JP2020128598A - Rolled copper sheet, and component for electronic and electric apparatus - Google Patents

Abstract

To provide a rolled copper sheet excellent in electric conductivity, and stress relaxation resistance characteristics, capable of suppressing generation of defects, and suitable for a component for an electronic and electric apparatus.SOLUTION: A rolled copper sheet includes 0.005 mass% or more and 0.05 mass% or less of Mg, and the balance of Cu and inevitable impurities, where the content of H is less than 1 mass ppm, the content of P is less than 10 mass ppm, the content of O is less than 5 mass ppm, the content of S is less than 10 mass ppm, the ratio (P+O+S)/Mg of a total amount (P+O+S) of P, O, and S to an amount of Mg is smaller than 0.6, the conductivity is larger than 95% IACS, the residual stress rate at 150°C for 1,000 hrs. is 20% or more, and the broken test piece number in an elastic region before reaching a yield point is less than 1 when performing 10 times of a tensile test using 13B test pieces specified in JIS Z 2241.SELECTED DRAWING: None

Description

The present invention relates to a rolled copper plate used for electric/electronic parts such as lead frames, terminals, connectors, etc., and particularly to a rolled copper plate excellent in conductivity and stress relaxation resistance and parts for electronic/electrical equipment. Is.

2. Description of the Related Art Conventionally, highly conductive copper or copper alloys have been used for electronic/electrical device parts such as terminals such as connectors, relays, and lead frames.
Here, stress relaxation resistance is required for terminals and the like of connectors and the like used in high temperature environments such as engine rooms of automobiles.

Here, for example, in a high-voltage harness used in an electric vehicle, a hybrid vehicle, or the like, oxygen-free copper or the like having excellent conductivity is applied in order to handle a large current. Since the harness made of oxygen-free copper has insufficient stress relaxation resistance, it cannot be made into a terminal, and conventionally, it is connected by bolting.

Here, Cu-Mg-P alloy described in Patent Document 1 and Patent Document 2 are described as materials used for parts for electronic/electrical devices such as terminals such as connectors, relays, and lead frames. Cu-Mg alloys have been developed.
Further, Patent Document 3 discloses a technique for improving the fatigue strength of a rolled copper alloy plate made of pure copper by defining a special grain boundary ratio.

JP, 2007-056297, A JP, 2014-114464, A JP2012-062498A

However, in the Cu-Mg-P alloy described in Patent Document 1, the Mg content is relatively large at 0.1 to 0.4% by mass, and thus the electrical conductivity was insufficient.
In the Cu-Mg alloy described in Patent Document 2, the content of Mg is specified to be 0.01 to 0.5% by mass, and when the content of Mg is large, ensure conductivity. I can't. Further, in Patent Document 2, since H (hydrogen) that causes a blowhole defect is not taken into consideration at all, there is a possibility that a defect is likely to occur during processing and the manufacturing yield may be significantly reduced.
In the copper rolled plate described in Patent Document 3, when oxygen-free copper is used, the conductivity can be secured, but the stress relaxation resistance is insufficient and it cannot be formed into a terminal. It was

The present invention has been made in view of the above-mentioned circumstances, and has excellent conductivity and stress relaxation resistance, and is a copper rolled plate suitable for electronic/electrical device parts capable of suppressing the occurrence of defects. It is also an object of the present invention to provide a component for electronic/electrical equipment made of this rolled copper plate.

In order to solve this problem, the rolled copper plate of the present invention contains Mg in the range of 0.005 mass% or more and 0.05 mass% or less, the balance is Cu and inevitable impurities, and the H content is less than 1 mass ppm, The content of P is less than 10 massppm, the content of O is less than 5 massppm, the content of S is less than 10 massppm, and the mass ratio (P+O+S)/Mg of the total amount of P, O and S (P+O+S) and the amount of Mg is 0. The tensile stress test is conducted by using a No. 13B test piece specified in JIS Z 2241, which has a conductivity of 95% IACS or more, a residual stress rate of 20% or more at 150° C. for 1000 hours, as well as being set to 0.6 or less. Is performed 10 times and before the yield point is reached, the number of ruptures in the tensile test, which is the number of tensile test pieces ruptured in the elastic region, is less than 1.

According to the copper rolled sheet having the above-described structure, Mg is contained in the range of 0.005 mass% or more and 0.05 mass% or less, and the balance has the composition of Cu and inevitable impurities. It is possible to form a solid solution in it, and it is possible to improve the strength and the stress relaxation resistance characteristic without significantly reducing the conductivity.
Further, since the H content is less than 1 massppm, it is possible to suppress the occurrence of blowhole defects in the ingot, and it is possible to suppress the occurrence of defects during processing.
Furthermore, the content of P is less than 10 massppm, the content of O is less than 5 massppm, the content of S is less than 10 massppm, and the mass ratio (P+O+S)/Mg of the total amount of P, O and S (P+O+S) and the amount of Mg (P+O+S)/Mg Since the content of the impurity elements P, O, and S is regulated so that is less than or equal to 0.6, Mg may be consumed by forming a compound with elements such as P, O, and S. It is suppressed, and the effect of improving strength and stress relaxation resistance due to Mg can be surely exerted.
In addition, since the formation of compounds of Mg and elements such as P, O, and S is suppressed, many compounds that are the starting points of fracture do not exist in the parent phase, and cold workability and bendability Can be improved.
Furthermore, since the electric conductivity is 95% IACS or more, it becomes possible to apply to the use where pure copper has been conventionally used.
Moreover, since the residual stress rate is 20% or more at 150° C. for 1000 hours, the stress relaxation resistance is particularly excellent, and permanent deformation can be suppressed to be small even when used in a high temperature environment. Therefore, it can be applied to a connector terminal or the like used in an automobile engine room or the like.

Here, in the rolled copper sheet of the present invention, the X-ray diffraction intensity from the {111} plane in the rolling plane is I{111}, and the X-ray diffraction intensity from the {200} plane is I{200}, {220}. X-ray diffraction intensity from the plane I{220}, X-ray diffraction intensity from the {311} plane I{311}, X-ray diffraction intensity from the {420} plane from I{420}, {220} plane When the ratio R{220} of the X-ray diffraction intensity of R{220}=I{220}/(I{111}+I{200}+I{220}+I{311}+I{420}) It is preferable that {220} is 0.2 or more.
The {220} plane is easily formed by rolling, and when the ratio of the {220} plane is high, excellent bending workability is obtained when bending is performed so that the bending axis is orthogonal to the rolling direction. Have. Therefore, bending workability can be improved by setting the ratio R{220} of the X-ray diffraction intensity from the {220} plane on the plate surface to 0.2 or more.

The electronic/electrical device component of the present invention is characterized by being formed of the above-mentioned rolled copper plate. The parts for electronic/electrical devices in the present invention include terminals such as connectors, relays, lead frames and the like.
The electronic/electrical device parts with this configuration are manufactured using a copper rolled plate with excellent electrical conductivity and stress relaxation resistance properties, so they can be applied to high-voltage applications and cracking during processing can occur. Is suppressed and it has excellent reliability.

ADVANTAGE OF THE INVENTION According to this invention, while being excellent in electroconductivity and stress relaxation resistance, the copper rolling board suitable for the components for electronic/electrical devices which can suppress the generation|occurrence|production of a defect, and the electronic/electrical equipment which consists of this copper rolling board Parts can be provided.

It is a flow figure of a manufacturing method of a copper rolling board which is this embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
The rolled copper sheet of this embodiment has a composition containing Mg in the range of 0.005 mass% to 0.05 mass% and the balance being Cu and inevitable impurities.
Further, in the rolled copper plate of the present embodiment, the content of H, which is an unavoidable impurity, is less than 1 massppm, the content of P is less than 10 massppm, the content of O is less than 5 massppm, and the content of S is less than 10 massppm. Therefore, the content of P, O, S and Mg has a relationship of (P+O+S)/Mg≦0.6 in mass ratio.
Further, the copper rolled sheet according to the present embodiment has characteristics that the electric conductivity is 95% IACS or more, the residual stress rate is 150° C., and 20% or more after 1000 hours.

Further, in the rolled copper plate of the present embodiment, the X-ray diffraction intensity from the {111} plane in the rolling plane is I{111}, and the X-ray diffraction intensity from the {200} plane is I{200}, {220. The X-ray diffraction intensity from the {} plane is I{220}, the X-ray diffraction intensity from the {311} plane is I{311}, and the X-ray diffraction intensity from the {420} plane is I{420}, {220} plane. When the ratio R{220} of the X-ray diffraction intensity from is R{220}=I{220}/(I{111}+I{200}+I{220}+I{311}+I{420}), R{220} is set to 0.2 or more.

In addition, in this embodiment, the plate thickness of the rolled copper plate is set to be in the range of more than 0.05 mm and 1.0 mm or less, preferably in the range of more than 0.1 mm and less than 1.0 mm.
Here, the reasons for defining the component composition, the electrical conductivity, the 0.2% proof stress, the residual stress rate, and the ratio R{220} of the X-ray diffraction intensity from the {220} plane as described above will be described below.

(Mg: 0.005 mass% or more and 0.05 mass% or less)
Mg is an element having the action and effect of improving the strength and the stress relaxation resistance property without significantly reducing the conductivity by forming a solid solution in the mother phase of copper. Further, by making Mg form a solid solution in the matrix, excellent bendability can be obtained.
Here, if the content of Mg is less than 0.005 mass%, the action and effect cannot be achieved successfully. On the other hand, when the Mg content exceeds 0.05 mass %, the conductivity may decrease.
For this reason, in the present embodiment, the Mg content is set within the range of 0.005 mass% or more and 0.05 mass% or less. The lower limit of the Mg content is preferably 0.007 mass% or more, and more preferably 0.01 mass% or more, in order to surely bring out the above-described effects.

(H (hydrogen): less than 1 massppm)
H is an element that causes blowhole defects in the ingot. This blow hole defect causes defects such as cracking during casting and swelling and peeling during rolling. It is known that defects such as cracks, blisters, and peeling deteriorate stress and stress corrosion cracking resistance since stress concentrates and becomes a starting point of fracture.
Particularly, in the case of a copper alloy containing Mg, MgO and H are formed by the reaction of Mg as a solute component with H ₂ O during melting. Therefore, when the vapor pressure of H ₂ O is high, a large amount of H may be dissolved in the molten metal, which leads to the above defects, so that it is necessary to strictly limit the content.
Here, if the H content exceeds 1 massppm, the above-mentioned blowhole defect is likely to occur.
Therefore, in the present embodiment, the H content is specified to be less than 1 mass ppm. In order to further suppress the occurrence of blowhole defects, the H content is more preferably less than 0.7 massppm, and further preferably less than 0.5 massppm.

(P (phosphorus): less than 10 massppm)
P is an element that is inevitably contained and reacts with Mg to form a crystallized substance during casting. Since this crystallized substance becomes the starting point of fracture, cracks are likely to occur during cold working and bending. Therefore, when the content of P is 10 mass ppm or more, many crystallized substances that are the starting points of fracture are present, and cold workability and bendability are deteriorated. Further, Mg reacts with P and is consumed, so that the amount of solid solution of Mg is reduced and strength and stress relaxation resistance may not be sufficiently improved.
For this reason, in the present embodiment, the P content is specified to be less than 10 massppm.

(O (oxygen): less than 5 massppm)
O is an element inevitably contained by mixing from the atmosphere or the like, and reacts with Mg to form an oxide. Since this oxide serves as a starting point of fracture, cracks easily occur during cold working and bending. Therefore, when the content of O is 5 mass ppm or more, there are many oxides that are the starting points of fracture, and the cold workability and bendability are reduced and the ductility is also reduced. Further, Mg reacts with O and is consumed, so that the amount of solid solution of Mg is reduced and strength and stress relaxation resistance may not be sufficiently improved.
For this reason, in the present embodiment, the O content is specified to be less than 5 massppm.
Further, in order to surely reduce the above-mentioned crystallized substances and oxides which are the starting points of fracture, it is more preferable that the total amount of P and O is less than 15 mass ppm.

(S (sulfur): less than 10 massppm)
S exists in the grain boundaries in the form of Mg sulfide, intermetallic compound, complex sulfide, or the like. Mg sulfides, intermetallic compounds, or composite sulfides present in the crystal grain boundaries cause grain boundary cracks during hot working and cause work cracking. Further, since Mg sulfide, intermetallic compound, or composite sulfide serves as a starting point of fracture, cracking is likely to occur during cold working or bending. Therefore, when the S content is 10 mass ppm or more, a large amount of Mg sulfides, intermetallic compounds or complex sulfides are present, and hot workability, cold workability, and bendability are deteriorated. In addition, Mg reacts with S and is consumed, so that the amount of solid solution of Mg is reduced and strength and stress relaxation resistance may not be sufficiently improved.
For this reason, in the present embodiment, the S content is specified to be less than 10 massppm.

(Mass ratio (P+O+S)/Mg≦0.6)
As described above, P, O, and S react with Mg to form a compound, which deteriorates cold workability, hot workability, and bendability. In particular, when the content of P, O, and S is large with respect to the added amount of Mg, the solid solution amount of Mg may decrease, and the strength and stress relaxation resistance may deteriorate.
Therefore, in the present embodiment, by defining the mass ratio (P+O+S)/Mg of the total content of P, O, and S and the content of Mg to be 0.6 or less, the amount of solid solution Mg is secured, and the strength is increased. And the stress relaxation resistance is sufficiently improved. Incidentally. In order to surely achieve this effect, the mass ratio (P+O+S)/Mg of the total content of P, O and S and the content of Mg is preferably 0.5 or less, and 0.4 or less. More preferably.

(Other unavoidable impurities: 0.1 mass% or less)
Other unavoidable impurities other than H, P, O and S include Ag, B, Ca, Sr, Ba, Sc, Y, rare earth elements, Ti, Zr, Hf, V, Nb, Ta and Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Se, Te, Rh, Ir, Ni, Pd, Pt, Au, Zn, Cd, Hg, Al, Ga, In, Ge, As, Sb, Examples thereof include Tl, Pb, Bi, Be, N, C, Sn, Si and Li. Since these unavoidable impurities have the effect of lowering the conductivity of the rolled copper plate, the total amount is made 0.1 mass% or less.
Further, Ag and Zn are easily mixed in copper and reduce the conductivity of the rolled copper plate, so that the total amount is preferably less than 500 mass ppm.
Furthermore, Si, Cr, Ti, Zr, Fe, Co, and Sn greatly reduce the conductivity in particular and deteriorate the bending workability due to the formation of inclusions. Therefore, the total amount of these elements should be less than 500 mass ppm. preferable.

(Conductivity: 95% IACS or more)
In the copper rolled sheet according to the present embodiment, when the electrical conductivity is 95% IACS or more, heat generation during energization is suppressed, and therefore, as an alternative to pure copper, for terminals such as connectors, relays, lead frames, and other electronic devices. Especially suitable for parts.

(0.2% proof stress in the direction orthogonal to the rolling direction: 300 MPa or more)
In the copper rolled plate of the present embodiment, when the 0.2% proof stress in the direction orthogonal to the rolling direction is 300 MPa or more, the copper rolled plate does not easily undergo plastic deformation in the direction orthogonal to the rolling direction. It is particularly suitable as a material for electronic equipment parts such as terminals such as connectors, relays, lead frames and the like.
The 0.2% proof stress in the direction orthogonal to the rolling direction is preferably 325 MPa or more, more preferably 350 MPa or more.

(Residual stress rate: 150%, 20% or more at 1000 hours)
In the copper rolled sheet according to the present embodiment, as described above, the residual stress rate is set to 20% or more at 150° C. for 1000 hours.
When the residual stress rate under this condition is high, permanent deformation can be suppressed to a small level even when used in a high temperature environment, and a decrease in contact pressure can be suppressed. Therefore, the rolled copper sheet according to the present embodiment can be applied as a terminal used in a high temperature environment such as around the engine room of an automobile.
The residual stress rate is preferably 40% or more at 150° C. for 1000 hours, and more preferably 50% or more at 150° C. for 1000 hours.

(Ratio of X-ray diffraction intensity from {220} plane R{220}: 0.2 or more)
When the {220} plane is increased on the plate surface of the copper rolled plate, excellent bending workability is obtained when the bending work is performed such that the bending axis is orthogonal to the rolling direction. Therefore, in this embodiment, R{220} is specified to be 0.2 or more. R{220} is preferably 0.25 or more, more preferably 0.3 or more.
On the other hand, if the {220} plane is excessively developed, the bending system deteriorates because the slip system is hard to operate when bending is performed such that the bending axis is parallel to the rolling direction. Therefore, in the present embodiment, the upper limit of R{220} is preferably 0.9 or less, and more preferably 0.8 or less.

Next, a method for manufacturing the copper rolled sheet of the present embodiment having such a configuration will be described with reference to the flowchart shown in FIG.

(Melting/casting process S01)
First, Mg is added to a copper melt obtained by melting a copper raw material to adjust the components, and a copper alloy melt is produced. Note that Mg can be added by using a simple substance of Mg, a Cu—Mg mother alloy, or the like. Further, the raw material containing Mg may be dissolved together with the copper raw material. Also, recycled materials and scrap materials of the present alloy may be used.
Here, the copper melt is preferably so-called 4NCu having a purity of 99.99 mass% or more, or so-called 5NCu having a purity of 99.999 mass% or more. In the melting process, in order to suppress the oxidation of Mg and to reduce the hydrogen concentration, the atmosphere is melted in an inert gas atmosphere (for example, Ar gas) with a low vapor pressure of H ₂ O, and the holding time during melting is minimal. It is preferable to keep the limit.
Then, the molten copper alloy having the adjusted components is poured into a mold to produce an ingot. In consideration of mass production, it is preferable to use the continuous casting method or the semi-continuous casting method.

(Homogenization/solution treatment step S02)
Next, heat treatment is performed for homogenizing and solutionizing the obtained ingot. Inside the ingot, there may be an intermetallic compound containing Cu and Mg as main components, which are generated by the segregation of Mg during the solidification process. Therefore, in order to eliminate or reduce these segregation and intermetallic compounds, a heat treatment of heating the ingot to 300° C. or higher and 900° C. or lower is performed to uniformly diffuse Mg in the ingot. , Mg may be dissolved in the mother phase. The heating step S02 is preferably performed in a non-oxidizing or reducing atmosphere.

Here, if the heating temperature is lower than 300° C., solution treatment may be incomplete, and a large amount of intermetallic compounds containing Cu and Mg as main components may remain in the mother phase. On the other hand, if the heating temperature exceeds 900° C., a part of the copper material may be in a liquid phase, and the texture and surface condition may be non-uniform. Therefore, the heating temperature is set in the range of 300°C to 900°C.
Note that hot working may be performed after the above-described homogenization/solution treatment step S02 in order to increase the efficiency of rough rolling and homogenize the structure described later. 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 adopted. The hot working temperature is preferably in the range of 300°C or higher and 900°C or lower.

(Rough processing step S03)
Roughing is performed in order to form a predetermined shape. The temperature condition in the roughing step S03 is not particularly limited, but in order to suppress recrystallization or to improve dimensional accuracy, it is cold or warm rolling within a range of -200°C to 200°C. Is preferable, and room temperature is particularly preferable. The processing rate is preferably 20% or more, more preferably 30% or more. The processing method is not particularly limited, and for example, rolling, wire drawing, extrusion, groove rolling, forging, pressing and the like can be adopted.

(Intermediate heat treatment step S04)
After the roughing step S03, heat treatment is performed for softening for improving workability or for forming a recrystallized structure.
The method of heat treatment is not particularly limited, but short-time heat treatment in a continuous annealing furnace is preferable from the effect of reducing manufacturing cost. For example, it is preferable to hold the temperature at 400° C. for about 1 to 120 seconds.
The rough processing step S03 and the intermediate heat treatment step S04 may be repeatedly performed.

(Finishing rolling step S05)
Finish rolling is performed in order to process the copper material after the intermediate heat treatment step S04 into a predetermined shape or to increase the {220} plane formed by rolling. The temperature condition in the finish rolling step S05 is not particularly limited, but in the range of -200°C to 200°C, which is cold rolling or warm rolling to suppress recrystallization or softening. Is preferably used, and room temperature is particularly preferable. Further, the rolling rate is appropriately selected so as to approximate the final shape, but in order to improve the strength by work hardening or increase the {220} plane, it should be 20% or more. preferable. Also. In order to further improve the strength and increase the {220} plane, it is more preferable to set the rolling rate to 30% or more.

(Finishing heat treatment step S06)
Next, a finish heat treatment is performed on the plastically worked material obtained in the finish rolling step S05 to remove residual strain.
The heat treatment temperature is preferably in the range of 100° C. or higher and 800° C. or lower. In this finishing heat treatment step S06, it is necessary to set the heat treatment conditions (temperature, time, cooling rate) so as to avoid a significant decrease in strength and R{220} due to recrystallization. For example, it is preferable to keep the temperature at 250° C. for about 1 to 120 seconds. This heat treatment is preferably performed in a non-oxidizing atmosphere or a reducing atmosphere.
The method of heat treatment is not particularly limited, but short-time heat treatment in a continuous annealing furnace is preferable from the effect of reducing manufacturing cost.
Further, the finish rolling step S05 and the finish heat treatment step S06 may be repeatedly performed.

In this way, the rolled copper plate of this embodiment is produced.
The electronic/electrical device component according to the present embodiment is manufactured by subjecting the above-mentioned rolled copper plate to punching, bending, and the like.

According to the copper rolled sheet of the present embodiment configured as described above, it has a composition containing Mg in the range of 0.005 mass% or more and 0.05 mass% or less, and the balance of Cu and inevitable impurities. Therefore, Mg can be solid-dissolved in the mother phase of copper, and the strength and stress relaxation resistance can be improved without significantly reducing the conductivity. Specifically, since the electric conductivity is 95% IACS or more, it can be applied to the use where a pure copper material is conventionally used.

Further, since the content of H, which is an impurity element that is unavoidably mixed in the rolled copper plate, is specified to be less than 1 massppm, the occurrence of defects such as cracks, swelling, and peeling due to blowhole defects is suppressed. It becomes possible.

Further, regarding P, O, and S, which are impurity elements unavoidably mixed in the rolled copper plate, the P content is less than 10 massppm, the O content is less than 5 massppm, and the S content is less than 10 massppm. Since the contents of P, O, S and Mg have a mass ratio of (P+O+S)/Mg≦0.6, Mg produces elements such as P, O and S and compounds. By doing so, the consumption can be suppressed, and the effect of improving the strength and the stress relaxation resistance characteristic of Mg can be surely exerted. Further, it is possible to suppress the formation of compounds of Mg and elements such as P, O and S, and improve the cold workability and bending workability.

Further, in the rolled copper plate of the present embodiment, the X-ray diffraction intensity from the {111} plane in the rolling plane is I{111}, and the X-ray diffraction intensity from the {200} plane is I{200}, {220. The X-ray diffraction intensity from the {} plane is I{220}, the X-ray diffraction intensity from the {311} plane is I{311}, and the X-ray diffraction intensity from the {420} plane is I{420}, {220} plane. When the ratio R{220} of the X-ray diffraction intensity from is R{220}=I{220}/(I{111}+I{200}+I{220}+I{311}+I{420}), Since R{220} is 0.2 or more, it has excellent bending workability when bending is performed so that the axis of bending is orthogonal to the rolling direction.

Further, in the copper rolled sheet according to the present embodiment, the residual stress rate is set to 20% or more at 150° C. for 1000 hours, so that the permanent deformation can be suppressed to be small even when used in a high temperature environment. it can.
Furthermore, in the copper rolled sheet according to the present embodiment, since the 0.2% proof stress in the direction orthogonal to the rolling direction is 300 MPa or more, it is not easily plastically deformed, and terminals such as connectors, relays, It can be used as a material for electronic/electrical device parts such as lead frames.

Further, since the electronic/electrical device component of the present embodiment uses the above-mentioned copper rolled plate as a material, it has excellent conductivity, strength, bending workability, and stress relaxation resistance, and is suitable for high-voltage applications. It is also applicable to, the occurrence of cracks during processing is suppressed, and it has excellent reliability.

Although the rolled copper plate and the electronic/electrical device component according to the embodiment of the present invention have been described above, the present invention is not limited to this, and may be appropriately performed without departing from the technical idea of the invention. Can be changed.
For example, in the above-described embodiment, an example of a method for manufacturing a copper rolled plate has been described, but the method for manufacturing a copper rolled plate is not limited to this embodiment, and an existing manufacturing method is appropriately selected and manufactured. May be.

Below, the result of the confirmation experiment conducted to confirm the effect of the present invention will be described.
Inventive Examples 1 to 4, Reference Examples 5 to 14 and Comparative Examples 1, 2, 4 to 8, H is less than 2 massppm, P is less than 20 massppm, O is less than 10 massppm, and S is less than 20 massppm Purity 99.99 mass% The copper raw material which consists of the above pure copper was prepared. In Reference Examples 15 and 16, a copper raw material made of pure copper having a purity of 99.9 mass% or more in which H is less than 2 massppm, P is less than 20 massppm, O is less than 10 massppm, and S is less than 20 massppm is prepared. In Comparative Example 6, tough pitch copper was used as the copper raw material.

These copper raw materials were charged in a high-purity graphite crucible and were subjected to high frequency melting in an atmosphere furnace in an Ar gas atmosphere. Mg was added to the obtained molten copper to prepare the component composition shown in Table 1, which was poured into a carbon mold to produce an ingot.
At this time, in Reference Examples 11 and 14 and Comparative Examples 4 and 5, Cu-P mother alloy was added. In Reference Examples 13 and 14 and Comparative Example 7, a Cu-S master alloy was added. In Reference Examples 10, 12 and 14, ingots were produced by introducing a small amount of O ₂ into the atmosphere during melting. In Reference Example 10 and Comparative Example 3, steam was introduced into an Ar gas atmosphere to perform high frequency melting.
The size of the ingot was about 110 mm thick×about 110 mm wide×about 250 mm long.

A surface of 2 mm or more near the casting surface was chamfered from the obtained ingot, and a block of 100 mm × 200 mm × 100 mm was cut out.
This block was heated in an Ar gas atmosphere under the temperature conditions shown in Table 2 for 4 hours for homogenization/solution treatment.

Then, after performing rough rolling under the conditions shown in Table 2, heat treatment was performed using a salt bath under the temperature conditions shown in Table 2.
The heat-treated copper material was appropriately cut into a shape suitable for the final shape, and surface grinding was performed to remove an oxide film. Then, at room temperature, finish rolling was carried out at the rolling rate shown in Table 2 to produce a thin plate having a thickness of 0.25 mm, a width of about 200 mm and a length of 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 prepare a thin plate for property evaluation.
The total amount of unavoidable impurities was 0.01 to less than 0.05 mass% except for Reference Examples 15 and 16. The total amount of inevitable impurities in Reference Examples 15 and 16 was 0.06 to 0.07 mass %.

(Cold workability evaluation)
As an evaluation of workability, the presence or absence of edge cracks was observed during the rough rolling and finish rolling described above. If there is no or almost no visible ear cracks, ⊚; if small ear cracks with a length of less than 1 mm occur, ○; if cracks with a length of 1 mm or more and less than 3 mm occur, △, length: 3 mm The case where the above-mentioned large edge cracks occurred was marked with x, and the case where the edge cracks were severe and the rolling was stopped halfway was marked as xx.
The length of the edge crack is the length of the edge crack extending from the widthwise end of the rolled material toward the widthwise center.

(X-ray diffraction intensity)
The X-ray diffraction intensity from the {111} plane on the plate surface is I{111}, the X-ray diffraction intensity I{200} from the {200} plane, the X-ray diffraction intensity I{220} from the {220} plane, { The X-ray diffraction intensity I{311} from the 311} plane, the X-ray diffraction intensity I{331} from the {331} plane, and the X-ray diffraction intensity I{420} from the {420} plane are set as follows. It was measured at.
A measurement sample was taken from the characteristic evaluation strip, and the X-ray diffraction intensity around one rotation axis was measured for the measurement sample by the reflection method. Cu was used as the target, and Kα X-rays were used. The tube current is 40 mA, the tube voltage is 40 kV, the measurement angle is 40 to 150°, and the measurement step is 0.02°. In the profile of the diffraction angle and the X-ray diffraction intensity, after removing the background of the X-ray diffraction intensity, The integrated X-ray diffraction intensity I was calculated by combining Kα1 and Kα2 of the peaks from the diffraction plane.
Then, from R{220}=I{220}/(I{111}+I{200}+I{220}+I{311}+I{331}+I{420}), X from the {220} plane on the plate surface The ratio R{220} of the line diffraction intensity was calculated. The measurement site of the X-ray diffraction intensity was the central portion in the width direction of the sample plate.

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

(Number of breaks in tensile test)
Tensile tests were performed 10 times using the above No. 13B test pieces, and the number of breaks in the tensile test pieces in the elastic region before reaching the yield point was taken as the number of breaks in the tensile test for measurement. The elastic region refers to a region that satisfies a linear relationship in the stress-strain curve. The greater the number of breaks, the lower the workability due to defects and inclusions.

(Bending workability)
Bending was performed according to the four test methods of Japan Copper and Brass Association technical standard JCBA-T307:2007. A plurality of test pieces with a width of 10 mm and a length of 30 mm were sampled from the thin plate for characteristic evaluation so that the axis of bending was orthogonal to the rolling direction, and the bending angle was 90 degrees and the bending radius was 0.25 mm (R/ A W bending test was performed using a W type jig with t=1).
When cracks are observed visually by observing the outer peripheral portion of the bent portion, ``X'' is judged, when large wrinkles are observed, Δ is judged, and when fractures or fine cracks or large wrinkles cannot be confirmed, judgment is made as ○. It was In addition, ◯ and Δ were judged to be acceptable bending workability.

(conductivity)
A test piece having a width of 10 mm and a length of 150 mm was sampled from the characteristic evaluation strip, and the electrical resistance was determined by the four-terminal method. The dimension of the test piece was measured using a micrometer, and the volume of the test piece was calculated. Then, the conductivity was calculated from the measured electric resistance value and the volume. The test piece was sampled so that its longitudinal direction was perpendicular to the rolling direction of the characteristic evaluation strip.

(Stress relaxation property)
In the stress relaxation resistance test, stress was applied by a method according to the cantilever beam method of the Japan Copper and Brass Association technical standard JCBA-T309:2004, and the residual stress rate after holding for 1000 hours at a temperature of 150° C. was measured. ..
As a test method, a test piece (width 10 mm) was taken from each characteristic evaluation strip in a direction orthogonal to the rolling direction, and the initial flexural displacement was adjusted so that the maximum stress on the surface of the test piece was 80% of the proof stress. The span length was adjusted by setting it to 2 mm. The maximum surface stress is defined by the following equation.
Maximum surface stress (MPa)=1.5 Et δ ₀ /L _s ²
However,
E: Young's modulus (MPa)
t: Thickness of sample (t=0.25 mm)
δ ₀ : Initial deflection displacement (2 mm)
L _s : Span length (mm)
Is.

The residual stress rate was measured from the bending tendency after holding for 1000 hours at a temperature of 150° C., and the stress relaxation resistance was evaluated. The residual stress rate was calculated using the following formula.
Residual stress rate (%)=(1-δ _t /δ ₀ )×100
However,
δ _t : Permanent deflection displacement after holding at 150°C for 1000 hours (mm)-Permanent deflection displacement after holding at room temperature for 24 hours (mm)
δ ₀ : Initial deflection displacement (mm)
Is.

(Measuring method of content of Mg and impurity element)
Mg was measured by using an inductively coupled plasma optical emission spectrometer (ICP-AES).
The analysis of H and N was carried out by the thermal conductivity method, and the analysis of O, S and C was carried out by the infrared absorption method. Other unavoidable impurities were measured using a glow discharge mass spectrometer (GD-MS).
The measurement was carried out at two locations, the center of the sample and the end in the width direction, and the one with the higher content was defined as the content of the sample.

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

In the conventional example and the comparative example 1, the amount of Mg was less than the range of the present invention, and the strength and the residual stress rate were insufficient.
In Comparative Example 2, the amount of Mg was larger than the range of the present invention, and the conductivity was insufficient.
In Comparative Example 3, the amount of H was larger than the range of the present invention, the edge cracks occurred during cold rolling, and the tensile test was performed 10 times, and as a result, the tensile test pieces in the elastic region were broken 4 times. However, deterioration of workability due to defects was recognized.
In Comparative Examples 4 and 5, the amount of P was larger than the range of the present invention, and large cracks occurred during cold rolling. Therefore, the subsequent evaluation was stopped.
In Comparative Example 6, the amount of O was larger than the range of the present invention, the edge cracks occurred during cold rolling, and the tensile test was performed 10 times, resulting in the tensile test pieces breaking 4 times in the elastic region. However, deterioration of workability due to inclusions was observed.
In Comparative Example 7, the amount of S was larger than the range of the present invention, and a large edge crack occurred during cold rolling. Therefore, the subsequent evaluation was stopped.
In Comparative Example 8, the mass ratio (P+O+S)/Mg was larger than that of the present invention, and the strength and residual stress rate were insufficient.

On the other hand, in the inventive examples, the electrical conductivity was high and the stress relaxation resistance was excellent.
From the above, it was confirmed that according to the present invention, it is possible to provide a rolled copper plate which is excellent in conductivity and stress relaxation resistance and which is suitable for parts for electronic/electrical devices.

Claims (3)

Mg in the range of 0.005 mass% or more and 0.05 mass% or less, with the balance being Cu and inevitable impurities,
The content of H is less than 1 massppm, the content of P is less than 10 massppm, the content of O is less than 5 massppm, the content of S is less than 10 massppm, and the total amount of P, O and S (P+O+S) and the mass of Mg. The ratio (P+O+S)/Mg is set to 0.6 or less, and
Conductivity is 95% IACS or more,
Residual stress rate is 20% or more at 150° C. for 1000 hours,
The number of ruptures in the tensile test, which is the number of ruptures in the tensile test piece in the elastic range before the yield point is reached by performing the tensile test 10 times using the No. 13B test piece specified in JIS Z 2241, is less than 1 time. A rolled copper plate characterized by the above. The X-ray diffraction intensity from the {111} plane in the rolled surface is I{111}, the X-ray diffraction intensity from the {200} plane is I{200}, and the X-ray diffraction intensity from the {220} plane is I{220}. , The X-ray diffraction intensity from the {311} plane is I{311}, the X-ray diffraction intensity from the {420} plane is I{420}, and the ratio R{220} of the X-ray diffraction intensity from the {220} plane is When R{220}=I{220}/(I{111}+I{200}+I{220}+I{311}+I{420}), R{220} is 0.2 or more. The rolled copper plate according to claim 1, wherein A component for electronic/electrical equipment, comprising the rolled copper plate according to claim 1 or 2.

Images