JP4601063B2 - High strength and high conductivity copper alloy, copper alloy spring material and copper alloy foil, and method for producing high strength and high conductivity copper alloy - Google Patents

Description

  The present invention relates to a high-strength high-conductivity copper alloy, a copper alloy spring material, a copper alloy foil, and a method for producing a high-strength high-conductivity copper alloy.

Spring materials for electrical and electronic equipment such as terminals, connectors, switches, and relays are required to have excellent spring characteristics, bending workability, and electrical conductivity. Conventionally, phosphor bronze has been used. High-strength, high-conductivity alloys have been developed due to the demand for further miniaturization.
In general, when a strengthening element is added to Cu to increase the strength, the electrical conductivity decreases, while on the other hand, increasing the Cu purity to increase the electrical conductivity has a relationship of decreasing the strength. Therefore, an alloy system (double phase alloy) in which the second phase is crystallized in the Cu matrix has been developed. In this alloy, the second phase is dispersed in a fiber shape by strong processing, and since the parent phase is Cu while having a strength equal to or higher than that of phosphor bronze, the conductivity is 60% IACS (international).
high electrical conductivity exceeding an annealed copper standard (ratio of electrical conductivity to annealed standard annealed copper) is obtained. As this multiphase alloy system, Cu—Cr, Cu—Fe, Cu—Nb, Cu—W, Cu—Ta, Cu—Ag, and the like are known (for example, see Patent Documents 1 to 8).

  In the case of the above prior art, means such as drawing and rolling are used as a processing method for drawing the second phase into a fiber shape. For example, in Patent Documents 1 and 2 below, when a multi-phase alloy is rolled and manufactured, the second phase is sufficiently stretched in the rolling direction to become fibrous, and the rolling proceeds in the direction perpendicular to the rolling direction (the longitudinal direction of the rolled material). It also describes that the strength of the rolled material is also improved.

In addition, rolling is a processing method capable of continuously producing various plate materials and the like, but there is a problem that the degree of processing cannot be increased so much due to restrictions on material dimensions before and after processing. That is, the processing degree is expressed by true strain η = ln (A ₀ / A) (A ₀ : cross-sectional area before processing, A: cross-sectional area after processing), but the plate thickness decreases as the processing degree increases. Therefore, when the product thickness is reached, further processing becomes impossible. For example, the processing degree of a normal rolled material is only about η = 1 to 6 (63.2% to 99.75%), and a material before processing having a very large dimension is required to obtain a larger η. This is necessary, and the strength of the multiphase alloy cannot be improved.
For this reason, repeated roll-bonding (Accumulative Roll-Bonding: hereinafter referred to as “ARB” as appropriate) has been proposed (see, for example, Patent Document 9). This technique is a method of performing strong processing by rolling without reducing the final plate thickness by repeating the cycle of re-rolling after laminating the material after rolling to the original plate thickness after cutting. .

JP-A-6-192801 JP-A-6-279894 JP-A-9-104935 JP-A-9-235633 Japanese Patent Laid-Open No. 9-249925 JP-A-10-53824 Japanese Patent Laid-Open No. 10-140267 Japanese Patent Publication No. 48-34652 Japanese Patent No. 2961263

In general, a dual-phase alloy is an alloy that is strengthened by using a composite rule, or an alloy that is strengthened by increasing the area of a heterogeneous interface, and is strengthened by dispersing the second phase in a fiber form (fiber form). The Here, it is made by dispersing the crystallized second phase that does not dissolve in copper into a fibrous form by strong processing in the copper matrix phase, and the effect of increasing the area of the heterophase interface is great. For this reason, the strength of the second phase increases as the number of the second phase is more dispersed (finely dispersed if the volume fraction is the same), the second phase is more easily stretched, and the degree of processing is increased.
The above-described conventional multiphase alloys are all two-phase alloys, and include Cu-bcc alloys such as Cu-Fe alloys, Cu-Cr alloys, Cu-Nb alloys, and Cu-Ag alloys (eutectic alloys). ). However, although Cu-Ag alloy tends to make initial crystallized fine, it is inferior in hot workability and heat resistance, and has a high material cost. On the other hand, the Cu—Fe alloy is superior in heat resistance as compared to the Cu—Ag alloy, and the material cost is low.

However, for example, as an Fe raw material of a Cu—Fe alloy, mild steel (C ≦ 0.004, Si ≦ 0.04, Mn: 0.10 to 0.60, P ≦ 0.035, S ≦ 0.040, Cu ≦ 0.08, Al ≦ 0.080, N ≦ 0.0100) and cast iron scrap material, etc., the material cost is low, but it adheres to C and scrap contained in mild steel There is a problem that impurities (C, S, etc.) contained in the oil are mixed into the alloy. C and S are often distributed in the Fe phase (second phase) in the Cu-Fe alloy, and the second phase becomes difficult to deform when the alloy is rolled, so the dispersion strengthening of the second phase is not sufficient. However, the strength does not improve.
In particular, if the second phase, which is difficult to deform, remains in a coarse state up to the final plate thickness, it causes pinholes when processed into foil.

On the other hand, in the case of a multiphase alloy, the strength increases as the cold work degree increases from the strengthening mechanism. However, in cold rolling, there are cases where there is a limit to the degree of work that can be reached because the final thickness is determined. The degree of work is determined by the initial plate thickness before rolling and the required final plate thickness, and is usually about the degree of work η = 1 to 6 (63.2% to 99.75%). Therefore, if the workability can be improved while ensuring the final thickness, the strength of the Cu—Fe alloy can be increased.
That is, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a high-strength and highly-conductive copper alloy excellent in both strength and conductivity and a method for producing the same.

  As a result of various studies, the present inventors have found that the strength can be improved without impairing conductivity by reducing the amount of C and S in the Cu-Fe alloy.

In order to achieve the above object, the high-strength and highly-conductive copper alloy of the present invention contains Fe in a mass ratio of 7% to 20%, the total amount of C and S is 0.004% or less, the remaining Cu and Ri Do unavoidable impurities, further containing less than 3% and not more than 0.05% of Ag, consisting of a second phase and Cu matrix phase containing Fe 70% or more.
It is preferable the total amount of C and S of the second phase is less than 0.05%.

The copper alloy spring material of the present invention is formed by rolling the high-strength and high-conductivity copper alloy, and when viewed from the cross-section perpendicular to the rolling, the average aspect ratio At ₂ of the second phase satisfies 10 ≦ At ₂ . Excellent bending workability.

The copper alloy foil of the present invention is formed by rolling the high-strength, high-conductivity copper alloy, and when viewed from a cross section perpendicular to the rolling, the average aspect ratio At ₂ of the second phase satisfies 10 ≦ At ₂ and is flexible. Is excellent.

Here, the aspect ratio of the Fe phase is defined by (Extension width of Fe phase) / (Thickness of Fe phase in the rolling thickness direction). Therefore, the aspect ratio At viewed from the cross section along the direction perpendicular to the rolling (the cross section perpendicular to the rolling) is represented by t2 / t1 in FIG. t2 and t1 can be obtained from a cross-sectional image of the Fe phase. For the t2 and t1 in the Fe phase, the maximum values of t2 and t1 may normally be adopted from the BSE (reflected electron) image of the SEM (scanning electron microscope) obtained for the cross section perpendicular to the rolling.
The At is calculated from one t2 of Fe phase, t1 measured for Fe phase plurality (e.g., 100), the average value of the obtained At may be set to the average aspect ratio At _2.

  One form of the manufacturing method of the high strength high conductivity copper alloy of the present invention includes a first step of laminating two or more rolling materials of the high strength high conductivity copper alloy, and the laminating direction of the laminated rolling materials. And the second step of rolling to the above are repeated one or more times in this order.

  According to the present invention, a high-strength, high-conductivity copper alloy excellent in both strength and conductivity can be obtained.

  Hereinafter, embodiments of the high-strength, high-conductivity copper alloy according to the present invention will be described. In the present invention, “%” means “% by mass” unless otherwise specified.

<Composition of high strength and high conductivity copper alloy>
[Chemical composition]
The copper alloy contains Fe in a mass ratio of 7% to 20%, the total amount of C and S is 0.004% or less, and the remainder is Cu and inevitable impurities.

[Two-phase alloy]
When Fe is contained in an amount of 7% or more, it is crystallized as an Fe phase in the Cu matrix. Therefore, the copper alloy of the present invention is composed of a two-phase alloy of an Fe phase (second phase) and a Cu parent phase. The Fe phase contains 70% or more of Fe, and contributes to the strengthening accompanying an increase in the area of the heterophase interface as a multiphase alloy. If the Fe content in the alloy is less than 7%, the effect of composite strengthening by the Fe phase is small, and if it exceeds 20 %, the melting point rises and the solid-liquid coexistence temperature range increases, making casting difficult. As a result, the productivity is lowered, and the conductivity of the obtained alloy is lowered.
The Fe phase crystallizes, for example, in a needle shape in the Cu matrix, but the crystallization form is not limited to this. C and S described below are distributed at a predetermined ratio between the Cu matrix and the Fe phase. In addition, although Cu parent phase contains 90% or more of Cu, for example, it is not restricted to this.
The Fe phase can be observed as a composition different from the parent phase by SEM BSE image after polishing the cross section of the rolled structure after the final process. If the structure is difficult to observe, etching or electropolishing may be performed.

[Inevitable impurities]
The content of inevitable impurities in the copper alloy does not have to be as clean as oxygen-free copper C1011 standardized in JIS H2123. In addition, “substantially consisting of the remaining Cu and inevitable impurities” means a range that is normally mixed from other components (including known components), for example, furnace materials and raw materials, as long as the effects of the present invention are not impaired. It shows that it may contain the component of.

[C and S]
In the copper alloy, the total amount of C and S is 0.004% or less. When the total amount of C and S exceeds 0.004%, a large amount of C and S is contained in the Fe phase, and the Fe phase is difficult to be deformed during processing, and the effect of the multiphase alloy is insufficient and the strength is improved. do not do. C and S are considered to be mixed when scrap materials (soft steel, cast iron, etc.) are used as Fe raw materials, for example.
On the other hand, Mn, Al, and the like contained in the scrap material and the like do not affect the characteristics of the copper alloy of the present invention as long as they are ordinary amounts. For example, the Mn content may be less than 0.001% and the Al content may be less than 0.002%.
For example, as content of various components in the copper alloy of the present invention, C 0.001%, S 0.002%, P 0.001%, Pb less than 0.001%, Zn 0.002%, Sn 0. Examples include less than 001%, Si 0.005%, Al 0.002%, and Mn less than 0.001%.

  C and S are not uniformly distributed in the alloy, but are distributed in a large amount in the Fe phase, and this tendency does not change even when heat treatment or the like is performed. Therefore, in order to facilitate the deformation of the Fe phase, it is necessary to reduce the amounts of C and S in the Fe phase. However, by reducing the C and S of the entire alloy, the C and S in the Fe phase are reduced. Can also be reduced. Therefore, the total amount of C and S in the Fe phase is preferably 0.05% or less, more preferably 0.02% or less. The total amount of C and S can usually be an average value of the total amount measured for a plurality of Fe phases present in the structure.

  As a method of managing the total amount of C and S within the above range, decarburization and desulfurization are performed when melting the molten alloy, carbon is prevented from entering from the melting furnace during melting, and homogenization annealing is sufficiently performed. To do.

The analysis of the contents of C and S contained in the entire alloy can use a combustion infrared absorption method. The analysis may use the final product (for example, rolled material or foil) of the copper alloy of the present invention, or may use an ingot that is a material before the Fe phase is greatly deformed. If it is an ingot etc., the analysis of C and S is easier.
Analysis of C and S contained in the Fe phase can be performed as follows. First, a copper alloy sample is immersed in a mixed solution of ammonia, hydrogen peroxide, and water. Next, only the Fe phase is extracted from the Cu—Fe multiphase alloy by a method such as filtering the solution or removing the Fe phase adhering to the sample surface. Then, the C and S contents of the extracted Fe phase are analyzed by a combustion infrared absorption method. Here, sufficient care must be taken so that impurities other than Fe, such as dust and dirt, do not enter the extracted Fe phase.

[Ag and Sn]
Furthermore, in the said copper alloy, it is preferable to contain 0.05 to 3% of Ag and / or Sn in a total amount. The trace element strengthens the copper alloy by precipitation strengthening (or solid solution strengthening), improves heat resistance, or refines the initial crystallized product of the Fe phase during the casting of the copper alloy, thereby improving the strength of the alloy. If the total amount of Ag and / or Sn is less than 0.05%, these effects are not sufficient, and if it exceeds 3%, the conductivity may be lowered. Ag is present in the Cu matrix and contributes to precipitation strengthening and solid solution strengthening, and Sn is considered to contribute to solid solution strengthening. Both Ag and Sn contribute to heat resistance and Fe phase refinement. Sn contributes more to heat resistance than Ag.

<Rolling high-strength, high-conductivity copper alloy>
By rolling the alloy material (such as an ingot), the strength of the alloy can be further improved. In general, a multi-phase alloy is an alloy that is strengthened by dispersing a phase different from the matrix, such as a fiber or ribbon, in the matrix, and crystallized without being dissolved in Cu by strong processing. The Fe phase is stretched and dispersed in the Cu matrix to obtain high strength. Strong processing includes drawing, rolling, and the like, but when rolled, wide materials and plate materials can be produced.

<Reinforcing mechanism of Cu-Fe alloy>
By the way, the strength of the multiphase alloy of the present invention has an elastic effect and a plastic effect, and the elastic effect is strengthened by the presence of a phase harder than the parent phase. According to the composite side, the formula σ = V ₁ σ ₁ + V ₂ σ ₂
(Subscripts 1 and 2 indicate Cu and Fe, respectively, V indicates a volume fraction, and σ indicates stress). However, in the case of the alloy of the present invention, V ₁ is much larger than V _2. For example, when V ₁ = 0.8 and V ₂ = 0.1, even if the stress σ _{2 of the} Fe phase is increased to 100 MPa, As a whole alloy, the strength increases only by 10 MPa.
On the other hand, the plastic effect is an effect caused by deformation only in the Cu matrix, and the strength is increased when the area of the heterophase interface between the Cu matrix and the Fe phase increases.
From the above, it is more important in terms of increasing the strength to increase the area of the heterogeneous interface than to increase the strength (stress) σ of the Fe phase.

  When the structure before rolling is the same, the area of the heterophase interface increases when the Fe phase is greatly stretched by rolling. Although both the Cu mother phase and the Fe phase are stretched by rolling, since the Cu mother phase is more easily deformed, the Fe phase is not stretched as much as the Cu mother phase. When C and S are contained in the Fe phase, the Fe phase hardens rapidly, and thus it is difficult to be further stretched.

First, when a rolled material is considered as the alloy of the present invention, the structure shown in FIG. 1 is exemplified as the rolled material structure. In this figure, the Fe phase 4 is dispersed in the Cu matrix (matrix) of the rolled material 2. The sheet width direction is defined as “rolling perpendicular direction T”, and the longitudinal direction of the sheet is defined as “rolling direction L”. In the case of a conventional multiphase alloy, the second phase is hardly drawn in the direction perpendicular to the rolling and is in the form of a fiber. On the other hand, in the present invention, the Fe phase is also stretched in the direction perpendicular to the rolling direction and exhibits, for example, a ribbon shape (tongue piece shape).
Thus, in the case of a rolled material, the ribbon-like Fe phase is dispersed in a state of being laminated in the rolling surface direction, and since the thickness of the Fe phase is thin, the spacing between the phases (when viewed from the rolling surface direction, Fe The smaller the thickness of the Cu matrix phase separated by the phases, the larger the number of Fe phases in the unit volume of the alloy, that is, the area of the heterogeneous interface increases.

<Average aspect ratio At ₂ of Fe phase>
When the rolled material of the present invention is viewed from a cross section perpendicular to the rolling, the average aspect ratio At ₂ of the Fe phase is set to 10 or more. A method for adjusting the average aspect ratio At ₂ will be described with reference to FIG.
As described above, in the present invention, the Fe phase is also stretched in the direction perpendicular to the rolling direction, and exhibits, for example, a ribbon shape (tongue piece shape). In addition, in other conventionally known multi-phase alloys, even if there is a case where there is a ribbon-like (tongue piece-like) shape in which the second phase is stretched also in the direction perpendicular to the rolling direction, in the present invention, Preferably, the length in the direction perpendicular to the rolling direction of the second phase is longer than that of the conventional double phase alloy, and the average aspect ratio is also larger in the present invention.

[Regulation range of At ₂ ]
In the present invention, At ₂ is 10 or more. When At ₂ is less than 10, the Fe phase is not stretched in the direction perpendicular to the rolling direction, the strength in this direction is insufficient and the strength is not improved, and cracking occurs at the interface between the different phases. Decreases. On the other hand, At ₂ does not have an upper limit, but if At ₂ is 110 or less, production is easy. In addition, in a normal rolling method, it may be difficult to obtain At ₂ exceeding 80, but in ARB (repeated lap bonding rolling) described later, it is easy.

[Method for adjusting At ₂ ]
Usually, when rolling is performed, the structure is stretched in the rolling direction, but not so much in the direction perpendicular to the rolling direction. Therefore, in consideration of the value of At ₂ finally managed, there is a method of growing a crystallized product (Fe phase) to a certain size before rolling so that the width t2 of the Fe phase extends in the direction perpendicular to the rolling. is there. Furthermore, hot forging, At ₂ increases by performing width out by cold forging. In addition, by lowering the rolling direction tension during rolling, the structure in the rolling direction can be weakened to extend the Fe phase in the direction perpendicular to the rolling direction, the degree of processing per pass can be reduced, and the number of passes can be increased. The Fe phase can be stretched in the direction perpendicular to the rolling.

  For example, first, hot forging is performed to widen the width to about 1.4 times the ingot width. Thereafter, hot rolling and cold rolling are performed, and heat treatment, cold rolling, and heat treatment are performed again.

Next, cold rolling is performed after the heat treatment, and in order to increase At ₂ , the degree of work η per pass during cold rolling η = 0.16 to 0.36 (15% to 30%), preferably η = 0.29 (25%) or less, and the tension applied during cold rolling is 80 to 300 MPa, preferably 200 MPa or less.

<Manufacturing>
Hereafter, an example of the manufacturing method of the alloy of this invention is given. First, electrolytic copper or oxygen-free copper is used as a main raw material, and Fe and Ag and / or Sn are melted in a melting furnace to produce an ingot (ingot) having a predetermined composition. After this ingot is homogenized and annealed, it is subjected to hot (warm) rolling or hot (warm) forging or hot (warm) rolling and hot (warm) forging, and cold rolling.
As a rolling method, the final plate thickness may be obtained by the above-described cold rolling, but ARB can also be performed. When performing by ARB, it is preferable to carry out as follows.

<Repeated lap joint rolling (ARB)>
ARB performs the above-described cold rolled material as a rolled material for ARB. FIG. 2 is a process diagram schematically showing an example of an ARB.
In this figure, first, the surfaces S and S of the two rolled materials 1A and 1B are respectively cleaned. As the rolling material, a copper alloy ingot, a material obtained by appropriately homogenizing and annealing the ingot, and then hot rolling or hot forging, or a cold rolled material can be used. The thickness of the rolled material may be a thick material such as an ingot, or a cold rolled material having a thin plate thickness close to the final product thickness. The cleaning is for removing oil, oxide film, and the like on the surface so that the rolled materials are joined by rolling. For example, degreasing, polishing, washing, and the like can be performed. In the ARB, a cleaning process is currently essential, but it can be omitted in the future if the surface roughness of the rolled material can be strictly controlled by annealing, rolling, or the like.
Next, the rolling materials 1A and 1B are stacked (I: first step), and the tip portions J are joined together. Any number of rolled materials may be stacked as long as it is two or more. Joining is not essential, but it is preferably performed to prevent the tip portion from being opened during rolling to prevent joining, or the formation of a gap between the laminated materials to cause surface oxidation or the like. In addition to welding, the joining method may be mechanical joining (fastening with a bolt or the like, binding with a wire or the like). Further, in addition to the front end, the rear end (rolling side) of the rolled material may be joined.
Next, the rolling raw materials 1A and 1B are passed between the rolls 10 and 10, and rolled in the stacking direction (vertical direction in the figure) (II: second step). Depending on the workability of the rolled material, the rolled material may be heat-treated before rolling or may not be heat-treated.
Next, using the cutter 20, the rolled material 1 </ b> C is cut in, for example, the short direction (the direction perpendicular to the rolling direction) to obtain two rolled materials 1 </ b> D and 1 </ b> E whose longitudinal directions are divided. Each rolled material is subjected to ARB again and rolled in the same manner as the rolled material.
In the present invention, various heat treatments and annealing may be performed before and after rolling, in the middle thereof, and after final rolling.

In ARB, the series of steps described above are repeated one or more times in this order. When repeating twice or more, the process which cut | disconnects a rolling material and returns to the beginning of a process is performed. For example, when the reduction rate of ARB is 50%, if the thickness of the rolled material before rolling is t ₀ , the thickness of the rolled material 1C after rolling is also t ₀ (0.5t ₀ + 0.5t ₀ ), It can be rolled without reducing the actual material thickness. Further, when the distance between the Fe phases 1x (the thickness of the Cu parent phase) in the rolled materials 1A and 1B in FIG. 2 is d ₀ , the thickness of the Cu parent phase after rolling is d ₁ = 0.5d ₀ (the reduction ratio). 50%), it can be seen that the structure of the rolled material undergoes strong processing and becomes finer.

As described above, the alloy of the present invention can be strengthened by increasing the area of the heterogeneous interface. Considering such a strengthening mechanism, as the degree of work η is increased by rolling with ARB, the distance between the Cu matrix phases decreases and the thickness decreases, and the area of the heterophase interface between the Cu matrix and the Fe phase increases. Increased strength. As the number of repetitions of ARB increases, the degree of processing can be increased. Moreover, although there is no upper limit to the number of repetitions, it may be set within a range in which cracking due to rolling does not occur according to the composition of the alloy. Depending on the necessary final plate thickness, for example, the number of repetitions is about 4 to 5 times. In particular, the final product thickness of the rolled material is determined in advance, and in normal rolling, the rolling degree cannot be increased beyond this thickness. However, according to ARB, even after processing to less than the final product thickness, it becomes thicker by superimposing, so that the degree of processing can be increased by repeating ARB.
In addition, if the rolling reduction per rolling in ARB is 50%, the thickness of the rolled material after n times of repetition becomes 1/2 ⁿ of the thickness of the rolled material. Therefore, when the number of repetitions is 4 and 5, respectively, the processing degrees are η = 2.77 (93.8%) and 3.47 (96.9%), respectively.

  In addition, when heat-treating the rolled material before ARB, if the Fe phase of the rolled material is kept at a temperature below the temperature at which it is divided by heat, strength deterioration due to the division of the second phase can be prevented and ductility can be recovered. Cracks are less likely to occur, making it easier to join.

  Conventionally, rolled materials of copper-based multiphase alloys cannot be used for spring materials such as terminals due to problems such as electrical conductivity. It has been used as a product part. In the present invention, it is possible to obtain a copper alloy having both good conductivity and strength, good bending workability as a spring material, and good flexibility as a metal foil, and downsizing and weight reduction of electronic devices. And can greatly contribute to the improvement of the performance, and the effects are extremely effective in the industry.

  In addition, this invention is not limited to the said embodiment. Moreover, as long as there exists an effect of this invention, the copper alloy in the said embodiment may contain another component.

The present invention can be applied to electronic devices such as connectors. As for the connector, the terminal is comprised by the manufacturing method of the said high intensity | strength highly conductive copper alloy. The connector can be applied to any known form and structure, and usually consists of a male (plug) and a female (jack). For example, the terminals may be arranged like a spring, with a number of skewered pins arranged side by side and appropriately bent so that the terminals come into electrical contact with each other when fitted to other connectors.
The present invention is also applicable to foil.

  EXAMPLES Next, although an Example is given and this invention is demonstrated further in detail, this invention is not limited to these.

1. Sample preparation Using electrolytic copper and mild steel scrap (with oil), if necessary, adding Ag and / or Sn and melting in vacuum. After copper and mild steel melt, oxidation consumption, vapor pressure of added elements In view of the above, the ingot having the composition shown in Table 1 was cast by holding for 40 min or more in a vacuum of 1 Pa or less. If necessary, the molten metal was decarburized with oxygen and then deoxidized. The ingot was subjected to homogenization annealing and hot rolling (or hot forging), and then cold rolling and annealing were repeated. In addition, about the comparative example, after melt | dissolving a raw material, hot water was discharged simultaneously with reaching predetermined temperature (melting | fusing point +100 degreeC), and the ingot of the composition shown in Table 1 was cast.
The cold rolling was performed in the following manner as usual cold rolling or ARB. The annealing temperature was adjusted to a temperature at which the second phase stretched by the cold rolling is not divided by the heat treatment. If annealing is performed after rolling, cracks are less likely to occur during subsequent rolling.
In addition, the total work degree of the normal cold rolling was set to η = 5.0 (99.3%) or more for the spring material and η = 6.5 (99.85%) or more for the foil. The final plate thickness was 0.1 mm and 0.2 mm for the spring material, and 20 μm and 50 μm for the foil.

1-1. Examples 1-9, Comparative Examples 1-9
The rolling material is degreased, polished, and washed during the cold rolling to clean the surface, then annealed at a temperature below the temperature at which the Fe phase is divided by heat, and cold rolled until the final thickness is reached. 1 pass processing was performed while adjusting the tension. For comparison, samples prepared in the same manner by adding elements having the compositions shown in Table 1 were designated as Comparative Examples 1 to 9. The homogenization annealing of each example was performed at 850 ° C. × 180 minutes, and the homogenization annealing of the comparative example was performed at 850 ° C. × 60 minutes.
1-2. Examples 10-12
The rolled material was degreased, polished, and washed during the cold rolling to clean the surface, and then annealed at a temperature below which the Fe phase was divided by heat. Next, rolled materials of the same thickness were stacked, a total of four locations at the front and rear corners were welded, and ARB was performed with the number of repetitions of 2 or 3 times, or a final sheet thickness was obtained without performing it (working degree) η exceeded 6 (99.75%)). A sample of the example was obtained as described above. The homogenization annealing of each example was performed at 850 ° C. × 180 minutes.

2. Evaluation of sample (1) Content of C and S The analysis of the content of C and S contained in the entire alloy was performed on samples (ingots and plate materials with a thickness of 10 mm during production). Since no ingot or plate material was analyzed, the combustion infrared absorption method was used. As an analyzer, a CS444 type manufactured by LECO was used.
For analysis of C and S contained in the Fe phase, first, a copper alloy sample (similar to the above, an ingot or a plate material having a thickness of 10 mmt) was immersed and dissolved in a mixed solution of ammonia, hydrogen peroxide, and water. The solution was then filtered and the residual Fe phase was extracted. Then, the C and S contents in 500 mg of the extracted Fe phase were analyzed in the same manner as described above by the combustion infrared absorption method.

(2) Calculation of the average aspect ratio At ₂ of the Fe phase After polishing the rolled perpendicular section of the sample (spring material or foil) after rolling to the final thickness after ARB (1 μm diamond paste, but the Fe phase is small and difficult to observe) In the case after electropolishing), a BSE image was obtained using SEM. In the image, the black portion compared with the Cu parent phase was regarded as the Fe phase, and the thickness t1 and the extension width t2 of the Fe phase were determined. t1 and t2 take the maximum value of each Fe phase. Seeking At from the t1, t2 measured in the image, each seeking At about 100 Fe phase was adopted as the averaged as the average aspect ratio At _2. Since the back scattering coefficient increases as the atomic number increases, the Fe phase appears black compared to the Cu phase in the BSE image.

(3) Measurement of strength According to JIS Z2241, a tensile test of the sample in the rolling parallel direction was performed to obtain 0.2% yield strength (YS: yield strength). The sample was produced according to JIS.
(4) Measurement of conductivity The conductivity of the sample was determined by the four probe method.

(5) Bending workability Each sample was subjected to a W bending test in accordance with JIS H3110 and H3130, and a minimum bending radius (MBR) of a 10 mm wide sample (t: sample thickness) extending in the direction perpendicular to the rolling direction and the rolling parallel direction, respectively. Asked. And bending workability was evaluated according to the following criteria.
○: MBR / t ≦ 2.5 x: MBR / t> 2.5 (6) Flexibility For each sample, each sample was subjected to MIT flex test according to ASTM D2176 (JIS C6471). The IPC bending test was performed in accordance with IPC standard TM-650 (reference drawing of JIS C6471), and the flexibility was evaluated according to the following criteria.
○: even without breaking bent more than 100 times in the MIT bending test, and × as not to break even when bent over 10 ^four times in IPC flex test: breaking when bent at times of less than 10 ⁴ times the IPC bending test Or fractured when bent less than 100 times in the MIT flex test

  The obtained results are shown in Tables 1 and 2.

<About Table 1>
As is clear from Table 1, Examples 1 to 8 were excellent in strength, conductivity, and workability (bending workability and bendability). Here, the sample processed into the spring material was excellent in bending workability, and the sample processed into foil was excellent in flexibility. From the above, it is clear that the total amount of C and S in the alloy is 0.004% or less and the average aspect ratio At ₂ of the second phase is 10 or more.
Although the total amount of C and S in the alloy was 0.004% or less, in Example 9 where the average aspect ratio At ₂ of the second phase was less than 10, the strength and conductivity were excellent, Inferior in properties (bending workability and flexibility). However, since the strength and conductivity of Example 9 are superior to those of Comparative Example 9 having the same composition, it can be sufficiently used for applications that do not require workability (bending workability and flexibility).
According to FIG. 3 showing the structure of the sample after rolling of the alloy shown in Example 4, it was found that the Fe phase was stretched and the area of the heterogeneous interface was increased, and the strength of this alloy was improved.

On the other hand, in the case of Comparative Examples 1 to 9 in which the total amount of C and S in the alloy exceeded 0.004% for each example having almost the same component system, workability (bending processing) in addition to strength and conductivity Inferiority and flexibility). According to FIG. 4 showing the structure of the sample after rolling of the alloy shown in Comparative Example 5, it can be seen that the Fe phase is not stretched and a coarse Fe phase exists.
Moreover, many pinholes were seen about the foil of each comparative example.
<About Table 2>
As is clear from Table 2, Examples 10 to 12 were excellent in strength, conductivity, and workability (bending workability and bendability). Here, the sample processed into the spring material was excellent in bending workability. From the above, it is clear that the total amount of C and S in the alloy is 0.004% or less and the average aspect ratio At ₂ of the second phase is 10 or more.
In the case of Example 12 in which ARB was not performed, the strength was slightly reduced as compared with Examples 10 and 11 having almost the same component system, but there was no practical problem. From this, it was found that the strength was further improved by performing ARB and increasing the degree of processing.

It is the figure which showed typically the rolling material structure | tissue of the alloy of this invention. It is process drawing which showed the outline of an example of ARB typically. It is a figure which shows the structure | tissue of the sample after rolling of the alloy shown in an Example. It is a figure which shows the coarse Fe phase in the structure | tissue of the sample after rolling of the alloy shown to a comparative example.

Explanation of symbols

1A, 1B Rolled material J Rolled material tip 10 Roll 1C, 1D, 1E, 2 Rolled material 1x, 4 Fe phase

Claims (5)

Mass ratio of Fe contained 20% less than 7% or more, the total amount of C and S 0.004% or less, Ri Do the balance Cu and unavoidable impurities, contains more than 3% 0.05% or more of Ag, A high-strength, highly conductive copper alloy comprising a second phase containing 70% or more of Fe and a Cu matrix. The high strength and high conductivity copper alloy according to claim 1 , wherein the total amount of C and S in the second phase is 0.05% or less. A copper alloy spring material made by rolling a high-intensity and high conductivity copper alloy according to claim 1 or 2, When viewed from perpendicular to the rolling section, an average aspect ratio At ₂ of the second phase is 10 ≦ At A copper alloy spring material excellent in bending workability satisfying ₂ . A copper alloy foil obtained by rolling the high-strength, high-conductivity copper alloy according to claim 1 or 2 , wherein an average aspect ratio At ₂ of the second phase is 10 ≦ At ₂ when viewed from a cross section perpendicular to the rolling. A copper alloy foil with excellent flexibility that satisfies this requirement. A first step of laminating two or more rolled materials of the high-strength, highly conductive copper alloy according to claim 1 or 2 and a second step of rolling the laminated rolled materials in the laminating direction in this order. A method for producing a high-strength, high-conductivity copper alloy that is repeated one or more times.