and thinner. For this reason, the material which comprises the components for electronic / electrical devices is calculated | required by high intensity | strength and favorable bending workability. In addition, stress relaxation resistance is also required for connector terminals used in high-temperature environments such as automobile engine rooms.

  For example, Patent Documents 1 and 2 propose Cu-Mg alloys as materials used for electronic and electrical device parts such as connectors, press-fit terminals, relay movable pieces, lead frames, bus bars, and the like. Yes.

Japanese Patent No. 5045783 JP 2014-114464 A

Here, in the Cu-Mg based alloy described in Patent Document 1, since the Mg content is large, the conductivity is insufficient, and it is difficult to apply to applications that require high conductivity. there were.
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%. Coarse compounds that greatly deteriorate cold workability and bending workability are not considered, and cold workability and bending workability are insufficient.

Furthermore, in the above-mentioned Cu-Mg type | system | group alloy, since the viscosity of a copper alloy molten metal raises with Mg, there existed a problem that castability will fall unless P is added.
Recently, with the reduction in weight of electronic and electrical devices, the thickness of electronic and electrical device parts such as connectors, movable pieces for relays, lead frames, etc. used in these electronic devices and electrical devices has been reduced. It is illustrated. For this reason, in a terminal such as a connector, it is necessary to perform severe bending work in order to ensure contact pressure, and bending workability is required more than ever.

  The present invention has been made in view of the above-described circumstances, and is excellent in electrical conductivity and bending workability for electronic and electrical equipment copper alloys, electronic and electrical equipment copper alloy strips, and electronic and electrical equipment use. It aims at providing a movable piece for components, a terminal, a bus bar, and a relay.

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%. In addition, the balance is made of Cu and inevitable impurities, the electrical conductivity is over 75% IACS, and the average number of compounds containing Mg and P having a particle size of 0.1 μm or more is observed under a scanning electron microscope. 0.5 pieces / μm ² or less.

  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. Specifically, since the electrical conductivity exceeds 75% IACS, it can also be applied to applications that require high 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.

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 large amount of coarse Mg and P-containing compounds that are the starting points of the above are not dispersed, and the bending workability is improved. Therefore, it becomes possible to mold terminals for complicated shapes such as connectors, movable pieces for relays, parts for electronic and electric devices such as lead frames, and the like.

Here, in the copper alloy for electronic and electrical equipment of the present invention, the Mg content [Mg] (mass%) and the P content [P] (mass%) are [Mg] + 20 × [P] < It is preferable that the relational expression of 0.5 is satisfied.
In this case, the production | generation of the coarse compound containing Mg and P can be suppressed, and it can suppress that cold work property and bending workability fall.

Moreover, in the copper alloy for electronic / electrical equipment of the present invention, the Mg content [Mg] (mass%) and the P content [P] (mass%) satisfy [Mg] / [P] ≦ 400. It is preferable to satisfy the relational expression.
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 orthogonal to the rolling direction is 300 MPa or more.
In this case, since the 0.2% proof stress at the time of performing a tensile test in a direction orthogonal to the rolling direction is defined as described above, the terminal is not easily deformed, such as a connector or a press fit, It is particularly suitable as a copper alloy for electronic and electrical equipment parts such as movable pieces for relays, lead frames and bus bars.

Moreover, in the copper alloy for electronic / electric equipment of this invention, it is preferable that a residual stress rate is 50% or more at 150 degreeC and 1000 hours.
In this case, since the stress relaxation 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 characterized by comprising the above-mentioned copper alloy for electronic / electrical equipment.
According to the copper alloy sheet 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. It is particularly suitable as a material for electronic and electrical device parts such as connectors, press-fit terminals, relay movable pieces, lead frames, bus bars and the like.
In addition, the copper alloy sheet material for electronic / electrical equipment of the present invention includes a sheet material and a sheet material obtained by winding the sheet material in a coil shape.

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 and electrical equipment parts such as connectors, press-fit terminals, relay movable pieces, lead frames, bus bars, etc. Yes. 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. The electronic / electrical device parts in the present invention include terminals such as connectors and press-fit, movable pieces for relays, lead frames, bus bars and the like. The electronic / electrical device parts with this structure are manufactured using the above-mentioned copper alloy sheet material for electronic / electrical devices, so that they exhibit excellent characteristics even when downsized and thinned. Can do.
Moreover, in the component for electronic / electric equipment of this invention, you may have Sn plating layer or Ag plating layer on the surface. The Sn plating layer and the Ag plating layer may be formed in advance on a copper alloy sheet material for electronic / electric equipment, or may be formed after molding a part for electronic / electric equipment.

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 can exhibit excellent characteristics even when it is downsized and thinned.
Moreover, in the terminal of this invention, you may have Sn plating layer or Ag plating layer on the surface. The Sn plating layer and the Ag plating layer may be formed in advance on a copper alloy sheet material for electronic / electric equipment, or may be formed after the terminal is formed.

The bus bar of the present invention is characterized by comprising the above-described copper alloy sheet material for electronic and electrical equipment.
Since the bus bar having this configuration is manufactured using the above-described copper alloy sheet material for electronic and electrical equipment, it can exhibit excellent characteristics even when it is downsized and thinned.
Moreover, in the bus bar of the present invention, the surface may have a Sn plating layer or an Ag plating layer. The Sn plating layer and the Ag plating layer may be formed in advance on a copper alloy sheet material for electronic / electrical equipment, or may be formed after the bus bar is formed.

The movable piece for relay of the present invention is characterized by comprising the above-described copper alloy sheet material for electronic and electrical equipment.
Since the movable piece for relay having this configuration is manufactured using the above-described copper alloy sheet material for electronic and electrical equipment, it can exhibit excellent characteristics even when it is downsized and thinned. .
Moreover, in the movable piece for relay of this invention, you may have Sn plating layer or Ag plating layer on the surface. The Sn plating layer and the Ag plating layer may be formed in advance on a copper alloy sheet material for electronic / electrical equipment, or may be formed after the movable piece for relay is formed.

  According to the present invention, a copper alloy for electronic and electrical equipment having excellent conductivity and bending workability, a copper alloy sheet material for electronic and electrical equipment, a component for electronic and electrical equipment, a terminal, a bus bar, and a movable for relay A piece can be provided.

It is a flowchart of the manufacturing method of the copper alloy for electronic and electric apparatuses which is this embodiment. It is the photograph and EDX analysis result which show an example of the observation result of the compound in a present Example.

Below, the copper alloy for electronic and electric apparatuses which is one Embodiment of this invention is demonstrated.
The copper alloy for electronic / electrical equipment according to this 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.
Moreover, in the copper alloy for electronic / electrical equipment which is this embodiment, the electrical conductivity exceeds 75% IACS.
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 >. It is as follows.

In addition, in the copper alloy for electronic and electrical equipment according to the present embodiment, the Mg content [Mg] (mass%) and the P content [P] (mass%)
[Mg] + 20 × [P] <0.5
Is satisfied.
Furthermore, in this embodiment, Mg content [Mg] (mass%) and P content [P] (mass%)
[Mg] / [P] ≦ 400
Is satisfied.

Moreover, in the copper alloy for electronic / electric equipment which is this embodiment, the 0.2% yield strength at the time of performing a tensile test in a direction orthogonal to the rolling direction is set to 300 MPa or more. That is, in this embodiment, it is a rolled material of a copper alloy for electronic / electrical equipment, and the 0.2% yield strength when a tensile test is performed in a direction orthogonal to the rolling direction in the final rolling process is as described above. It is defined as follows.
Furthermore, in the copper alloy for electronic / electric equipment according to this embodiment, the residual stress rate is 50% or more at 150 ° C. for 1000 hours.

  Here, the reason why the component composition, the compound, and various characteristics are defined 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 effect of improving strength and stress relaxation resistance without greatly reducing the electrical conductivity by being dissolved in the parent phase of the 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 conductivity is greatly reduced, the viscosity of the molten copper alloy is increased, and castability may be reduced.
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 the stress relaxation resistance, the lower limit of the Mg content is preferably 0.16 mass% or more, more preferably 0.17 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 set to 0.30 mass% or less, and more preferably set to 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 P content is 0.01% by mass or more, a coarse compound having a particle diameter of 0.1 μm or more containing Mg and P is likely to be generated. There is a risk of cracks occurring during inter-processing and bending.
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 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. In order to reliably suppress the formation of a coarse compound, the upper limit of the P content is preferably less than 0.009 mass%, more preferably less than 0.008 mass%, and more preferably 0.0075 mass%. It is preferable to set it as follows, and 0.0050 mass% or less is further preferable.

([Mg] + 20 × [P] <0.5)
As described above, when Mg and P coexist, a compound containing Mg and P is generated.
Here, when the Mg content is [Mg] and the P content is [P], when [Mg] + 20 × [P] is 0.5 or more, Mg and The total amount of P is large, and the compound containing Mg and P is coarsened and distributed with a 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. In addition, in order to reliably suppress the coarsening and densification of the compound and suppress the occurrence of cracks during cold working or bending, [Mg] + 20 × [P] is less than 0.48. Preferably, it is more preferable to set it to less than 0.46. More preferably, it is less than 0.44.

([Mg] / [P] ≦ 400)
Mg is an element that has the effect of increasing the viscosity of the molten copper alloy and lowering the castability. Therefore, in order to reliably improve the castability, it is necessary to optimize the ratio of the contents of Mg and P. There is.
Here, in terms of mass ratio, when Mg content is [Mg] and P content is [P], and [Mg] / [P] is more than 400, There is a possibility that the content is increased and the effect of improving castability by the addition of P is reduced.
From the above, 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, and more preferably 300 or less.
When [Mg] / [P] is excessively low, Mg is consumed as a compound, and there is a possibility that the effect of solid solution of Mg cannot be obtained. In order to suppress the formation of a compound 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] should be 20 or more. Preferably, it exceeds 25, and more preferably.

(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. In particular, since Sn greatly reduces the conductivity, it is preferable that it be less than 50 massppm alone.
Furthermore, since Si, Cr, Ti, Zr, Fe, and Co greatly reduce the electrical conductivity and deteriorate the bending workability due to the formation of the compound, it is preferable that the total amount of these elements is less than 500 massppm.

(Compound containing Mg and P)
In the copper alloy for electronic / electric equipment according to this embodiment, as a result of 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 / μm ^2. It is as follows. If a large amount of these large-sized compounds are present, these compounds serve as starting points for cracking, and the bending workability is greatly deteriorated.

As a result of investigating the structure, when 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, that is, the compound containing Mg and P does not exist or a small amount When it is, favorable bending workability will be obtained.
Furthermore, in order to ensure that the above-described effects are achieved, the average number of compounds containing Mg and P having a particle size of 0.05 μm or more is 0.5 / μm ² or less in the alloy. preferable.

The average number of compounds containing Mg and P was calculated by observing 10 fields of view at a magnification of 50,000 times and a field of view of about 4.8 μm ² using a field emission scanning electron microscope. To do.
In addition, the particle diameter of the compound containing Mg and P is the long diameter of the compound (the length of the straight line that can be drawn the longest in the grains under the condition of not contacting the grain boundary in the middle) and the short diameter (in the direction intersecting with the long diameter at right angles). The average value of the length of the straight line that can be drawn the longest under conditions that do not contact the grain boundary in the middle.
The average number (number density) per unit area of the compound containing Mg and P having a particle size of 0.1 μm or more can be controlled mainly by the casting speed, intermediate heat treatment temperature, and heat treatment time. In order to reduce the average number (number density) per unit area of the compound described above, it can be achieved by setting the casting speed fast and setting the intermediate heat treatment at a high temperature and in a short time. The casting speed and intermediate heat treatment conditions are appropriately selected.

(Conductivity: over 75% IACS)
In the copper alloy for electronic and electrical equipment according to the present embodiment, by setting the electrical conductivity to exceed 75% IACS, electronic and electrical equipment such as connectors, press-fit terminals, relay movable pieces, lead frames, bus bars, etc. It can be used satisfactorily as a service part.
The electrical conductivity is preferably more than 76% IACS, more preferably more than 77% IACS, more preferably more than 78% IACS, and still more preferably more than 80% IACS.

(0.2% proof stress: 300 MPa or more)
In the copper alloy for electronic / electric equipment according to this embodiment, the 0.2% proof stress is set to 300 MPa or more, so that terminals such as connectors and press fits, movable pieces for relays, lead frames, bus bars, etc. It is particularly suitable as a material for equipment parts. In the present embodiment, the 0.2% yield strength when the tensile test is performed in the direction orthogonal to the rolling direction is set to 300 MPa or more.
Here, the 0.2% yield strength described above is preferably 325 MPa or more, and more preferably 350 MPa or more.

(Residual stress ratio: 50% or more)
In the copper alloy for electronic devices according to the present embodiment, as described above, the residual stress rate is set to 50% 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 devices 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 orthogonal to the rolling direction is set to 50% or more at 150 ° C. for 1000 hours.
Here, the above-mentioned residual stress rate is preferably 60% or more at 150 ° C. and 1000 hours, and more preferably 70% or more at 150 ° C. and 1000 hours.

  Next, a manufacturing method of the 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 during 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 copper alloy, the size of the compound containing Mg and P can be made finer by increasing the solidification rate. It becomes. Therefore, the cooling rate of the molten metal is preferably 0.5 ° C./sec or more, more preferably 1 ° C./sec or more, and most preferably 15 ° C./sec or more.

(Homogenization / Solution Step S02)
Next, heat treatment is performed for homogenization and solution of the obtained ingot. In the ingot, there may be an intermetallic compound or the like mainly composed of Cu and Mg generated by Mg segregating and concentrating in the solidification process. 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 / solution solution 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.
In addition, in order to increase the efficiency of roughing and to make the structure uniform, which will be described later, hot working may be performed after the homogenization / solution forming step S02 described above. 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 300 ° C. or higher and 900 ° C. or lower.

(Roughing process S03)
In order to process into a predetermined shape, rough processing is performed. The temperature condition in this roughing step S03 is not particularly limited, but is in the range of −200 ° C. to 200 ° C., which is cold or warm processing for suppressing recrystallization or improving dimensional accuracy. It is preferable to use normal temperature. The processing rate (rolling rate) is preferably 20% or more, and more preferably 30% or more. Moreover, there is no limitation in particular about a processing method, For example, rolling, wire drawing, extrusion, groove rolling, forging, a press, etc. are employable.

(Intermediate heat treatment step S04)
After the rough machining step S03, heat treatment is performed for the purpose of thorough solution treatment, recrystallization structure, or softening for improving workability. The method of heat treatment is not particularly limited, but in order not to increase the particle size of the above-mentioned compound formed by crystallization or the like, a high-temperature, short-time heat treatment step is required. The heat treatment is performed at the following holding temperature, 5 seconds to 1 hour, more preferably 500 ° C. to 900 ° C., and 5 seconds to 30 minutes. Further, heat treatment is performed in a non-oxidizing atmosphere or a reducing atmosphere.
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 S03 and the intermediate heat treatment step S04 may be repeatedly performed.

(Finishing process S05)
Finishing is performed to process the copper material after the intermediate heat treatment step S04 into a predetermined shape. Note that the temperature condition in the finishing step S05 is not particularly limited, but is in the range of −200 ° C. to 200 ° C., which is cold or warm processing to suppress recrystallization or softening. In particular, room temperature is preferable. Further, the processing rate is appropriately selected so as to approximate the final shape, but in order to improve the strength by work hardening in the finishing processing step S05, 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, the processing rate is more preferably 40% or more, and most preferably 60% or more. Further, since the bending workability deteriorates due to the increase of the processing rate, it is preferably made 99% or less.

(Finish heat treatment step S06)
Next, a finishing heat treatment is performed on the plastic workpiece obtained in the finishing step S05 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, and more preferably in the range of 200 ° C. or higher and 700 ° C. or lower. In this finishing heat treatment step S06, it is necessary to set heat treatment conditions (temperature, time, cooling rate) so as to avoid a significant decrease in strength due to recrystallization.
For example, it is preferable to hold at 300 ° C. for about 1 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 using a continuous annealing furnace is preferable from the viewpoint of reducing the manufacturing cost.
Furthermore, the above-described finishing processing step S05 and finishing heat treatment step S06 may be repeated.

  In this way, the copper alloy sheet material for electronic / electrical equipment (the sheet material or the sheet material having the coil shape) is produced according to the present embodiment. The thickness of the copper alloy sheet material for electronic / electric equipment is in the range of 0.05 mm to 3.0 mm, preferably in the range of 0.1 mm to less than 3.0 mm. Yes. If the thickness of the copper alloy strip for electronic and electrical equipment is 0.05mm or less, it is not suitable for use as a conductor in high current applications, and if the thickness exceeds 3.0mm, press punching Processing becomes difficult.

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. At this time, it is preferable that the thickness of the copper alloy sheet material for electronic / electric equipment is 10 to 1000 times the plating layer thickness.
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, Components for electronic and electrical equipment such as relay movable pieces, lead frames, and bus bars are formed.

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%, the viscosity of the molten copper alloy containing Mg can be lowered, and the castability can be improved.
Moreover, in the copper alloy for electronic / electrical equipment which is this embodiment, since the electrical conductivity is over 75% IACS, it can be applied to applications that require high electrical conductivity.

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. Therefore, it becomes possible to mold terminals for complicated shapes such as connectors, movable pieces for relays, parts for electronic and electric devices such as lead frames, and the like.

In addition, in the copper alloy for electronic and electrical devices according to the present embodiment, the Mg content [Mg] (mass%) and the P content [P] (mass%) are [Mg] + 20 × [P]. Since the relational expression of <0.5 is satisfied, the production of coarse compounds of Mg and P can be suppressed, and the deterioration of cold workability and bending workability can be suppressed.
Furthermore, in the copper alloy for electronic / electric equipment according to the present embodiment, the Mg content [Mg] (mass%) and the P content [P] (mass%) are [Mg] / [P] ≦ Since the relational expression of 400 is satisfied, the ratio between the content of Mg that lowers the castability and the content of P that improves the castability is optimized, and the castability is reliably improved by the effect of adding P. be able to.

  Moreover, in the copper alloy for electronic / electric equipment according to the present embodiment, the 0.2% proof stress is 300 MPa or more and the residual stress rate is 50% or more at 150 ° C. for 1000 hours. It has excellent stress relaxation properties and is particularly suitable as a material for electronic and electrical equipment parts such as connectors, press-fit terminals, relay movable pieces, lead frames, bus bars, and the like.

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 parts for electronic and electrical equipment such as terminals such as connectors and press-fit, movable pieces for relays, lead frames, and bus bars.
In addition, when an Sn plating layer or an Ag plating layer is formed on the surface, it is particularly suitable as a material for electronic and electrical equipment parts such as connectors, press-fit terminals, relay movable pieces, lead frames, bus bars, etc. .

  Furthermore, the electronic / electric equipment parts (terminals such as connectors and press-fit, relay movable pieces, lead frames, bus bars, etc.) according to the present embodiment are made of the above-described copper alloy for electronic / electric equipment. Even if the size and thickness are reduced, excellent characteristics can be exhibited.

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 2, 19, and 20 are heat insulating material (isowool) molds, Inventive Examples 21 and 22 are carbon molds, Inventive Examples 1, 3 to 18, 23 to 34, and Comparative Examples 1 to 3 are water-cooled functions. In Comparative Examples 4 and 5, an iron mold with a heater having a heating 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, and the ingot was cut out and the size was adjusted so that the thickness of the final product was 0.5 mm.
The block was heated in an Ar gas atmosphere for 4 hours under the temperature conditions shown in Table 2 to perform homogenization / solution treatment.

Then, after carrying out rough rolling on the conditions described in Table 2, it heat-processed on the temperature conditions described in Table 2 using the 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. Thereafter, finish rolling (finishing) was performed at room temperature at a rolling rate described 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 create a thin plate for property evaluation.

(Castability)
As an evaluation of castability, the presence or absence of rough skin at the time of casting was observed. The case where no or almost no skin roughness was visually observed was indicated by ◎, the case where a small skin roughness less than 1 mm in depth occurred was indicated by ◯, and the case where skin roughness was caused 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 made into x, and evaluation was stopped on the way. The evaluation results are shown in Table 3.
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.

(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) with a 10,000 × field of view (approximately 120 μm ² / field of view).
Next, in order to investigate the density of the compound containing Mg and P (pieces / μm ² ), a field of view of 10,000 times (about 120 μm ² / field of view) was selected, and 10 × The field of view (about 4.8 μm ² / field of view) was photographed. 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. An example of the observation results of the compound is shown in FIG.

(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. In addition, the test piece was extract | collected in the direction orthogonal to a 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 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 become perpendicular | vertical with respect to the rolling direction of the strip for characteristic evaluation. The evaluation results are shown in Table 3.

(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. . The evaluation results are shown in Table 3.
As a test method, a specimen (width 10 mm) is taken from each characteristic evaluation strip in a direction orthogonal to the rolling direction, and the initial deflection displacement is set so that the maximum surface stress of the specimen is 80% of the proof stress. The span length was adjusted to 2 mm. 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 sample (t = 0.5 mm)
δ ₀ : Initial deflection displacement (2 mm)
L _s : Span length (mm)
It is.
The 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 at 150 ° C. for 1000 hours (mm) −Permanent deflection displacement after holding for 24 h at room temperature (mm)
δ ₀ : Initial deflection displacement (mm)
It is.

(Bending workability)
Bending was performed in accordance with four test methods of Japan Copper and Brass Association Technical Standard JCBA-T307: 2007. A plurality of test pieces having a width of 10 mm and a length of 30 mm are taken from the thin sheet for characteristic evaluation so that the bending axis is perpendicular to the rolling direction, the bending angle is 90 degrees, the bending radius is a finish rolling ratio of 85. W-type jigs having a bending radius of 0.3 mm (R / t = 0.6) when the rolling reduction ratio is 85% or less. A W-bending test was performed.
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.

In Comparative Example 1, the Mg content was less than the range of the present invention, and the proof stress and the stress relaxation resistance were insufficient.
In Comparative Example 2, the Mg content was larger than the range of the present invention, and the conductivity was low.
In Comparative Example 3, the P content was larger than the range of the present invention, and cracking occurred in the intermediate rolling, and evaluation could not be performed.
In Comparative Examples 4 and 5, the contents of Mg and P were large, and the cooling rate at the time of casting was slow, so there were many compounds and the bending workability was poor.

On the other hand, in the examples of the present invention, it is confirmed that the castability, strength (0.2% yield strength), electrical conductivity, stress relaxation resistance (residual stress rate), and bending workability are excellent.
From the above, it was confirmed that according to the examples of the present invention, it is possible to provide a copper alloy for electronic / electric equipment and a copper alloy sheet material for electronic / electric equipment excellent in conductivity and bending workability.

Claims (15)

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,
The conductivity is over 75% IACS,
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 . Mg content [Mg] (mass%) and P content [P] (mass%)
[Mg] + 20 × [P] <0.5
The copper alloy for electronic and electrical equipment according to claim 1, wherein the following relational expression is satisfied. Mg content [Mg] (mass%) and P content [P] (mass%)
[Mg] / [P] ≦ 400
The copper alloy for electronic / electric equipment according to claim 1, wherein the following relational expression is satisfied.   4. The electronic / electric device according to claim 1, wherein a 0.2% yield strength when a tensile test is performed in a direction orthogonal to a rolling direction is 300 MPa or more. 5. Copper alloy.   The copper alloy for electronic / electric equipment according to any one of claims 1 to 4, wherein the residual stress rate is 50% or more at 1000C for 1000 hours.   A copper alloy sheet material for electronic and electrical equipment, comprising the copper alloy for electronic and electrical equipment according to any one of claims 1 to 5.   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.   The component for electronic / electric equipment according to claim 8, comprising a Sn plating layer or an Ag plating layer on the surface.   A terminal comprising the copper alloy sheet material for electronic / electrical equipment according to claim 6 or 7.   The terminal according to claim 10, comprising a Sn plating layer or an Ag plating layer on the surface.   A bus bar comprising the copper alloy sheet material for electronic / electrical equipment according to claim 6 or 7.   The bus bar according to claim 12, comprising a Sn plating layer or an Ag plating layer on a surface thereof.   A movable piece for a relay comprising the copper alloy sheet material for electronic / electrical equipment according to claim 6 or 7.   The movable piece for a relay according to claim 14, comprising a Sn plating layer or an Ag plating layer on a surface thereof.