JP6311299B2 - Copper alloy for electronic / electric equipment, copper alloy plastic working material for electronic / electric equipment, manufacturing method of copper alloy plastic working material for electronic / electric equipment, electronic / electric equipment parts and terminals - Google Patents

Description

The present invention relates to a copper alloy for electronic / electric equipment used as a terminal for a connector of a semiconductor device, a movable conductive piece of an electromagnetic relay, or a component for electronic / electric equipment such as a lead frame, and an electronic / electronic device using the same. The present invention relates to a copper alloy plastic working material for electric equipment, a method for producing a copper alloy plastic working material for electronic / electric equipment, parts for electronic / electric equipment, and terminals.

  Conventionally, along with downsizing of electronic equipment and electrical equipment, etc., miniaturization and thinning of electronic and electrical equipment parts such as connectors, relays, lead frames and other terminals used in such electronic equipment and electrical equipment are being attempted. It has been. For this reason, a copper alloy excellent in springiness, strength, and bending workability is required as a material constituting electronic / electric equipment parts. In particular, as described in Non-Patent Document 1, a copper alloy having high proof strength is desirable as a copper alloy used as a component for electronic and electrical equipment such as a terminal such as a connector, a relay, and a lead frame.

Here, as a copper alloy used for electronic and electrical equipment parts such as terminals such as connectors, relays, and lead frames, Cu-Mg alloys described in Non-Patent Document 2 and Patent Document 1 are described. Cu-Mg-Zn-B alloys and the like have been developed.
In these Cu-Mg based alloys, as can be seen from the Cu-Mg based phase diagram shown in Fig. 1, when the Mg content is 3.3 atomic% or more, by performing solution treatment and precipitation treatment, An intermetallic compound composed of Cu and Mg can be deposited. That is, these Cu—Mg alloys can have relatively high electrical conductivity and strength by precipitation hardening.

However, in the Cu—Mg-based alloys described in Non-Patent Document 2 and Patent Document 1, a large amount of coarse intermetallic compounds containing Cu and Mg are dispersed in the parent phase. Since these intermetallic compounds sometimes start from cracks and the like, there is a problem in that it is impossible to mold parts for electronic / electric equipment having complicated shapes.
In particular, electronic and electrical equipment parts used in consumer products such as mobile phones and personal computers are required to be smaller and lighter. Copper alloys for electronic and electrical equipment that have both strength and bending workability. Is required. However, in a precipitation hardening type alloy such as the above-described Cu-Mg alloy, bending workability is significantly reduced when the strength and proof stress are improved by precipitation hardening. For this reason, it was not possible to mold a thin and complicated part for electronic / electric equipment.

Therefore, Patent Document 2 proposes a work-hardening type copper alloy of a Cu—Mg supersaturated solid solution prepared by quenching a Cu—Mg alloy after solution.
This Cu-Mg alloy is excellent in balance of excellent strength, electrical conductivity, and bendability, and is particularly suitable as a material for the above-mentioned parts for electronic and electrical equipment.

Japanese Patent Laid-Open No. 07-018354 Japanese Patent No. 5045783

Yukiya Nomura, “Technology Trends of High Performance Copper Alloy Sheets for Connectors and Our Development Strategy”, Kobe Steel Technical Report Vol. 54No. 1 (2004) p. 2-8 M. Motokori and two others, “Grain boundary reaction type precipitation in Cu—Mg alloy”, Vol. 19 (1980) p. 115-124

By the way, parts for electronic and electrical equipment such as connectors are generally formed into a predetermined shape by punching a thin plate (rolled plate) having a thickness of about 0.05 to 1.0 mm, and bent to at least a part thereof. Manufactured by processing.
Recently, as electronic and electrical equipment is further reduced in size and weight, electronic parts for electronic and electrical equipment that have been reduced in size and weight have been manufactured by press molding (punching). ) High accuracy in time is an important issue. Further, in operation, there is a problem of a decrease in productivity due to wear of a press die and generation of punching scraps. From these viewpoints, there is a strong demand for the development of copper alloys for electronic and electrical equipment, which are superior in shear workability, compared to the prior art.

The present invention has been made in view of the above-described circumstances, and is a copper alloy for electronic / electric equipment that is excellent in strength and shear workability, a copper alloy plastic working material for electronic / electric equipment, and a copper for electronic / electric equipment. An object of the present invention is to provide a method for producing an alloy plastic processed material, a component for electronic / electric equipment, and a terminal.

In order to solve this problem, the copper alloy for electronic and electrical equipment of the present invention contains Mg in the range of 1.3 mass% to 2.8 mass%, and further contains Ca, Sr, Y, Te and rare earth elements. One or more of them is included in the range of 0.001 mass% or more and 0.020 mass% or less in total, the S content is in the range of 0.1 massppm or more and 50.0 massppm or less, and the balance is Cu. When the conductivity σ (% IACS) is Mg content X atom%,
σ ≦ 1.7241 / (− 0.0347 × X ² + 0.6569 × X + 1.7) × 100, and one or two of Ca, Sr, Y, Te and rare earth elements It is characterized by the presence of the above crystallized products .

According to the copper alloy for electronic / electric equipment having the above-described configuration, a total of at least one or two or more selected from Ca, Sr, Y, Te and rare earth elements is 0.001 mass% or more and 0.020 mass%. Since these elements are contained within the following ranges, many of these elements exist as crystallized substances, and these crystallized substances become the starting point of fracture during punching, and the shear workability is greatly improved. In addition, elements such as Ca, Sr, Y, Te, and rare earth elements react with O and S, which are inevitable impurities, to generate oxides and sulfides. Therefore, these oxides and sulfides are also destroyed during stamping. This contributes to the improvement of shear workability.
Further, as shown in the phase diagram of FIG. 1, Mg is contained in a range of 1.3 mass% to 2.8 mass% (3.3 atomic% to 6.9 atomic%) above the solid solution limit. In addition, since the electrical conductivity is within the above range, a Cu—Mg supersaturated solid solution in which Mg is supersaturated in the parent phase is obtained.

Further, since the content of S is in a range of less 50.0massppm above 0.1Massppm, S present in the copper reacts Mg, Ca, Sr, Y, and Te, and rare earth elements, the intermetallic Crystallized substances and precipitates are formed as compounds or sulfides. These crystallized substances and precipitates become the starting point of fracture during punching, and the shear workability can be greatly improved.

In a copper alloy composed of such a Cu-Mg supersaturated solid solution, a large amount of coarse intermetallic compounds mainly composed of Cu and Mg, which are the starting points of cracks, are not dispersed in the matrix phase, and bending workability is increased. Therefore, it becomes possible to mold terminals for complicated shapes such as connectors, and parts for electronic and electric devices such as relays and lead frames.
Further, since Mg is supersaturated, the strength can be improved by work hardening.
Note that the atomic% of Mg was calculated on the assumption that it was composed only of Cu, Mg, Ca, Sr, Y, Te, and rare earth elements. Further, since elements such as Ca, Sr, Y, Te, and rare earth elements hardly dissolve in copper, the calculation was performed by removing these elements in the calculation of the conductivity σ.

Furthermore, in the copper alloy for electronic / electric equipment of the present invention, the average number of intermetallic compounds mainly composed of Cu and Mg having a particle size of 0.1 μm or more is 1 / μm ² or less in the scanning electron microscope observation. It is preferable that
In this case, as shown in the phase diagram of FIG. 1, Mg is contained in a range of 1.3 mass% or more and 2.8 mass% or less (3.3 atomic% or more and 6.9 atomic% or less) above the solid solution limit. In addition, in the observation with a scanning electron microscope, since the average number of intermetallic compounds mainly composed of Cu and Mg having a particle size of 0.1 μm or more is 1 piece / μm ² or less, Cu and Mg Precipitation of an intermetallic compound containing as a main component is suppressed, and a Cu—Mg supersaturated solid solution in which Mg is supersaturated in the matrix is obtained. Therefore, as described above, a large amount of coarse intermetallic compounds mainly composed of Cu and Mg, which are the starting points of cracking, are not dispersed in the matrix phase, and the bending workability can be improved. Further, since Mg is supersaturated, the strength can be improved by work hardening.

The average number of intermetallic compounds mainly composed of Cu and Mg having a particle size of 0.1 μm or more was 10 × 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. Calculate by observing the visual field.
In addition, the particle size of the intermetallic compound containing Cu and Mg as the main components is the major axis of the intermetallic compound (the length of the straight line that can be drawn the longest in the grain under the condition of not contacting the grain boundary in the middle) and the minor axis (major axis and It is defined as an average value of the length of a straight line that can be drawn longest in a direction that intersects at right angles and does not contact the grain boundary in the middle.

In the copper alloy for an electrical and electronic equipment of the present invention, further, 0.02 mass% or less of Sn, 0.1mass% less Zn, 0.2 mass% or less of Al, 0.1mass% less Ni, 0 0.05 mass% or less Si, 0.1 mass% or less Mn, 0.2 mass% or less Li, 0.04 mass% or less Ti, 0.05 mass% or less Fe, 0.05 mass% or less Co, 0.03 mass % or less of Cr, 0.02 mass% or less of Zr, 1 or two or more may be free Ndei of 0.05 mass% or less of P.
Since these elements have the effect of improving the properties such as the strength of the Cu—Mg alloy, it is preferable to add them appropriately according to the required properties .

Furthermore, the copper alloy for electronic / electric equipment of the present invention preferably has a mechanical property of 0.2% proof stress of 400 MPa or more.
In this case, since the 0.2% proof stress is 400 MPa or more, the plasticity is not easily deformed and the spring property can be ensured. Therefore, particularly for electronic device parts such as terminals such as connectors, relays, and lead frames. Is suitable.

Electronic and electrical equipment copper alloy plastic working material of the present invention is characterized and Turkey such from electrical and electronic equipment for copper alloy described above. In this specification, the plastic working material refers to a copper alloy that has undergone plastic working in any manufacturing process.
In the copper alloy plastic work material of this configuration, as described above, it is made of a copper alloy for electronic / electric equipment having excellent strength, bending workability, and shear workability. Is suitable.
Moreover, in the copper alloy plastic working material for electronic / electric equipment of this invention, Sn plating may be given to the surface.
In this case, when the terminal / connector is molded, the contact resistance between the contacts is stabilized, and the corrosion resistance can be improved.

The method for producing a copper alloy plastic working material for electronic / electric equipment according to the present invention includes a heating step of heating a copper material made of the above-described copper alloy for electronic / electric equipment to a temperature of 400 ° C. or higher and 900 ° C. or lower, and heating. and rapid cooling step of cooling to the copper material to 200 ° C. or less at 60 ° C. / min or more cooling speed, is characterized in Rukoto to have a, a plastic working step of plastic working the copper material.
In this case, the solution of Mg can be formed by heating the copper material having the above composition to a temperature of 400 ° C. or higher and 900 ° C. or lower. Moreover, it can suppress that an intermetallic compound precipitates in the process of cooling by cooling the said copper raw material heated to 200 degrees C or less with the cooling rate of 60 degrees C / min or more, and makes a copper raw material Cu-Mg. A supersaturated solid solution can be obtained. Therefore, a large amount of coarse intermetallic compounds mainly composed of Cu and Mg are not dispersed in the parent phase, and the bending workability is improved.

The component for electronic / electrical equipment of the present invention is characterized by comprising the above-described copper alloy plastic working material for electronic / electrical equipment. In addition, the electronic / electric equipment parts in the present invention include terminals such as connectors, relays, lead frames, and the like.
The terminal of the present invention is characterized by comprising the above-described copper alloy plastic working material for electronic / electrical equipment.
Since the components and terminals for electronic / electrical equipment of this configuration are manufactured using a copper alloy plastic working material for electronic / electrical equipment with excellent mechanical properties, there are no cracks even in complex shapes, Since the strength is sufficiently secured, it is excellent in reliability.

According to the present invention, a copper alloy for electronic / electric equipment having excellent strength and shear workability, a copper alloy plastic working material for electronic / electric equipment, a method for producing a copper alloy plastic working material for electronic / electric equipment, electronic / electrical Equipment parts and terminals can be provided.

It is a Cu-Mg system phase diagram. It is a flowchart of the manufacturing method of the copper alloy for electronic and electric apparatuses which is this embodiment. It is explanatory drawing of the torn surface ratio which evaluates the shear workability in an Example.

Embodiments of the present invention will be described below with reference to the drawings.
The component composition of the copper alloy for electronic / electric equipment according to the present embodiment includes Mg in a range of 1.3 mass% to 2.8 mass% (3.3 atomic% to 6.9 atomic%), One or more of Ca, Sr, Y, Te and rare earth elements are included within a total range of 0.001 mass% or more and 0.020 mass% or less, with the balance being substantially Cu and inevitable impurities. Yes. In the present embodiment, the S content is in the range of 0.1 massppm to 50.0 massppm.
Furthermore, in the copper alloy for electronic / electric equipment according to the present embodiment, the 0.2% proof stress is set to 400 MPa or more.

Here, when the conductivity σ (% IACS) is set to the Mg content X atom%,
It is within the range of σ ≦ 1.7241 / (− 0.0347 × X ² + 0.6569 × X + 1.7) × 100.
In the observation with a scanning electron microscope, the average number of intermetallic compounds mainly composed of Cu and Mg having a particle diameter of 0.1 μm or more is set to 1 piece / μm ² or less.
That is, the copper alloy for electronic and electrical equipment according to the present embodiment has almost no intermetallic compound mainly composed of Cu and Mg, and Mg is a solid solution exceeding the solid solution limit in the matrix phase. -Mg supersaturated solid solution.

  Here, the reason why the component composition, the conductivity, and the number of precipitates are defined as described above will be described below.

(Mg: 1.3 mass% or more and 2.8 mass% or less)
Mg is an element that has the effect of improving the strength and raising the recrystallization temperature without greatly reducing the electrical conductivity. Further, excellent bending workability can be obtained by dissolving Mg in the matrix.
Here, when the content of Mg is less than 1.3 mass%, the effect cannot be achieved. On the other hand, when the Mg content exceeds 2.8 mass%, when heat treatment is performed for solution treatment, an intermetallic compound mainly containing Cu and Mg remains, and subsequent hot working and There is a risk of cracking during cold working. For these reasons, the Mg content is set to 1.3 mass% or more and 2.8 mass% or less (3.3 atomic% or more and 6.9 atomic% or less).

  In addition, when there is little content of Mg, intensity | strength will not fully improve. Moreover, since Mg is an active element, when it is added excessively, there is a possibility that Mg oxide generated by reacting with oxygen is involved during melt casting. Therefore, it is more preferable that the Mg content is in the range of 1.4 mass% to 2.6 mass% (3.7 atomic% to 6.3 atomic%).

(Ca, Sr, Y, Te and rare earth elements: 0.001 mass% or more and 0.020 mass% or less in total)
Many elements such as Ca, Sr, Y, Te, and rare earth elements are present as crystallized substances in copper, and since these crystallized substances become the starting point of fracture during stamping, the shear workability is greatly improved. To do. In addition, elements such as Ca, Sr, Y, Te, and rare earth elements react with O and S, which are inevitable impurities, to generate oxides and sulfides. Therefore, these oxides and sulfides are also destroyed during stamping. This contributes to the improvement of shear workability. Moreover, O and S can be rendered harmless and adverse effects on characteristics can be suppressed.
Here, when the content of one or more of Ca, Sr, Y, Te, and rare earth elements is less than 0.001 mass% in total, a desired effect cannot be obtained. On the other hand, when the content of one or more of Ca, Sr, Y, Te, and rare earth elements exceeds 0.020 mass% in total, in addition to a decrease in conductivity, a crystallization product or a precipitate Therefore, the hot workability and the cold workability may be deteriorated.
Therefore, the total of the content of one or more of Ca, Sr, Y, Te and rare earth elements is set in the range of 0.001 mass% to 0.020 mass%. The total content of one or more of Ca, Sr, Y, Te and rare earth elements is preferably within the range of 0.002 mass% to 0.015 mass%, even within the above range.

(S: 0.1 massppm or more and 50.0 massppm or less)
S exists in copper in the form of a simple substance, an intermetallic compound, a composite sulfide or the like. S present in copper reacts with Mg, Ca, Sr, Y, Te and rare earth elements to form crystallized substances and precipitates as intermetallic compounds or sulfides. Since these intermetallic compounds or sulfides serve as starting points for fracture during shearing, the shear workability is greatly improved. Here, when the content of S is less than 0.1 mass ppm, the amount of intermetallic compounds or sulfides to be generated is decreased, and there is a possibility that further improvement in shear workability is not recognized. On the other hand, when the content of S exceeds 50.0 massppm, the cold workability may be deteriorated.
Therefore, in the present embodiment, the content of S is set to 0.1 massppm or more and 50.0 massppm or less. In addition, the content of S is preferably 1.0 mass ppm or more and 40.0 mass ppm or less, and more preferably 2.0 mass ppm or more and 40.0 mass ppm or less even within the above range.

  The balance of the above elements may be basically Cu and inevitable impurities. Here, as inevitable impurities, Ag, B, Ba, Sc, Hf, V, Nb, Ta, Mo, W, Re, Ru, Os, Se, Rh, Ir, Pd, Pt, Au, Cd, Ga , In, Ge, As, Sb, Tl, Pb, Bi, Be, N, Hg, H, C, O, S, Sn, Zn, Al, Ni, Si, Mn, Li, Ti, Fe, Co, Cr , Zr, P and the like. These inevitable impurities are desirably 0.3 mass% or less in total.

(Conductivity σ)
In the copper alloy for electronic and electrical equipment according to the present embodiment having the above-described component composition, when the conductivity σ is Mg content X atom%, σ ≦ 1.7241 / (− 0.0347 In the case of × X ² + 0.6569 × X + 1.7) × 100, there is almost no intermetallic compound.
That is, when the electrical conductivity σ exceeds the above formula, a large amount of intermetallic compounds are present and the size is relatively large, so that the bending workability is greatly deteriorated. Therefore, the manufacturing conditions are adjusted so that the electrical conductivity σ is within the range of the above formula.
In order to ensure that the above-described effects are achieved, the conductivity σ (% IACS) is
It is preferable that σ ≦ 1.7241 / (− 0.0292 × X ² + 0.6797 × X + 1.7) × 100. In this case, since the amount of the intermetallic compound mainly composed of Cu and Mg is smaller, the bending workability is further improved.

(Precipitate)
In the copper alloy for electronic and electrical equipment according to this embodiment, as a result of observation with a scanning electron microscope, the average number of intermetallic compounds mainly composed of Cu and Mg having a particle size of 0.1 μm or more is 1 / It is set to μm ² or less. That is, almost no intermetallic compound mainly composed of Cu and Mg is precipitated, and Mg is dissolved in the matrix.
Here, when the solution formation is incomplete, or when an intermetallic compound mainly composed of Cu and Mg is precipitated after solution formation, a large amount of intermetallic compounds exist in a large size. It becomes a starting point of cracking, and bending workability is greatly deteriorated.

As a result of investigating the structure, when the intermetallic compound containing Cu and Mg as main components having a particle size of 0.1 μm or more is 1 / μm ² or less in the alloy, that is, the intermetallic compound containing Cu and Mg as main components. When there is no or a small amount, good bending workability can be obtained.
Furthermore, in order to ensure that the above-described effects are achieved, the number of intermetallic compounds mainly composed of Cu and Mg having a particle diameter of 0.05 μm or more is 1 / μm ² or less in the alloy. More preferred.

The average number of intermetallic compounds mainly composed of Cu and Mg was observed using a field emission scanning electron microscope with 10 fields of view at a magnification of 50,000 times and a field of view of about 4.8 μm ^2. The average value is calculated.
In addition, the particle size of the intermetallic compound containing Cu and Mg as the main components is the major axis of the intermetallic compound (the length of the straight line that can be drawn the longest in the grain under the condition of not contacting the grain boundary in the middle) and the minor axis (major axis and It is defined as an average value of the length of a straight line that can be drawn longest in a direction that intersects at right angles and does not contact the grain boundary in the middle.
Here, the intermetallic compound containing Cu and Mg as main components has a crystal structure represented by the chemical formula MgCu ₂ , prototype MgCu ₂ , Pearson symbol cF24, and space group number Fd-3m.

  Next, referring to the flowchart shown in FIG. 2 for the manufacturing method of the copper alloy for electronic and electrical equipment and the manufacturing method of the copper alloy plastic working material for electronic and electrical equipment according to the present embodiment configured as described above. I will explain.

(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, Mg simple substance, Cu-Mg master alloy, etc. can be used for addition of Mg. Moreover, you may melt | dissolve the raw material containing Mg with a copper raw material. Further, recycled materials and scrap materials of this alloy may be used. Moreover, an element simple substance, a mother alloy, etc. can also be used for addition of at least one element selected from Ca, Sr, Y, Te and rare earth elements.
Here, the molten copper is preferably so-called 4NCu having a purity of 99.99 mass% or more. Further, in the melting step, it is preferable to use a vacuum furnace or an atmosphere furnace having an inert gas atmosphere or a reducing atmosphere in order to suppress oxidation of Mg.

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.
Here, the cooling rate during solidification in casting is 30 ° C./sec. In order to sufficiently crystallize the particles formed of the above-mentioned Ca, Sr, Y, Te and rare earth elements. It is preferable to be less than 0.1 ° C./sec. 25 ° C./sec. It is preferable to make it less than.

(Heating step S02)
Next, heat treatment is performed for homogenization and solution of the obtained ingot. Inside the ingot, there are intermetallic compounds and the like mainly composed of Cu and Mg generated by the concentration of Mg by segregation during the solidification process. Therefore, in order to eliminate or reduce these segregation and intermetallic compounds, etc., heat treatment is performed to heat the ingot to 400 ° C. or more and 900 ° C. or less, so that Mg can be uniformly diffused in the ingot. Mg is dissolved in the matrix. The heating step S02 is preferably performed in a non-oxidizing or reducing atmosphere.
Here, when the heating temperature is less than 400 ° 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 400 ° C. or higher and 900 ° C. or lower. More preferably, it is 400 degreeC or more and 850 degrees C or less, More preferably, you may be 420 degreeC or more and 800 degrees C or less.

(Rapid cooling step S03)
And the copper raw material heated to 400 degreeC or more and 900 degrees C or less in heating process S02 is cooled by the cooling rate of 60 degrees C / min or more to the temperature of 200 degrees C or less. This rapid cooling step S03 suppresses the precipitation of Mg dissolved in the matrix as an intermetallic compound containing Cu and Mg as main components. In observation with a scanning electron microscope, Cu having a particle diameter of 0.1 μm or more is suppressed. The average number of intermetallic compounds containing Mg and Mg as main components can be 1 / μm ² or less. That is, the copper material can be a Cu—Mg supersaturated solid solution.
In addition, in order to increase the efficiency of roughing and make the structure uniform, it is possible to perform a hot working after the heating step S02 and perform the rapid cooling step S03 after the hot working. In this case, the processing method is not particularly limited, and for example, rolling, wire drawing, extrusion, groove rolling, forging, pressing, and the like can be employed. The hot working temperature is preferably in the range of 400 ° C. or higher and 900 ° C. or lower.

(Intermediate processing step S04)
The copper material that has undergone the heating step S02 and the rapid cooling step S03 is cut as necessary, and surface grinding is performed as necessary to remove the oxide film and the like generated in the heating step S02, the rapid cooling step S03, and the like. Then, plastic working is performed into a predetermined shape.
In addition, the temperature condition in the intermediate processing step S04 is not particularly limited, but it is preferable to be within a range of −200 ° C. to 200 ° C. which is cold or warm processing. The processing rate is appropriately selected so as to approximate the final shape, but is preferably 50% or more, and more preferably 60% or more. The plastic working method is not particularly limited, and for example, rolling, wire drawing, extrusion, groove rolling, forging, pressing, and the like can be employed. Further, S02 to S04 may be repeated for thorough solution.

(Intermediate heat treatment step S05)
After the intermediate processing step S04, heat treatment is performed for the purpose of thorough solution, recrystallization structure, or softening for improving workability.
The heat treatment method is not particularly limited, but the heat treatment is preferably performed in a non-oxidizing atmosphere or a reducing atmosphere under conditions of 400 ° C. to 900 ° C. More preferably, it is 400 degreeC or more and 850 degrees C or less, More preferably, you may be 420 degreeC or more and 800 degrees C or less.
Here, in the intermediate heat treatment step S05, it is preferable to cool the copper material heated to 400 ° C. or higher and 900 ° C. or lower to a temperature of 200 ° C. or lower at a cooling rate of 60 ° C./min or higher.

(Finishing process S06)
The copper material after the intermediate heat treatment step S05 is finished into a predetermined shape. The temperature condition in the finishing step S06 is not particularly limited, but is preferably set to −200 to 200 ° C. which is cold or warm so that the solutionized Mg does not precipitate. The processing rate is appropriately selected so as to approximate the final shape, but is preferably 20% or more, and more preferably 30% or more.

(Finish heat treatment step S07)
Next, a finish heat treatment for removing strain is performed on the copper material after the finish processing step S06. The heat treatment temperature is preferably in the range of 200 ° C to 800 ° C. In the finish heat treatment step S07, it is necessary to set heat treatment conditions (temperature, time, cooling rate) so that solutionized Mg does not precipitate. For example, it is preferably about 1 minute to 24 hours at 200 ° C. and about 1 second to 10 seconds at 400 ° C. This heat treatment is preferably performed in a non-oxidizing atmosphere or a reducing atmosphere.

Moreover, it is preferable that a cooling method cools the said copper raw material heated, such as water quenching, to 100 degrees C or less with the cooling rate of 60 degrees C / min or more. By quenching in this way, Mg dissolved in the matrix phase is prevented from precipitating as an intermetallic compound mainly composed of Cu and Mg, and the copper material is made a Cu-Mg supersaturated solid solution. be able to.
Furthermore, the above-described finishing processing step S06 and finishing heat treatment step S07 may be repeated.

Thus, the copper alloy for electronic / electric equipment and the copper alloy plastic working material for electronic / electric equipment according to the present embodiment are produced. In addition, in this copper alloy plastic working material for electronic / electric equipment, Sn plating with a film thickness of about 0.1 μm or more and 10 μm or less may be applied to the surface.
The method of Sn plating in this case is not particularly limited, but electrolytic plating may be applied according to a conventional method, or depending on the case, reflow treatment may be performed after electrolytic plating.
In addition, the electronic / electric device parts and terminals according to the present embodiment are manufactured by punching, bending, or the like to the above-described copper alloy plastic working material for electronic / electric devices.

  According to the copper alloy for electronic / electric equipment according to the present embodiment configured as described above, at least one selected from Ca, Sr, Y, Te, and rare earth elements, or two or more selected in total. Since it is contained within the range of 0.001 mass% or more and 0.020 mass% or less, there are many crystallized substances, oxides and sulfides composed of these elements, and these particles are destroyed during the punching process. As a starting point, the shear processability is greatly improved. Therefore, it is possible to cope with high accuracy at the time of press molding (punching), and it is possible to suppress wear of the press die and generation of punching waste.

  Further, in the present embodiment, since S is contained in an amount of 0.1 mass ppm or more, S present in copper reacts with Mg, Ca, Sr, Y, Te and rare earth elements to form crystals as intermetallic compounds or sulfides. A deposit and a precipitate are formed, and the shear workability can be further improved. Moreover, since content of S shall be 50.0 massppm or less, cold workability is ensured and the copper alloy plastic working material for electronic / electric equipment can be manufactured favorably.

Further, in the copper alloy for electronic / electric equipment of the present embodiment, the average number of intermetallic compounds mainly composed of Cu and Mg having a particle diameter of 0.1 μm or more is 1 / μm in the observation with a scanning electron microscope. ² or less, and the electrical conductivity σ (% IACS) is set when the Mg content is X atom%,
σ ≦ 1.7241 / (− 0.0347 × X ² + 0.6569 × X + 1.7) × 100, and a Cu—Mg supersaturated solid solution in which Mg is supersaturated in the matrix phase. ing.

  For this reason, a large amount of coarse intermetallic compounds mainly composed of Cu and Mg, which are the starting points of cracks, are not dispersed in the matrix, and the bending workability is improved. Accordingly, it is possible to mold terminals such as connectors having complicated shapes, and parts for electronic and electric devices such as relays and lead frames. Further, since Mg is supersaturated, the strength can be improved by work hardening.

  Here, in this embodiment, the heating step S02 for heating the copper material having the above composition to a temperature of 400 ° C. or more and 900 ° C. or less, and the heated copper material at a cooling rate of 60 ° C./min or more, Since it is manufactured by a manufacturing method having a rapid cooling step S04 for cooling to 200 ° C. or less, an intermediate processing step S04 for plastic processing of a copper material, and a finishing processing step S06, the copper alloy for electronic / electric equipment is described above. Thus, a Cu—Mg supersaturated solid solution in which Mg is supersaturated in the matrix phase can be obtained.

  Furthermore, in this embodiment, the cooling rate during solidification in casting is 30 ° C./sec. And preferably 0.1 ° C./sec. 25 ° C./sec. Since it is within the range of less than the above, particles such as crystallized substances formed by the above-mentioned Ca, Sr, Y, Te and rare earth elements can be sufficiently present, and the shear workability is surely improved. Can do.

In addition, in the copper alloy for electronic and electrical equipment according to the present embodiment, since 0.2% proof stress has mechanical characteristics of 400 MPa or more, it is not easily plastically deformed, and terminals such as connectors, relays, It can be suitably used as a material for electronic device parts such as lead frames.
Furthermore, since the components and terminals for electronic / electrical equipment according to the present embodiment are manufactured using the above-described copper alloy plastic working material for electronic / electrical equipment, the proof stress is high, and the bending workability and shearing are high. Even if it is a complicated shape, it can be molded with high accuracy and there is no crack or the like, and the reliability is improved.

As described above, the copper alloy for electronic / electric equipment, the copper alloy plastic working material for electronic / electric equipment, the parts for electronic / electric equipment and the terminal according to the embodiment of the present invention have been described, but the present invention is limited to this. However, it can be appropriately changed without departing from the technical idea of the invention.
For example, in the above-described embodiment, an example of a method for manufacturing a copper alloy for electronic / electric equipment and a method for manufacturing a copper alloy plastic working material for electronic / electric equipment has been described. However, the manufacturing method is limited to this embodiment. Instead, existing manufacturing methods may be selected as appropriate.

In the present embodiment, the description has been made assuming that Ca, Sr, Y, Te and rare earth elements are added to the Cu—Mg alloy, but the present invention is not limited to this, and Sn, Zn, Al, Ni, Si, One or more of Mn, Li, Ti, Fe, Co, Cr, Zr, and P may be included within a total range of 0.01 mass% or more and 2.00 mass% or less.
Elements such as Sn, Zn, Al, Ni, Si, Mn, Li, Ti, Fe, Co, Cr, Zr, and P are elements that improve characteristics such as strength of the Cu-Mg alloy. Accordingly, it is preferable to add appropriately. Here, since the total amount of addition is set to 0.01 mass% or more, the strength of the Cu-Mg alloy can be reliably improved. On the other hand, since the total amount of addition is 2.00 mass% or less, electrical conductivity can be ensured.
In addition, when containing the above-mentioned element, although regulation of the electrical conductivity demonstrated by embodiment is not applied, it can confirm that it is a supersaturated solid solution of Cu-Mg from the distribution state of a precipitate.

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 carbon mold to produce an ingot. Here, the size of the ingot was about 120 mm thick × about 220 mm wide × about 300 mm long. The cooling rate during casting was 0.1 ° C./sec. 20 ° C./sec. Within the range of less than.
Further, it was assumed that at% (atomic%) of the composition shown in Table 1 was composed only of Cu, Mg and other additive elements, and atomic% was calculated from the measured mass% value.

From the obtained ingot, the vicinity of the casting surface was chamfered by 10 mm or more, and a block of 100 mm × 200 mm × 100 mm was cut out.
This block was held for 4 hours under the temperature conditions shown in Table 2 in an Ar gas atmosphere, and then water quenching was performed.

Next, 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, as an intermediate processing step, cold rolling was performed at room temperature at a rolling rate described in Table 2.
Next, as an intermediate heat treatment, heat treatment was performed using a salt bath under the temperature conditions described in Table 2, and water quenching was performed.

Next, finish rolling was performed at the rolling rates shown in Table 2 to produce a thin plate having a thickness of 0.5 mm and a width of about 200 mm.
Then, after finish rolling, 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.

(Processability evaluation)
As an evaluation of workability, the presence or absence of ear cracks during the above-described intermediate rolling and finish rolling was observed. The case where no or almost no ear cracks were visually observed was ◎, the case where a small ear crack of less than 1 mm in length occurred was ○, the case where an ear crack of 1 mm or more and less than 3 mm occurred was Δ, and a length of 3 mm The case where the above-mentioned big ear crack generate | occur | produced was made into x, and what was fractured | ruptured in the middle of rolling due to the ear crack was made into xx.
In addition, the length of an ear crack is the length of the ear crack which goes to the width direction center part from the width direction edge part of a rolling material.

(Precipitate observation)
Mirror polishing and ion etching were performed on the rolled surface of each sample. In order to confirm the precipitation state of the intermetallic compound containing Cu and Mg as main components, the observation was performed using a FE-SEM (Field Emission Scanning Electron Microscope) with a 10,000 × field of view (about 120 μm ² / field of view). .
Next, in order to investigate the density of intermetallic compounds mainly composed of Cu and Mg (pieces / μm ² ), a 10,000 times field of view (about 120 μm ² / field of view) where the precipitation state of intermetallic compounds is not unique. In this region, 10 fields of view (about 4.8 μm ² / field of view) were taken at a magnification of 50,000 times. 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 intermetallic compound which has a particle size of 0.1 micrometer or more and which has Cu and Mg as a main component was calculated | required.

(Shear workability)
A number of square holes (8 mm x 8 mm) are punched from a thin plate for characteristic evaluation with a mold, and the fracture surface ratio (ratio of the fracture surface to the thickness of the punched portion) and burr height are measured as shown in FIG. Evaluation was performed. The punched cut surface has a fracture surface and a shear surface. The smaller the ratio of the shear surface and the greater the proportion of the fracture surface, the better the shear workability.
The die clearance was 0.02 mm, and punching was performed at a punching speed of 50 spm (stroke per minute). The measurement of the fracture surface ratio and the burr height was performed by observing the cut surface on the punching side and evaluating the average of 10 measurement points.
In addition, the thing whose burr height is 6 micrometers or less was evaluated as "(circle)", and the thing exceeding 6 micrometers was evaluated as "x".

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

(conductivity)
A test piece having a width of 10 mm and a length of 150 mm was collected from the thin plate 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 thin plate for characteristic evaluation.

  The component composition is shown in Table 1, the production conditions are shown in Table 2, and the evaluation results are shown in Table 3.

In Comparative Example 1 in which the Mg content was less than the range of the present invention, the yield strength was as low as 377 MPa. Further, the fracture surface ratio was 28%, the burr height evaluation was x, and the shear workability was extremely inferior.
In Comparative Example 2 in which the content of Mg is larger than the range of the present invention, large ear cracks occurred during cold rolling in the intermediate process, and it was impossible to perform subsequent characteristic evaluation.
Although the content of Mg is within the scope of the present invention, in Comparative Example 3 that does not contain elements such as Ca, Sr, Y, Te and rare earth elements, the fracture surface ratio is 35%, and the shear workability is high. It was insufficient.
Although the content of Mg is within the range of the present invention, the content of elements such as Ca, Sr, Y, Te, and rare earth elements is larger than the range of the present invention. Large ear cracks occurred and it was impossible to conduct subsequent characteristic evaluation.

In contrast, the Mg content is within the scope of the present invention, and one or more of Ca, Sr, Y, Te, and rare earth elements are added in a total amount of 0.001 mass% or more and 0.020 mass. In Invention Example 1-8 contained in the range of not more than%, the proof stress was high and the shear workability was excellent. Moreover, there was no occurrence of ear cracks.
Furthermore, Sn, Zn, Al, Ni, Si, Mn, Li, Ti, Fe, Co, Cr, Zr, and P may be one or more in total of 0.01 mass% or more and 2.00 mass% or less. Also in Invention Example 9-15 included in the above range, as in Invention Example 1-8, the proof stress was high and the shear workability was excellent. Moreover, there was no occurrence of ear cracks.

  From the above, according to the present invention, it was confirmed that a copper alloy for electronic / electric equipment and a copper alloy plastic working material for electronic / electric equipment excellent in strength and shear workability can be provided.

Claims (9)

Mg is included in the range of 1.3 mass% or more and 2.8 mass% or less, and one or more of Ca, Sr, Y, Te and rare earth elements are added in a total of 0.001 mass% to 0.020 mass%. In the following range, S content is in the range of 0.1 massppm or more and 50.0 massppm or less, the balance is Cu and inevitable impurities ,
When the electrical conductivity σ (% IACS) is Mg content X atom%,
σ ≦ 1.7241 / (− 0.0347 × X ² + 0.6569 × X + 1.7) × 100,
A copper alloy for electronic and electrical equipment, characterized by the presence of one or more crystallized substances of Ca, Sr, Y, Te, and rare earth elements . In scanning electron microscopy, the average number of intermetallic compounds mainly containing more particle size 0.1μm of Cu and Mg, according to claim 1, characterized in that it is a one / [mu] m ² or less Copper alloy for electronic and electrical equipment. Furthermore, 0.02 mass% or less of Sn, 0.1mass% less Zn, 0.2 mass% or less of Al, 0.1mass% less Ni, 0.05 mass% or less of Si, 0.1mass% Mn, up 0.2 mass% or less of Li, 0.04mas% less Ti, 0.05 mass% or less of Fe, 0.05 mass% or less of Co, 0.03 mass% or less of Cr, 0.02 mass% or less of Zr, 0. 05Mass% or less of one or more electric and electronic components for a copper alloy according to claim 2, characterized in that has Nde free of P. The copper alloy for electronic / electric equipment according to any one of claims 1 to 3, wherein a 0.2% proof stress is 400 MPa or more. Electronic and electrical equipment copper alloy plastic working material, wherein the benzalkonium such from electrical and electronic equipment for copper alloy according to any one of claims 1 to 4. 6. The copper alloy plastic working material for electronic / electric equipment according to claim 5 , wherein Sn plating is applied to the surface. A heating step of heating the copper material made of the copper alloy for electronic / electric equipment according to any one of claims 1 to 4 to a temperature of 400 ° C or higher and 900 ° C or lower, and the heated copper material and rapid cooling step of cooling down to 200 ° C. or less at 60 ° C. / min or more cooling rate, plastic working step and the copper for electronic and electrical equipment, characterized and Turkey which have a alloy plasticity plastic working the copper material Manufacturing method of processed material. An electronic / electric equipment part comprising the copper alloy plastic working material for electronic / electric equipment according to claim 5 . A terminal comprising the copper alloy plastic working material for an electronic / electrical device according to claim 5 or 6 .