TWI703225B - Copper alloy for electronic/electric device, copper alloy sheet or strip for electronic/electric device, component for electronic/electric device, terminal, bus bar, and movable piece for relay - Google Patents

Abstract

The copper alloy includes: 0.15 mass% or more and less than 0.35 mass% of Mg; 0.0005 mass% or more and less than 0.01 mass% of P; and the Cu balance containing inevitable impurities, wherein the conductivity exceeds 75%IACS, the average number of particles of Mg-P-containing compound having the grain size of 0.1 μm or more is 0.5 particle/μm² in observation by the scanning electron microscope.

Description

Copper alloys for electronic and electrical equipment, copper alloy plates and strips for electronic and electrical equipment, parts for electronic and electrical equipment, terminals, bus bars, and movable pieces for relay

The invention relates to electronics suitable for terminals, lead frames, bus bars, movable pieces for relays, etc., such as connectors or press-fitting. Electronic parts for electrical machinery. Copper alloys for electrical equipment, and the electronics. Electronics made of copper alloy for electrical equipment. Copper alloy sheet and strip for electrical equipment, electronics. Electrical equipment parts, terminals, bus bars, and movable pieces for relays.

This application is based on Japanese Patent Application No. 2016-069080 filed in Japan on March 30, 2016 and Japanese Patent Application No. 2017-063418 filed in Japan on March 28, 2017, and the content is quoted In this article.

In the past, terminals and relays such as connectors or press-fitting Electronics such as movable pieces, lead frames, bus bars, etc. The parts for electrical equipment use copper or copper alloys with high conductivity.

Here, with the miniaturization of electronic equipment or electrical equipment, the electronics used in such electronic equipment or electrical equipment has also been realized. Miniaturization and thinning of electrical equipment parts. Therefore, the pair constitutes electrons. The materials of electrical equipment parts require high strength and good bending workability. In addition, the terminals of connectors used in high-temperature environments such as the engine room of automobiles are also required to withstand stress relaxation characteristics.

Used as a connector or press-fit terminal, movable piece for relay, lead frame, bus bar, etc. As materials used for parts for electrical equipment, Cu-Mg alloys are proposed in Patent Documents 1 and 2, for example.

[Prior technical literature] 〔Patent Literature〕

[Patent Document 1] Japanese Patent No. 5045783 (B)

[Patent Document 2] JP 2014-114464 A (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 it to applications requiring high conductivity.

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%. Considering the coarse compound that greatly deteriorates cold workability and bending workability, cold workability and bending workability are insufficient.

Furthermore, in the above-mentioned Cu-Mg-based alloy, the molten bath viscosity of the copper alloy increases due to Mg. Therefore, when P is not added, there is a problem that the castability decreases.

And, recently, with the electronic. Lightweight electrical equipment, and realize the electronic equipment such as terminals, relay movable pieces, lead frames, etc. used in such electronic equipment or electrical equipment. Thinning of electrical equipment parts. Therefore, in order to ensure crimping, it is necessary to perform strict bending processing in terminals such as connectors, and bending processing properties are required to be increased more than before.

In view of the foregoing, the present invention aims to provide electronics with excellent conductivity and bending workability. Copper alloys for electrical equipment, electronics. Copper alloy sheet and strip for electrical equipment, electronics. Parts for electrical equipment, terminals, bus bars, and movable pieces for relays.

In order to solve this problem, the present invention is the same state of electron. The copper alloy for electrical equipment (hereinafter referred to as "the copper alloy for electronic and electrical equipment of the present invention") is characterized by containing Mg in the range of 0.15 mass% or more and less than 0.35 mass%, and 0.0005 mass% or more. Contain P within the range of 0.01 mass%, the rest is made of Cu and unavoidable impurities, and the conductivity exceeds 75% IACS, and in the scanning electron microscope observation, the compound containing Mg and P with a particle size of 0.1 μm or more The average number of particles is 0.5/μm ² or less.

Based on the above composition of the electronics. For copper alloys for electrical equipment, since the Mg content is set to 0.15mass% or more and less than 0.35mass%, Mg is solid-melted in the mother phase of copper, so the electrical conductivity is not greatly reduced, but the strength and stress resistance can be improved. Relaxation characteristics. Specifically, since the conductivity exceeds 75% IACS, it can also be applied to applications requiring high conductivity. In addition, since P is contained within 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 reduced, and the castability can be improved.

In addition, in scanning electron microscope observation, the average number of compounds containing Mg and P with a particle size of 0.1 μm or more is 0.5/μm ² or less. Therefore, in the matrix, the coarse starting point of cracking contains Mg and P Since most of the compounds are not dispersed, the bending workability improves. Therefore, it is possible to form complex-shaped connectors such as terminals, relay movable pieces, lead frames and other electronics. Parts for electrical equipment, etc.

Here, the electronics of the present invention. In copper alloys for electrical equipment, preferably the content of Mg [Mg] (mass%) and the content of P [P] (mass%) satisfy the following relationship: [Mg]+20×[P]<0.5.

In this case, the generation of coarse compounds containing Mg and P can be suppressed, and the decrease in cold workability and bending workability can be suppressed.

And, the electronics of the present invention. In copper alloys for electrical equipment, it is preferable that the content of Mg [Mg] (mass%) and the content of P [P] (mass%) satisfy the following relationship: [Mg]/[P]≦400.

In this case, the ratio of the Mg content for reducing the castability to the P content for improving the castability is determined as described above, and the castability can be reliably improved.

Furthermore, the electronics of the present invention. In the copper alloy for electrical equipment, it is preferable that the 0.2% endurance at the time of tensile test in the direction orthogonal to the rolling direction is 300 MPa or more.

In this case, since the 0.2% endurance during the tensile test in the direction orthogonal to the rolling direction is specified as described above, it is not easy to deform, and it is particularly suitable as a connector, a press-fitting terminal, and a movable piece for relay. , Lead frame, bus bar and other electronics. Copper alloy for electrical machinery parts.

Also, the electronics of the present invention. In copper alloys for electrical equipment, the residual stress rate is preferably 50% or more at 150°C for 1000 hours.

In this case, since the stress relaxation rate is determined as described above, the permanent deformation can be suppressed to be small even when used in a high-temperature environment. For example, it is possible to suppress reduction in crimping of connector terminals and the like. Therefore, it can be used as a material for parts of electronic equipment used in high-temperature environments such as engine rooms.

Other types of electrons of the present invention. Copper alloy sheet and strip for electrical equipment (hereinafter referred to as "electronics of the present invention. Copper alloy sheet and strip for electrical equipment"), which are characterized by the above-mentioned electronic. Made of copper alloy for electrical equipment.

Based on the structure of the electronics. Copper alloy plates and strips for electrical equipment, due to the above-mentioned electronics. Electrical equipment is made of copper alloy, so it has excellent electrical conductivity, strength, bending workability, and stress relaxation properties. It is especially suitable for terminals such as connectors or press-fitting, movable pieces for relays, lead frames, bus bars, etc. electronic. Materials for parts of electrical machinery.

Also, the electronics of the present invention. Copper alloy slabs and strips for electrical equipment are strips that include plates that are coiled into coils.

Here, the electronics of the present invention. In the copper alloy plate and strip for electrical equipment, it is preferable that the surface has a Sn plating layer or an Ag plating layer.

In this case, due to the Sn plating layer or Ag plating layer on the surface, it is particularly suitable as a connector or press-fit terminal, relay movable piece, lead frame, bus bar and other electronics. Materials for parts of electrical machinery. Moreover, 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.

Other types of electrons of the present invention. Parts for electrical equipment (hereinafter referred to as "parts for electronic and electrical equipment of the present invention") are characterized by the aforementioned electronics. It is made of copper alloy plate and strip for electrical equipment. Also, the electronics of the present invention. Parts for electrical equipment include connectors or press-fit terminals, movable pieces for relays, lead frames, bus bars, etc. The composition of the electronics. The parts for electrical machinery use the above-mentioned electronics. Electrical equipment is made of copper alloy slabs, so it can exhibit excellent characteristics even in miniaturization and thinning.

Also, the electronics of the present invention. In the parts for electrical equipment, the surface may have a Sn plating layer or an Ag plating layer. In addition, the Sn plating layer and Ag plating layer can also be pre-formed on the electronics. Copper alloy plates and strips for electrical machines can also be used in forming electronics. After forming parts for electrical equipment.

Another aspect of the terminal of the present invention (hereinafter referred to as "the terminal of the present invention") is characterized by the above-mentioned electronic. It is made of copper alloy plate and strip for electrical equipment.

The terminal of this structure uses the above-mentioned electrons. Electrical equipment is made of copper alloy sheet and strip, so it can be used even in miniaturization and thinning Excellent characteristics.

Moreover, in the terminal of the present invention, the surface may have a Sn plating layer or an Ag plating layer. In addition, the Sn plating layer and Ag plating layer can also be pre-formed on the electronics. Copper alloy plates and strips for electrical equipment can also be formed after forming terminals.

Another aspect of the bus bar of the present invention (hereinafter referred to as "the bus bar of the present invention") is characterized by the above-mentioned electronic. It is made of copper alloy plate and strip for electrical equipment.

The bus bar of this structure uses the above-mentioned electronics. Electrical equipment is made of copper alloy slabs, so it can exhibit excellent characteristics even in miniaturization and thinning.

Furthermore, in the bus bar of the present invention, the surface may have a Sn plating layer or an Ag plating layer. In addition, the Sn plating layer and Ag plating layer can also be pre-formed on the electronics. Copper alloy plates and strips for electrical equipment can also be formed after bus bars are formed.

Another aspect of the movable piece for relaying of the present invention (hereinafter referred to as the "movable piece for relaying of the present invention") is characterized by the above-mentioned electronic. It is made of copper alloy plate and strip for electrical equipment.

The movable piece for relay of this structure uses the above-mentioned electronics. Electrical equipment is made of copper alloy slabs, so it can exhibit excellent characteristics even in miniaturization and thinning.

In addition, the movable piece for relay of the present invention may have a Sn plating layer or an Ag plating layer on the surface. In addition, the Sn plating layer and Ag plating layer can also be pre-formed on the electronics. Copper alloy plates and strips for electrical equipment can also be formed after forming movable pieces for relay.

According to the present invention, it is possible to provide electronics with excellent conductivity and bending workability. Copper alloys for electrical equipment, electronics. Copper alloy sheet and strip for electrical equipment, electronics. Parts for electrical equipment, terminals, bus bars, and movable pieces for relays.

Figure 1 shows the electronics of this embodiment. Flow chart of the manufacturing method of copper alloy for electrical equipment.

Fig. 2A is a photograph showing an example of the observation result of the compound of this example.

Figure 2B shows an example of the EDX analysis result of the compound of this example.

Hereinafter, for the electronics of one embodiment of the present invention. Copper alloys are used to illustrate electrical equipment.

The electronics of this embodiment. The copper alloy for electrical equipment has the following composition: 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 rest is made of Cu and unavoidable Made by impurities.

Also, the electronics of this embodiment. Conductive in copper alloys for electrical equipment The rate exceeds 75% IACS.

Moreover, the electronics of this embodiment. In the copper alloy for electrical equipment, the average number of compounds containing Mg and P with a particle size of 0.1 μm or more in the observation with a scanning electron microscope is 0.5 pieces/μm ² or less.

Also, the electronics of this embodiment. In copper alloys for electrical equipment, the content of Mg [Mg] (mass%) and the content of P [P] (mass%) satisfy the following relationship:

[Mg]+20×[P]<0.5.

Furthermore, in this embodiment, the content of Mg [Mg] (mass%) and the content of P [P] (mass%) satisfy the following relationship: [Mg]/[P]≦400.

Also, the electronics of this embodiment. In the copper alloy for electrical equipment, the 0.2% endurance at the time of the tensile test in the direction orthogonal to the rolling direction is 300 MPa or more. In other words, in this embodiment, electronic components are made. The 0.2% endurance of the rolled copper alloy for electrical equipment during the tensile test in the direction orthogonal to the rolling direction in the final step of rolling is specified as above.

Furthermore, the electronics of this embodiment. In copper alloys for electrical equipment, the residual stress rate is 50% or more at 150°C for 1000 hours.

Here, the reasons for defining the above-mentioned component composition, compound, and various characteristics are explained as follows.

(Mg: 0.15mass% or more, less than 0.35mass%)

Mg is solid melted in the mother phase of copper alloy without causing conductivity It is greatly reduced and has the effect of improving the strength and resistance to stress relaxation.

Here, if the Mg content is less than 0.15 mass%, there is a possibility that the effect cannot be fully exhibited. On the other hand, when the Mg content is 0.35 mass% or more, the electrical conductivity is greatly reduced and the viscosity of the copper alloy molten bath increases, which may reduce the castability.

Based on the above, in this embodiment, the Mg content is set to be within a range of 0.15 mass% or more and less than 0.35 mass%.

Moreover, in order to further improve the strength and the stress relaxation resistance, the lower limit of the Mg content is preferably set to 0.16 mass% or more, and more preferably set to 0.17 mass% or more. In addition, in order to surely suppress the decrease in electrical 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: 0.0005mass% or more, less than 0.01mass%)

P is an element that has the effect of improving castability.

Here, if the P content is less than 0.0005 mass%, the effect may not be fully exhibited. On the other hand, when the P content is 0.01 mass% or more, since it is easy to produce coarse compounds containing Mg and P with a particle size of 0.1 μm or more, this compound may be used as a starting point for damage, and cracks may occur during cold working or bending. .

Based on the above, in the present embodiment, the P content is set within the range of 0.0005 mass% or more and less than 0.01 mass%. In addition, in order to surely improve the castability, the lower limit of the P content is preferably 0.0007 mass% or more It is better to be 0.001 mass% or more. In addition, in order to surely suppress the formation of coarse compounds, the upper limit of the P content is preferably less than 0.009 mass%, more preferably less than 0.008 mass%, still more preferably 0.0075 mass% or less, and still more preferably 0.0050 mass% or less.

([Mg]+20×[P]<0.5)

As mentioned above, by the coexistence of Mg and P, a compound containing Mg and P is generated.

Here, when the content of Mg [Mg] and the content of P [P] are set in terms of mass ratio, when [Mg]+20×[P] is 0.5 or more, the total amount of Mg and P is large and contains Mg The compound of P and P is coarsened and distributed in high density, and it is likely to produce cracks during cold working or bending.

Based on the above, in this embodiment, [Mg]+20×[P] is set to less than 0.5. In addition, in order to surely suppress the coarsening and high density distribution of the compound, and to suppress the occurrence of cracks during cold working or bending, it is preferable to set [Mg]+20×[P] to less than 0.48, more preferably less than 0.46 . It is better than 0.44.

([Mg]/[P]≦400)

Since Mg is an element that has the effect of increasing the viscosity of the copper alloy bath and reducing the castability, it is necessary to make the content of Mg and P appropriate in order to surely improve the castability.

Here, when the content of Mg [Mg] and the content of P [P] are set in terms of mass ratio, when [Mg]/[P] exceeds 400, the Mg content will increase relative to P. The castability improvement effect due to the addition of P may be reduced.

Based on the above, in this embodiment, [Mg]/[P] is set to 400 or less. In order to further improve the castability, [Mg]/[P] is preferably at most 350, more preferably at most 300.

In addition, when [Mg]/[P] is too low, Mg is consumed as a compound, and there is a possibility that the effect due to the solid solution of Mg cannot be obtained. In order to inhibit the formation of compounds containing Mg and P, and to achieve the improvement of endurance and stress relaxation resistance properties caused by the solid melting of Mg, it is preferable that the lower limit of [Mg]/[P] exceeds 20, and more preferably exceeds 25.

(Inevitable impurities: 0.1mass% or less)

As other unavoidable impurities, for example, 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, etc. These unavoidable impurities have the effect of reducing the conductivity, so the total amount is less than 0.1 mass%.

In addition, since Ag, Zn, and Sn are easily mixed into copper to lower the conductivity, the total amount is preferably less than 500 mass ppm. In particular, Sn greatly reduces the conductivity, so it is preferably less than 50 massppm alone.

Furthermore, Si, Cr, Ti, Zr, Fe, and Co in particular can greatly reduce electrical conductivity and degrade bending workability due to the formation of compounds. Therefore, the total amount of these elements is preferably less than 500 massppm.

(Compounds containing Mg and P)

The electronics of this embodiment. In the copper alloy for electrical equipment, the average number of compounds containing Mg and P with a particle size of 0.1 μm or more in the observation with a scanning electron microscope is 0.5 pieces/μm ² or less. If these large-size compounds are present in large amounts, these compounds will become the starting point of cracks, which greatly deteriorates the bending workability.

As a result of tissue investigation, when the average number of compounds containing Mg and P with a particle size of 0.1 μm or more is 0.5/μm ² or less, that is, when there is no or a small amount of compounds containing Mg and P, good bending is obtained Processability.

Furthermore, in order to ensure the above-mentioned effects, it is preferable that the average number of compounds containing Mg and P with a particle size of 0.05 μm or more in the alloy is 0.5 pieces/μm ² or less.

In addition, the average number of compounds containing Mg and P was observed using a field emission scanning electron microscope at a magnification of 50,000 times and a field of view: approximately 4.8 μm ² and the average value was calculated.

And, the particle size of the compound containing Mg and P is set as the long diameter of the compound (the length of the longest straight line drawn in the grain under the condition that the period is not tangent to the grain boundary) and the short diameter (when it intersects with the long diameter at right angles). The average value of the length of the longest straight line drawn under the condition that the period is not tangent to the grain boundary). The average number per unit area (number density) of compounds containing Mg and P with a particle size of 0.1 μm or more can be controlled mainly by casting speed, intermediate heat treatment temperature, and heat treatment time. In order to reduce the above compound per unit area The average number (number density) can be achieved by setting the casting speed to fast and the intermediate heat treatment to high temperature and short time. The casting speed and intermediate heat treatment conditions are appropriately selected.

(Conductivity: more than 75%IACS)

The electronics of this embodiment. In the copper alloy for electrical equipment, by setting the conductivity to exceed 75% IACS, it can be used well as electronics such as connectors, press-fit terminals, movable pieces for relays, lead frames, and bus bars. Parts for electrical equipment.

In addition, the conductivity preferably exceeds 76% IACS, more preferably exceeds 77% IACS, still more preferably exceeds 78% IACS, and still more preferably exceeds 80% IACS.

(0.2% endurance: above 300MPa)

The electronics of this embodiment. Among the copper alloys for electrical equipment, by setting the 0.2% endurance to 300 MPa or more, it is particularly suitable for use as connectors, press-fit terminals, movable pieces for relays, lead frames, and bus bars. Materials for parts of electrical machinery. In addition, in this embodiment, the 0.2% resistance when the tensile test is performed in the direction orthogonal to the rolling direction is set to 300 MPa or more.

Here, the aforementioned 0.2% endurance is preferably 325 MPa or more, more preferably 350 MPa or more.

(Residual stress rate: more than 50%)

The electronics of this embodiment. In the copper alloy for electrical equipment, 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 this condition is high, even when used in a high-temperature environment, the permanent deformation can be suppressed to be small, and the reduction of the crimping can be suppressed. Therefore, the copper alloy for electronic equipment of this embodiment can be suitably used as a terminal for use in a high-temperature environment around the engine room of an automobile. In this embodiment, the residual stress rate when the stress relaxation test is performed 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 ratio is preferably at least 60% at 150°C and 1000 hours, and more preferably at least 70% at 150°C and 1000 hours.

Hereinafter, for the electronics of this embodiment constructed in this way. The manufacturing method of the copper alloy for electrical equipment is described with reference to the flowchart shown in Figure 1.

(Melting. Casting step S01)

First, in the copper molten bath obtained by melting the copper raw materials, the aforementioned elements are added to adjust the composition to prepare a copper alloy molten bath. In addition, for the addition of various elements, a single element or a master alloy can be used. In addition, a raw material containing the above-mentioned elements may be used as a copper raw material and melted. In addition, recycled materials and scrap materials of this alloy can also be used. Here, the copper molten bath is preferably a so-called 4NCu with a purity of 99.99 mass% or more or a so-called 5NCu with a purity of 99.999 mass% or more. In the melting step, in order to suppress the oxidation of Mg and to reduce the hydrogen concentration, it is preferable to perform environmental melting in an inert environment with a low vapor pressure of H ₂ O (for example, Ar gas), and the retention time during melting is preferably limited to a minimum.

Then, the copper alloy molten bath whose composition has been adjusted is injected into the mold to produce an ingot. In addition, when considering mass production, it is preferable to use a continuous casting method or a semi-continuous casting method.

At this time, when the molten bath solidifies, the compound containing Mg and P is formed as a crystallization product. Therefore, by increasing the solidification rate, the size of the compound containing Mg and P can be made finer. Therefore, the cooling rate of the molten bath is preferably 0.5°C/sec or more, more preferably 1°C/sec or more, most preferably 15°C/sec or more.

(Homogenization/meltization step S02)

Next, heat treatment is performed in order to homogenize and melt the obtained ingot. Inside the ingot, there are intermetallic compounds with Cu and Mg as the main components that occur due to the segregation and concentration of Mg during the solidification process. Therefore, in order to make the segregation and intermetallic compounds disappear or reduce, the ingot is heated to 300°C or more and 900°C or less by heating treatment, so that Mg is uniformly diffused in the ingot, and the Mg is solidified. In the mother phase. In addition, the homogenization/melting step S02 is preferably carried out in a non-oxidizing or reducing environment.

Here, if the heating temperature does not reach 300°C, the melt will be incomplete, and there is a possibility that a large amount of intermetallic compounds mainly composed of Cu and Mg will remain in the mother 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 or surface state may become uneven. Therefore, the heating temperature is set in the range of 300°C or more and 900°C or less.

In addition, in order to increase the efficiency of rough processing and homogenize the structure described later, hot working may be performed after the homogenization/melting step S02 described above. This situation, The processing method is not particularly limited, and, for example, rolling, drawing, extrusion, groove rolling, forging, pressing, etc. can be used. In addition, the hot working temperature is preferably within a range of 300°C or more and 900°C or less.

(Rough machining step S03)

Rough machining is performed for processing into a specific shape. In addition, the temperature conditions in the rough processing step S03 are not particularly limited, but in order to suppress recrystallization or to improve dimensional accuracy, it is preferably in the range of -200°C to 200°C for cold working or warm working, and particularly preferably Room temperature. Regarding the processing rate (rolling rate), it is preferably 20% or more, more preferably 30% or more. The processing method is not particularly limited, and for example, rolling, drawing, extrusion, groove rolling, forging, pressing, etc. can be used.

(Intermediate heat treatment step S04)

After the rough processing step S03, heat treatment is performed for the purpose of complete melting, recrystallization, or softening for improving workability. The heat treatment method is not particularly limited, but in order not to increase the particle size of the above-mentioned compound formed by crystallization, etc., a high temperature and short time heat treatment step is necessary, so it is preferably maintained at 400°C or higher and 900°C or lower Heat treatment at a temperature, a holding time of 5 seconds or more and 1 hour or less, more preferably a holding temperature of 500°C or more and 900°C or less, and a holding time of 5 seconds or more and 30 minutes or less. And heat treatment in non-oxidizing environment or reducing environment.

In addition, the cooling method after heating is not particularly limited, but it is preferable to use a method in which the cooling rate such as water quenching is 200°C/min or more.

In addition, the rough machining step S03 and the intermediate heat treatment step S04 may be repeatedly implemented.

(Finishing step S05)

In order to process the copper material after the intermediate heat treatment step S04 into a specific shape, finishing processing is performed. In addition, the temperature conditions in the finishing step S05 are not particularly limited, but in order to suppress recrystallization, or to suppress softening, it is preferably in the range of -200°C to 200°C for cold working or warm working, and particularly preferred For normal temperature. In addition, although the processing rate is appropriately selected to approximate the final shape, in order to increase the strength by work hardening in the finishing step S05, the processing rate is preferably 20% or more. When the strength is further improved, the processing rate is preferably set to 30% or more, and the processing rate is more preferably set to 40% or more, preferably 60% or more. In addition, the increase in the processing rate deteriorates the bending workability, so it is preferably set to 99% or less.

(Finishing heat treatment step S06)

Next, for the plastic processed material obtained in the finishing process step S05, finishing heat treatment is performed in order to improve the stress relaxation resistance and low-temperature burnt hardening, and to remove residual deformation.

The heat treatment temperature is preferably within a range of from 100°C to 800°C, more preferably within a range of from 200°C to 700°C. In addition, in this finishing heat treatment step S06, it is necessary to set the heat treatment conditions (temperature, time, cooling rate) in order to avoid a method of greatly reducing the strength due to recrystallization.

For example, it is preferable to maintain at 300°C for about 1 second to 120 seconds. This heat treatment is preferably performed in a non-oxidizing environment or a reducing environment.

The heat treatment method is not particularly limited, but based on the effect of reducing the manufacturing cost, a short-time heat treatment using a continuous bake furnace is preferred.

Furthermore, the finishing step S05 and finishing heat treatment step S06 described above can also be repeated.

In this way, the electronics of this embodiment is produced. Copper alloy strips for electrical equipment (plates or strips made into coils). Also, the electronic. The thickness of the copper alloy sheet material for electrical equipment is set to be in the range of more than 0.05 mm and 3.0 mm or less, preferably in the range of more than 0.1 mm and less than 3.0 mm. electronic. When the thickness of the copper alloy sheet and strip for electrical equipment is less than 0.05mm, it is not conducive to use as a conductor for large current applications. When the thickness exceeds 3.0mm, it is difficult to press and press.

Here, the electronics of this embodiment. Copper alloy plates and strips for electrical equipment can be used directly in electronics. For electrical equipment parts, it is also possible to form a Sn plating layer or Ag plating layer with a film thickness of about 0.1-100μm on one or both sides of the board. At this time, electronic. The thickness of the copper alloy sheet and strip for electrical equipment is preferably 10 to 1000 times the thickness of the plating layer.

Furthermore, by combining the electronics of this embodiment. Copper alloy for electrical equipment (copper alloy plate and strip for electronic and electrical equipment) is used as a material, which can be formed by pressing or bending, etc., and forming terminals such as connectors or press-fitting, movable pieces for relays, and lead frames , The electronics of the bus bar. Parts for electrical equipment.

Based on the electronics of this embodiment constructed as above. electric For copper alloys for machinery, the Mg content is set to be above 0.15mass% but not within the range of 0.35mass%. Therefore, by solid melting of Mg in the mother phase of copper, the electrical conductivity can be improved and the strength and resistance can be improved. Stress relaxation characteristics. In addition, since P is set to be within the range of 0.0005 mass% or more and less than 0.01 mass%, the molten bath viscosity of the copper alloy containing Mg can be reduced, and the castability can be improved.

And, the electronics of this embodiment. In copper alloys for electrical equipment, since the conductivity is set to exceed 75% IACS, it can also be applied to applications requiring high conductivity.

Moreover, the electronics of this embodiment. In copper alloys for electrical equipment, the average number of compounds containing Mg and P with a particle size of 0.1μm or more is set to 0.5/μm ² or less in the scanning electron microscope observation, so there are not many in the matrix Disperse the coarse Mg and P-containing compounds that become the starting point of cracks to improve bending workability. Therefore, it is possible to form complex-shaped connectors such as terminals, relay movable pieces, lead frames and other electronics. Parts for electrical equipment.

Also, the electronics of this embodiment. In copper alloys for electrical equipment, since the content of Mg [Mg] (mass%) and the content of P [P] (mass%) satisfy the relational expression of [Mg]+20×[P]<0.5, it can suppress Mg and The formation of coarse compounds of P can suppress the decrease in cold workability and bending workability.

Furthermore, the electronics of this embodiment. In copper alloys for electrical equipment, since the content of Mg [Mg] (mass%) and the content of P [P] (mass%) satisfy the relational expression of [Mg]/[P]≦400, Mg which reduces the castability content The ratio of the content of P to improve the castability is appropriate, and the castability can be reliably improved by the effect of adding P.

Also, the electronics of this embodiment. In the copper alloy for electrical equipment, the 0.2% endurance is set to 300 MPa or more, and the residual stress rate is set to 50% or more at 150°C and 1000 hours. Therefore, it has excellent strength and stress relaxation characteristics, and is particularly suitable for connectors or press-fitting. The terminal, relay movable piece, lead frame, bus bar and other electronics. Materials for parts of electrical machinery.

Also, the electronics of this embodiment. Copper alloy plates and strips for electrical equipment are based on the above-mentioned electronics. The electrical equipment is made of copper alloy, so by the electronic. Copper alloy plates and strips for electrical equipment are used for bending processing, etc., and can be used to manufacture connectors or press-fit terminals, movable pieces for relays, lead frames, bus bars and other electronics. Parts for electrical equipment.

In addition, when the Sn plating layer or Ag plating layer is formed on the surface, it is particularly suitable as a connector or press-fit terminal, a movable piece for relay, a lead frame, a bus bar, etc. Materials for parts of electrical machinery.

Furthermore, the electronics of this embodiment. Parts for electrical equipment (connectors or press-fit terminals, movable pieces for relays, lead frames, bus bars, etc.) are based on the above-mentioned electronics. The electrical equipment is made of copper alloy, so even if it is miniaturized and thinned, it can exhibit excellent characteristics.

Although the above is for the electronics of the embodiment of the present invention. Copper alloys for electrical equipment, electronics. Copper alloy sheet and strip for electrical equipment, electronics. Parts for electrical equipment (terminals, bus bars, etc.) are described, but the present invention is not limited to these, and can be appropriately changed without departing from the technical idea of the present invention more.

For example, the above embodiment is aimed at electronics. An example of the manufacturing method of copper alloy for electrical equipment is explained, but electronic. The manufacturing method of the copper alloy for electrical equipment is not limited to those described in the embodiment, and an existing manufacturing method may be appropriately selected.

[Example]

Hereinafter, the results of confirmation experiments performed to confirm the effects of the present invention will be described.

Prepare a copper raw material made of oxygen-free copper (ASTM B152 C10100) with a purity of 99.99 mass% or more, put it into a high-purity graphite crucible, and conduct high-frequency melting in an environmental furnace set in an Ar atmosphere. In the obtained copper molten bath, various additional elements are added to prepare the composition shown in Table 1, and the liquid is poured into the casting mold to form an ingot. In addition, examples 2, 19, and 20 of the present invention use heat insulating material (ISOWOOL) molds, examples 21 and 22 of the present invention use carbon molds, examples 1, 3 to 18, 23 to 34 of the present invention, and comparative examples 1 to 3 A copper alloy mold with water cooling function was used. Comparative Examples 4 and 5 used iron molds with a heater with heating function as casting molds. The size of the ingot is set to be about 100 mm thick × about 150 mm wide × about 300 mm long.

Surface grinding near the casting surface of the ingot, cut out the ingot and adjust the size so that the thickness of the final product is 0.5mm.

The block was heated in an Ar gas atmosphere under the temperature conditions described in Table 2 for 4 hours to perform homogenization/melting treatment.

Subsequently, after rough rolling was performed under the conditions described in Table 2, the Heat treatment in a salt bath under the temperature conditions described in Table 2.

The heat-treated copper material is cut in order to be suitable for the final shape, and the surface is ground to remove the oxide film. Subsequently, finishing rolling (finishing processing) was performed at room temperature at the rolling rate described in Table 2 to produce a thin plate with a thickness of 0.5 mm, a width of about 150 mm, and a length of 200 mm.

Next, after finishing rolling (finishing processing), finishing heat treatment was performed in an Ar environment under the conditions shown in Table 2, and then water quenching was performed to produce a sheet for characteristic evaluation.

(Castability)

As the castability evaluation, the presence or absence of surface roughness during the aforementioned casting was observed. If the surface roughness is almost completely unobserved by visual inspection, it is recorded as A, the small surface roughness with a depth of less than 1mm is recorded as B, and the surface roughness with a depth of 1mm or more and less than 2mm is recorded as C. And the surface roughness with a depth of 2mm or more was recorded as D, and the evaluation was stopped during the period. The evaluation results are shown in Table 3.

In addition, the so-called surface roughness depth refers to the surface roughness depth from the end of the ingot toward the center.

(Compound Observation)

The rolled surface of each sample was subjected to mirror polishing and ion etching. In order to confirm the compound containing Mg and P, an FE-SEM (field emission scanning electron microscope) was used to observe with a field of view of 10,000 times (approximately 120 μm ² /field).

Next, in order to investigate the density of the compound containing Mg and P (units/μm ² ), a 10,000-fold field of view (approximately 120 μm ² /field of view) was selected, and 10 fields of view (approximately 4.8 μm ² / Field of view) shooting. Regarding the particle size of the intermetallic compound, it is set as the long axis (the length of the longest straight line drawn from the grain under the condition that the period is not tangent to the grain boundary) and the short axis (at the intersection with the long axis at right angles) of the intermetallic compound. Direction, the average value of the length of the longest straight line drawn during the period when the grain boundary is not tangent Next, the density (pieces/μm ² ) of the compound containing Mg and P with a particle size of 0.1 μm or more and the compound containing Mg and P with a particle size of 0.05 μm or more was determined. An example of the observation results of the compound is shown in Figure 2A and Figure 2B.

(Mechanical characteristics)

For self-characteristic evaluation strips, a test piece No. 13B specified by JIS Z 2241 was taken, and 0.2% endurance was measured by the offset method of JIS Z 2241. In addition, the test piece was taken in a direction orthogonal to the rolling direction. The evaluation results are shown in Table 3.

(Conductivity)

A test piece with a width of 10 mm × a length of 150 mm was taken from the strip for characteristic evaluation, and the resistance was determined by the 4-terminal method. And use micrometers to measure the size of the test piece, and calculate the volume of the test piece. Next, the conductivity is calculated from the measured resistance value and volume. In addition, the test piece was taken so that its length direction was perpendicular to the rolling direction of the specific evaluation strip. The evaluation results are shown in Table 3.

(Resistance to stress relaxation characteristics)

The stress relaxation characteristic test is to measure the residual stress rate after being kept at a temperature of 150℃ for 1000 hours by the method of load stress in accordance with the technical standard JCBA-T309:2004 of the Japan Copper Elongation Association. The evaluation results are shown in Table 3.

As a test method, a test piece (width 10mm) is taken from the strip for property evaluation in a direction orthogonal to the rolling direction, and the initial flexural displacement is set to be such that the maximum surface stress of the test piece becomes 80% of the endurance 2mm, adjust the span length. The following formula determines the maximum stress on the surface.

Maximum surface stress (MPa)=1.5Etδ ₀ /L _s ²

but,

E: Young's modulus (MPa)

t: sample thickness (t=0.5mm)

δ ₀ : Initial deflection displacement (2mm)

L _s ：Span length (mm)

After maintaining the bending tendency at a temperature of 150°C for 1000 hours, the residual stress ratio was measured to evaluate the stress relaxation resistance. The residual stress rate was calculated using the following formula.

Residual stress rate (%)=(1-δ _t /δ ₀ )×100

but,

δ _t ：Permanent flexural displacement after keeping at 150℃ for 1000 hours (mm)-Permanent flexural displacement after keeping at room temperature for 24 hours (mm)

δ ₀ : Initial deflection displacement (mm)

(Bending workability)

Bending is carried out according to the 4 test method of the Japanese Copper Drawing Association technical standard JCBA-T307: 2007. With the bending axis being orthogonal to the rolling direction, a plurality of test pieces of 10mm wide×30mm long are used for the self-characteristic evaluation sheet, the bending angle is 90 degrees, and the bending radius is when the finishing rolling rate exceeds 85% 0.5mm (R/t=1.0), W-shaped fixture with a bending radius of 0.3mm (R/t=0.6) when the finishing rolling rate is less than 85%, perform W bending test

When a crack is observed on the outer periphery of the curved part by visual observation, it is recorded as "C", when a large wrinkle is observed, it is recorded as B, and when no fracture or fine cracks or large wrinkles are seen, it is recorded as A for judgment. In addition, A and B are judged to be allowable bending workability. The evaluation results are shown in Table 3.

In Comparative Example 1, the Mg content is less than the range of the present invention (0.15 mass% or more and less than 0.35 mass%), and the endurance and stress relaxation properties are insufficient.

In Comparative Example 2, the Mg content is more than the range of the present invention (0.15 mass% or more and less than 0.35 mass%), and the conductivity is low.

In Comparative Example 3, the P content was more than the range of the present invention (0.0005 mass% or more and less than 0.01 mass%), cracks occurred during the intermediate rolling and could not be evaluated.

In Comparative Examples 4 and 5, the Mg and P contents were large, and the cooling rate during casting was slow, so there were many compounds and poor bending workability.

In contrast, in the examples of the present invention, it was confirmed that the castability, strength (0.2% endurance), electrical conductivity, stress relaxation resistance (residual stress ratio), and bending workability were excellent. Based on the above, it is confirmed that according to the example of the present invention, it is possible to provide electronics with excellent conductivity and bending workability. Copper alloys for electrical equipment, electronics. Copper alloy plates and strips for electrical machines.

〔Industrial availability〕

The present invention provides electronics with excellent electrical conductivity and bending workability even when used in components that are thinned with miniaturization. Copper alloys for electrical equipment, electronics. Copper alloy sheet and strip for electrical equipment, electronics. Parts for electrical equipment, terminals, bus bars, and movable pieces for relays.

Claims (15)

A copper alloy for electronic and electrical equipment, which is characterized by containing Mg in the range of 0.15 mass% or more and less than 0.35 mass%, and P in the range of 0.0005 mass% or more and less than 0.01 mass%, and the remaining part is made of Cu and Impurities are unavoidable, and the conductivity exceeds 75% IACS, and in scanning electron microscope observation, the average number of compounds containing Mg and P with a particle size of 0.1μm or more is 0.5/μm ² or less. For example, the copper alloy for electrical and electronic equipment in claim 1, where the content of Mg [Mg] (mass%) and the content of P [P] (mass%) satisfy the following relationship: [Mg]+20×[P] <0.5. For example, the copper alloy for electrical and electronic equipment in claim 1 or 2, where the content of Mg [Mg] (mass%) and the content of P [P] (mass%) satisfy the following relationship: [Mg]/[P] ≦400. Such as claim 1 or 2 of the copper alloy for electrical and electronic equipment, wherein the 0.2% endurance is 300 MPa or more when the tensile test is carried out in the direction orthogonal to the rolling direction. Such as claim 1 or 2 of the copper alloy for electrical and electronic equipment, in which the residual stress rate is 50% or more at 150°C for 1000 hours. A copper alloy plate and strip for electrical and electronic equipment, characterized by being made of the copper alloy for electrical and electronic equipment as claimed in any one of claims 1 to 5. For example, the copper alloy plate and strip for electronic and electrical equipment in claim 6, which The surface has a Sn plating layer or Ag plating layer. A part for electrical and electronic equipment, characterized by being made of copper alloy plates and strips for electrical and electronic equipment as in Claim 6 or 7. For example, the electronic and electrical equipment parts of claim 8 have Sn plating layer or Ag plating layer on the surface. A terminal characterized by being made of copper alloy strips for electrical and electronic equipment as in Claim 6 or 7. For example, the terminal of claim 10 has a Sn plating layer or Ag plating layer on its surface. A bus bar characterized by being made of copper alloy plates and strips for electrical and electronic equipment as in Claim 6 or 7. For example, the bus bar of claim 12 has a Sn plating layer or Ag plating layer on its surface. A movable piece for relay, which is characterized by being made of copper alloy plates and strips for electrical and electronic equipment as in claim 6 or 7. For example, the movable piece for relay of claim 14 has a Sn plating layer or Ag plating layer on its surface.

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