JP6542817B2 - Copper alloy for electronic materials - Google Patents

Description

  The present invention relates to a Cu-Co-Ni-Si-based alloy which is a precipitation-hardening copper alloy suitable for use in various electronic parts, and in particular, can improve dimensional stability at the time of pressing. It proposes a technology.

  Copper alloys for electronic materials used in various electronic components such as connectors, switches, relays, pins, terminals, lead frames etc. are required to have both high strength and high conductivity (or thermal conductivity) as basic characteristics Be done. And, in recent years, high integration, miniaturization, and thinning of electronic parts have rapidly progressed, and the requirements for copper alloys used for electronic parts have been further advanced along with this.

  From the viewpoint of high strength and high conductivity, the amount of use of the precipitation hardening copper alloy is increasing instead of the conventional solid solution strengthened copper alloy represented by phosphor bronze, brass and the like as a copper alloy for electronic materials . In the precipitation hardening type copper alloy, when the solution-processed supersaturated solid solution is subjected to an aging treatment, the fine precipitates are dispersed uniformly, and the strength of the alloy becomes high, and at the same time, the amount of solid solution elements in copper decreases. Electrical conductivity is improved. For this reason, it is possible to obtain a material which is excellent in mechanical properties such as spring property and is also excellent in electrical conductivity and thermal conductivity.

Among precipitation-hardened copper alloys, Cu-Ni-Si alloys generally referred to as corson alloys are representative copper alloys having relatively high conductivity, strength, and bending workability, and are currently used in the art. It is one of the alloys under active development. In this copper alloy, strength and conductivity can be improved by precipitating fine Ni-Si based intermetallic compound particles in a copper matrix.
In such Corson alloys, a Cu-Co-Si alloy in which Co is added or Ni is replaced by Co has been proposed for the purpose of further improving the properties.

  The Cu-Co-Si-based alloy generally has a high solution temperature as compared to the Cu-Ni-Si-based alloy, and it is difficult to refine crystal grains after solution treatment. On the other hand, in the patent documents 1-3 etc., the technique which controls a crystal grain by a Cu-Co-Si type alloy is described.

Specifically, in Patent Document 1, it is described that crystal grains are refined by performing an aging treatment prior to solution treatment, focusing on the improvement of bendability and the improvement of variations in mechanical characteristics. There is. Further, Patent Document 2 discloses that the average grain size is controlled by adjusting the finish temperature of the hot rolling and the processing degree of the final pass of the intermediate rolling to improve the plating property. Furthermore, Patent Document 3 describes that the bendability is improved by controlling the crystal orientation of the Cube orientation.
Such a Cu-Co-Si alloy is generally manufactured by melt-casting an ingot and sequentially performing hot rolling, first cold rolling, solution treatment, aging treatment and final cold rolling.

JP 2012-72470 A JP 2011-252216 A JP, 2013-32564, A

  By the way, with the recent miniaturization and thinning of electronic parts, for example, in the connector incorporated therein, the distance between adjacent pins to be arranged (so-called pitch) and the width of terminals become extremely narrow, and the thickness also becomes thin. There is a tendency.

  When the Cu-Co-Si alloy of the prior art as described above is pressed to produce such a small connector, the pitch fluctuates greatly at the time of pressing, and for example, the pins are vertically moved from the target dimensions. There was a problem that it moved to the left and right and deformed. That is, by controlling the crystal grain size as in the prior art, the dimensional stability of pressing could not be significantly improved. Such deterioration in product dimensions greatly reduces the yield in the assembly process.

  In particular, as a connector material having a narrow pitch and a long spring length represented by a floating connector, a Corson alloy having excellent properties such as strength and conductivity is often employed. As described above, there is a need for an effective measure against the problem that the dimension of the pin is not stable at the time of pressing.

  An object of the present invention is to solve such a problem, and its object is to have a 0.2% proof stress and conductivity suitable for use in an electronic material, and to press it into a connector shape or the like. It is an object of the present invention to provide a copper alloy for electronic materials which can improve the dimensional stability at the time of production.

  As a result of intensive investigations, the inventor controlled X-ray diffraction by controlling grain size and orientation in a Cu-Co-Ni-Si alloy in which a part of Co of a Cu-Co-Si alloy is substituted with Ni. The X-ray diffraction integral intensities from the {200} crystal plane, the {220} crystal plane, and the {311} crystal plane measured by the method satisfy the predetermined relationship, whereby It has been found that the dimensions can be stabilized. And such control of the crystal grain size and the crystal orientation is performed by performing solution treatment twice under predetermined conditions between the first cold rolling and the aging treatment in the conventional manufacturing process, and further, those solutionizing New findings have been obtained that can be realized by performing intermediate rolling under predetermined conditions during processing.

Under the above findings, the copper alloy for electronic materials according to the present invention comprises 0.5 to 3.0% by mass of Co, 0.1 to 2.0% by mass of Ni, 0.1 to 1.5% by mass of A copper alloy for electronic materials that contains Si, has a mass ratio of (Ni + Co) / Si of 3.0 to 5.0 , and the balance is Cu and unavoidable impurities, and has a 0.2% proof stress in the rolling parallel direction Is 630 MPa or more, conductivity is 50% IACS or more, and the average crystal grain size in the rolling parallel section is 10 to 20 μm (however, except 10 μm) , X-ray diffraction integral intensity I from {200} crystal plane on the surface The {200}, the X-ray diffraction integral intensity I {220} from the {220} crystal plane, and the X-ray diffraction integral intensity I {311} from the {311} crystal plane are (I {220} + I {311) }) / I {200} 5.0 5.0 is satisfied.

  The copper alloy for electronic materials of the present invention preferably has a mass ratio of Ni to Co (Ni / Co) of 0.1 to 2.0.

  It is preferable that the copper alloy for electronic materials of this invention has a Langford value r of 1.0 or more. Here, r is represented by r = (r0 + 2 × r45 + r90) / 4, where r0 is the Lankford value in the rolling direction, r45 is the Lankford value 45 ° from the rolling direction, and r90 is the Lankford value in the sheet width direction. .

The copper alloy for electronic materials of the present invention is parallel to the rolling plane from the 0.2% proof stress of the direction parallel to the rolling direction, the 0.2% proof stress obtained by subtracting the 0.2% proof stress of the direction perpendicular to the direction parallel to the rolling direction The difference is preferably 50 MPa or less.

The copper alloy for electronic materials of the present invention, a {200} X-ray diffraction integrated intensity I {200} from the crystal plane at the surface, a standard pure copper powder X-ray diffraction析積partial intensity I ₀ {200} but, I { It is preferable to satisfy the relationship of 200} / I ₀ {200} ≦ 1.0.

The copper alloy for electronic materials of the present invention can further contain Cr at 0.5% by mass or less.
Further, it further contains Zn and Sn at 1.0 mass% or less respectively, Mg, P, Ca and Mn at maximum 0.2 mass% or less respectively, and these are selected from Zn, Sn, Mg, P, Ca and Mn The total of at least one or more of them may be 2.0 mass% or less.

  According to the copper alloy for electronic materials of the present invention, the X-ray diffraction integral intensity I {200} from the {200} crystal plane at the surface, and the X-ray diffraction integral intensity I {220} from the {220} crystal plane The dimensional accuracy after pressing by satisfying the relationship of (I {220} + I {311}) / I {200} ≧ 5.0 with the X-ray diffraction integral intensity I {311} from the {311} crystal plane Can be effectively enhanced. This makes it possible to improve the yield when manufacturing the electronic material.

It is a schematic diagram which shows roughly the torn surface and shear surface which were formed in the press fracture surface by evaluation of the pressability in an Example.

Hereinafter, embodiments of the present invention will be described in detail.
The copper alloy for an electronic material according to one embodiment of the present invention comprises 0.5 to 3.0% by mass of Co, 0.1 to 2.0% by mass of Ni, and 0.1 to 1.5% by mass of Si. Containing by mass ratio (Ni + Co) / Si of 3 to 5, the balance being copper and unavoidable impurities, 0.2% proof stress in the rolling parallel direction is 630 MPa or more, conductivity is 50% IACS or more, The X-ray diffraction integral intensity I {200} from the {200} crystal plane on the surface, and the X-ray diffraction integral intensity I from the {220} crystal plane, having an average crystal grain size of 10 to 20 μm determined in the rolling parallel section The {220} and the X-ray diffraction integral intensity I {311} from the {311} crystal plane satisfy the relationship of (I {220} + I {311}) / I {200} ≧ 5.0.

(Addition amount of Co, Ni, Si)
Co, Ni and Si are precipitated as Ni ₂ Si or Co ₂ Si by appropriate aging treatment, and the strength of the alloy is increased. At the same time, the conductivity is increased because Co, Ni and Si dissolved in the matrix are reduced by precipitation. In addition, undissolved Co during solution treatment serves as a pinning effect of grain boundaries, contributes to the refinement of crystal grains, and improves the pressability. However, on the other hand, when the amount of Ni is small and the amount of Co is too large, the crystal grains become smaller than a predetermined range, which causes deterioration of deep drawability. In addition, since Co-Si based precipitates are easily coarsened due to their high precipitation ability, the coarse precipitates may adversely affect the pressability if the amount of Co is too large. In order to make pressability and deep drawability compatible, the addition amounts of Co, Ni and Si are controlled within a predetermined range.
When the addition amount of Co and Si is less than 0.5% by mass and less than 0.1% by mass, respectively, desired strength can not be obtained, while Co: more than 3.0% by mass, Si: 1 If the content is more than 5% by mass, high strength can be achieved, but the conductivity is significantly reduced and the hot workability is further deteriorated. Therefore, the addition amount of Co and Si is set to 0.5 to 3.0% by mass of Co and 0.1 to 1.5% by mass of Si. Preferably, 1.0 to 2.5% by mass of Co and 0.3 to 1.0% by mass of Si are used.
When the addition amount of Ni is less than 0.1% by mass, the crystal grain size becomes smaller than the predetermined range, and the deep drawability is deteriorated. On the other hand, if it exceeds 2.0% by mass, the conductivity will be lowered. Therefore, the addition amount of Ni is 0.1 to 2.0% by mass, preferably 0.3 to 1.8% by mass.

Co, Ni and Si have (Ni + Co) / Si of 3 to 5 by mass ratio. With the ratio, it is possible to improve both the strength and the conductivity after precipitation hardening. If the ratio is less than 3, precipitation of Ni ₂ Si or Co ₂ Si in the aging treatment becomes insufficient, and the strength decreases. When the ratio exceeds 5, Ni and Co which do not precipitate as Ni ₂ Si or Co ₂ Si form a solid solution in the matrix phase, and the conductivity decreases.

(Ni to Co concentration ratio (Ni / Co))
The mass ratio Ni / Co is 0.1 to 2.0. By setting it in this range, it is possible to control the crystal grain size within a predetermined range and achieve both pressability and deep drawability. When the ratio of Co is increased (the ratio of Ni is reduced), the average crystal grain size becomes smaller than the predetermined range, and the deep drawability is deteriorated. On the other hand, when the ratio of Ni is increased (the ratio of Co is decreased), the average crystal grain size is larger than the predetermined range, and the pressability is deteriorated. Ni / Co is set to 0.1 to 2.0, preferably 0.2 to 1.0.

(Cr addition amount)
Cr preferentially precipitates on grain boundaries in the cooling process during melt casting, so that the grain boundaries can be strengthened, cracking during hot working is less likely to occur, and yield loss can be suppressed. That is, although Cr precipitated at grain boundaries during melt casting re-dissolves by solution treatment or the like, during subsequent aging precipitation, it forms a compound with precipitated particles of bcc structure mainly composed of Cr or Si. Of the amount of added Si in a conventional Cu-Co-Ni-Si alloy, Si that does not contribute to aging precipitation suppresses the increase in conductivity while remaining solid-solved in the matrix, but is a silicide-forming element By further depositing Cr by adding Cr, the amount of solid solution Si can be reduced, and the conductivity can be increased without losing the strength. However, if the Cr concentration exceeds 0.5% by mass, coarse second phase particles are likely to be formed, which impairs product properties. Therefore, in the present invention, Cr can be added at a maximum of 0.5% by mass. However, if the amount is less than 0.03% by mass, the effect is small, so it is preferable to add 0.03 to 0.5% by mass, more preferably 0.09 to 0.3% by mass.

(Addition amount of Sn and Zn)
Also in Sn and Zn, the addition of a small amount improves the product characteristics such as strength, stress relaxation characteristics and plating property without losing the conductivity. The effect of the addition is mainly exhibited by solid solution in the matrix phase. However, when each concentration of Sn and Zn exceeds 1.0% by mass, the property improvement effect is saturated and the productivity is impaired. Therefore, in the present invention, Sn and Zn can be added up to 1.0% by mass each. However, since the effect is small if the total of Sn and Zn is less than 0.05% by mass, the total of Sn and Zn is preferably 0.05 to 2.0% by mass, more preferably 0.5 to 1.0. It can be mass%.

(Addition amount of Mg, P, Ca and Mn)
Mg, P, Ca and Mn, when added in a small amount, improve product characteristics such as strength and stress relaxation characteristics without losing conductivity. The effect of the addition is exhibited mainly by solid solution in the matrix phase, but it is possible to exhibit further effects by being contained in the second phase particles. However, when each concentration of Mg, P, Ca and Mn exceeds 0.5%, the property improvement effect is saturated and the productivity is impaired. Therefore, in the present invention, Mg, P, Ca and Mn can be added up to 0.2 mass% at the maximum. However, since the effect is small when the total of Mg, P, Ca and Mn is less than 0.01% by mass, the total of Mg, P, Ca and Mn is preferably 0.01 to 0.5% by mass, more preferably May be 0.04 to 0.2% by mass.

  When containing Zn, Sn, Mg, P, Ca, and Mn described above, the total of at least one or more selected from Zn, Sn, Mg, P, Ca, and Mn is 2.0 mass% or less . When the total exceeds 2.0% by mass, the property improvement effect is saturated, and the productivity is deteriorated.

(0.2% proof stress)
In order to satisfy the characteristics required for a predetermined electronic material such as a connector, the 0.2% proof stress in the rolling parallel direction is set to 630 MPa or more. The 0.2% proof stress in the rolling parallel direction is preferably in the range of 630 MPa to 950 MPa, more preferably 680 to 950 MPa.

Further, it is preferable that a difference of 0.2% proof stress obtained by subtracting 0.2% proof stress in the rolling perpendicular direction from 0.2% proof stress in the rolling parallel direction is 50 MPa or less. This can further improve the dimensional stability at the time of pressing. That is, if the difference in 0.2% proof stress is too large, the pins of the connector may be easily deformed in the vertical and horizontal directions at the time of pressing, and the dimensional accuracy may be reduced. From this point of view, it is desirable that the difference in 0.2% proof stress be as small as possible. Specifically, the difference is more preferably 30 MPa, and even more preferably 20 MPa.
0.2% proof stress is measured according to JIS Z2241 using a tensile tester.

(conductivity)
Conductivity shall be 50% IACS or more. Thereby, it can be effectively used as an electronic material. The conductivity can be measured in accordance with JIS H0505. The conductivity is preferably 55% IACS or more.

(Average grain size)
By reducing the crystal grain size, high strength can be obtained, and in particular, by reducing the crystal grain size in the rolled parallel section, it is possible to contribute to the improvement of dimensional stability at the time of pressing. Therefore, the average grain size of the rolling parallel cross section is set to 10 to 20 μm. When the average crystal grain size exceeds 20 μm, the pressability deteriorates. On the other hand, when the average crystal grain size is less than 10 μm, the Rankford value r decreases and the deep drawability deteriorates. From this viewpoint, the average crystal grain size is preferably 10 to 20 μm.
The average grain size is measured based on JIS H0501 (cutting method).

(Integrated intensity of X-ray diffraction)
The copper alloy for electronic materials of the present invention has X-ray diffraction integral intensity I {200} from {200} crystal plane on the surface (rolled surface) determined by X-ray diffraction method (XRD) and {220} crystal plane X-ray diffraction integral intensity I {220} and X-ray diffraction integral intensity I {311} from the {311} crystal plane, (I {220} + I {311}) / I {200} 5.0 5.0 Meet the relationship. Thereby, the dimensional stability after pressing can be improved. This is thought to be due to the fact that the slip system of the material differs depending on the crystal orientation, and it is believed to affect the formation of a fractured surface during pressing, but is not limited to such a theory.
For this reason, (I {220} + I {311}) / I {200} is preferably 5.0 or more, and more preferably 6.0 or more. Although the upper limit is not particularly provided, less than 10.0 is preferable.

In this invention, a {200} X-ray diffraction integrated intensity I {200} from the crystal plane at the surface, a standard pure copper powder X-ray diffraction析積partial intensity I ₀ {200} but, I {200} / I ₀ It is preferable to satisfy the relationship of {200} ≦ 1.0. This is because when the strength of I {200} / I ₀ {200} is high, the pressability is deteriorated. Since the {200} crystal face is easier to deform than other orientations, it is thought that the crystal grains including the {200} crystal face are preferentially deformed during pressing, and the pressability of the polycrystalline copper alloy is degraded .
On the other hand, if the ratio of I {200} / I ₀ (200) is too small, unrecrystallization may remain in part of the metal structure, which may deteriorate the pressability.
Therefore, the ratio of I {200} / I ₀ (200) is preferably 0.1 or more and 1.0 or less, and more preferably 0.2 or more and 0.7 or less.
The X-ray diffraction integral intensity can be measured by using a predetermined X-ray diffractometer.

(Production method)
The Cu-Co-Ni-Si alloy as described above is a process of melt casting an ingot, a hot rolling process, a first cold rolling process, a first solution treatment process, and a second cold rolling process. The second solution treatment step, the aging treatment step of heating the material temperature to 450 ° C. to 550 ° C., and the final cold rolling step can be sequentially performed. In addition, after hot rolling, it is possible to carry out facing as needed.

  Specifically, first, raw materials such as electric copper, Co, Ni, Si and the like are melted using an air melting furnace or the like to obtain a molten metal having a desired composition. Then, the molten metal is cast into an ingot. Thereafter, hot rolling is performed, first cold rolling, first solution treatment, second cold rolling, second solution treatment, aging treatment (2 to 20 hours at 450 to 550 ° C.), final cold rolling (Processing degree 5 to 50%) is performed. After final cold rolling, strain relief annealing may be performed. The strain relief annealing can be performed usually at 250 to 600 ° C. for 5 to 300 seconds in an inert atmosphere such as Ar. After the second solution treatment, final cold rolling and aging treatment may be performed in this order, and the order of these steps may be switched.

Here, in this manufacturing method, it is important to perform first solution treatment, second cold rolling and second solution treatment under predetermined conditions after the first cold rolling. In the prior art, since these processes were not performed, and a single solution treatment was performed after hot rolling, it was not possible to obtain the crystal grains as in the present invention, and the dimensional stability after pressing was increased. It did not improve significantly.
In the following, each step of the first solution treatment, the second cold rolling and the second solution treatment will be mainly described in detail. In addition, it is possible to set it as the conditions normally employ | adopted in the manufacturing process of a Cu-Co-Ni-Si type-alloy other process.

The first solution treatment is performed at a material temperature of 900 to 1000 ° C. As a result, solid solution of Co, Ni, and Si progresses, and the crystal grains after the second solution treatment are refined to a predetermined size, and the crystal orientation as described above can be controlled. If this temperature is less than 900 ° C., the above-mentioned solid solution does not proceed, so the crystal grains become coarse. On the other hand, if it exceeds 1000 ° C., it is difficult to control the crystal orientation because the solid solution proceeds too much. It becomes.
In general, the texture of the copper alloy is influenced by the amount of solid solution and the state of precipitation before final solution treatment, so the first solution treatment becomes important. The first solution treatment can be performed for 15 seconds to 300 seconds. If this time is too long, the balance between solid solution and precipitation will be poor, and control of the texture will be difficult. If it is too short, solid solution will not proceed and the crystal grains will be coarsened.

  The second cold rolling after the first solution treatment is also performed for the purpose of controlling the crystal grain size and the crystal orientation. For this purpose, the working degree of the second cold rolling is 15 to 30%. If this degree of processing is less than 15%, coarsening of crystal grains is caused, while if it is more than 30%, the crystal grain size becomes smaller than a predetermined range, and the crystal orientation does not satisfy the above definition. there is a possibility.

Furthermore, it is preferable that arithmetic mean roughness Ra of the material surface after this 2nd cold rolling shall be 0.2 micrometer or more from a viewpoint of strength improvement of a rolling perpendicular direction, and a dimensional accuracy improvement after a press. That is, by thus controlling the arithmetic mean roughness Ra of the material surface after the second cold rolling, the 0.2% proof stress in the rolling perpendicular direction in finish rolling is improved, and the pressability is improved. It is from. This is because the emissivity of the material changes due to the surface roughness becoming rough, but it does not appear in (I {220} + I {311}) / I {200}, but after the second solution treatment The 0.2% proof stress in the direction perpendicular to the rolling is improved by improving the balance by optimizing the balance and increasing the strain applied to the material by increasing the friction of the material surface during finish rolling, and the pressability is improved. Although it is considered that it is not limited to such a theory.
This arithmetic mean roughness Ra is the roughness of the material surface after the second cold rolling determined based on JIS B0601 (2001). In order to realize such surface roughness Ra, the roll surface of the second cold rolling can be improved.

After the second cold rolling, a second solution treatment is performed. The second solution treatment can be performed at a material temperature of 850 ° C. to 1000 ° C. If the temperature is lower than 850 ° C., the solution is insufficient to cause a decrease in strength, and if the temperature is higher than 1000 ° C., the growth of recrystallized grains is caused to increase the size of the crystal grains.
The time of the second solution treatment can be 15 seconds to 60 seconds. If the time of the second solution treatment is too long, recrystallized grains will be caused to cause growth of crystal grains, the crystal grains become large and the pressability deteriorates, and when too short, the crystal grain size becomes smaller than a predetermined range, and the deep drawability deteriorates. there is a possibility.

  In addition, since the temperature of the aging treatment is lower than 450 ° C., the conductivity is lowered, and the temperature is higher than 550 ° C., so that the strength is lowered. In addition, the working ratio of final cold rolling is 5% or more because the required strength can not be obtained if it is too low. On the other hand, there is no particular upper limit, but generally 50% or less to prevent deterioration of bendability. It can be done.

  The Cu-Co-Ni-Si alloy of the present invention can be processed into various copper products such as plates, strips, tubes, rods and wires, and further, the Cu-Co-Ni-Si copper alloy is And electronic components such as lead frames, connectors, pins, terminals, relays, switches, and foils for secondary batteries. In particular, high dimensional accuracy can be obtained at the time of pressing when manufacturing the connector.

  Next, since the copper alloy for electronic materials of this invention was made as an experiment and the performance was confirmed, it demonstrates below. However, the description herein is for the purpose of illustration only and is not intended to be limiting.

The copper alloy having the component composition shown in Table 1 was melted at 1300 ° C. using a high frequency melting furnace, and cast into a 30 mm thick ingot. Subsequently, after heating this ingot at 1000 degreeC for 2 hours, it hot-rolled to plate | board thickness 10 mm, and the hot rolling completion temperature was 900 degreeC. After completion of the hot rolling, the material was cooled in water at an average cooling rate of 18 ° C./s when the material temperature decreased to 850 ° C. to 400 ° C., and then left in air for cooling. And in order to remove the scale of the surface, it was chamfered to thickness 9 mm, and it was set as the board of thickness 0.15 mm by cold rolling. Thereafter, the first solution treatment, the second cold rolling, the second solution treatment and the aging treatment were sequentially carried out under the conditions shown in Table 1 to produce test pieces. In the second cold rolling, the surface roughness Ra of the material was controlled by changing the surface roughness of the roll.
The following characteristic evaluation was performed to each test piece obtained in this way. The results are shown in Table 2.

<Strength>
Each test piece is subjected to a tensile test in each direction parallel to rolling and perpendicular to rolling based on JIS Z2241 to measure 0.2% proof stress (YS: MPa), and 0.2% of them. The difference in proof stress was calculated.
<R value>
For each test piece, the tensile test in each direction is carried out in order to calculate the Langford value in the rolling direction (r0), the Langford value at 45 ° from the rolling direction (r45), and the Langford value in the sheet width direction (r90) went. Let the plate width and plate thickness before tensile deformation be W ₀ and T ₀ , and the plate width and plate thickness when 5% tensile deformation be applied be W and T, respectively, r = ln (W ₀ / W) / The Rankford value in each tensile direction was calculated by (T ₀ / T).
The average r value of each direction was calculated by r = (r0 + 2 × r45 + r90) / 4.
<Conductivity>
The conductivity (EC;% IACS) was determined by volume resistivity measurement using a double bridge in accordance with JIS H0505.

<Average grain size>
The average crystal grain size was determined by a cutting method (JIS H0501) by subjecting a cross section parallel to the rolling direction to mirror polishing and then chemically corroding.

<Crystal orientation>
For each test piece, using a RINT 2500 X-ray diffractometer manufactured by Rigaku Corporation, the diffraction intensity curve of the surface is obtained under the following measurement conditions, {200} crystal face, {220} crystal face, {311} crystal The integrated intensity I of each of the faces was measured to calculate (I {220} + I {311}) / I {200}. In addition, with respect to a pure copper powder standard sample, the integrated intensity I of {200} crystal plane was measured under the same measurement conditions to calculate I {200} / I ₀ {200}.
・ Target: Co tube ・ Tube voltage: 30kV
・ Tube current: 100mA
・ Scanning speed: 5 ° / min
・ Sampling width: 0.02 °
・ Measurement range (2θ): 5 ° to 150 °

<Pressability>
The punch was displaced toward the die at a speed of 0.1 mm / s and pressed while being disposed between a square punch (punch) of 10 mm side and a die provided with a clearance of 0.01 mm. When observing the press fracture surface after pressing by an optical microscope, as Figure 1, that the width of the observation plane and L _0, the total length of the boundary portion of the shear surface and the fracture surface is L, pressed at L / L ₀ The sex was evaluated. The total length L was calculated from the photograph of the observation surface using image analysis software. The width L _{0 of the} observation surface is usually 5 mm or more, and the observation surface is at the center in the width direction of the press fracture surface. It was evaluated that the case of L / L ₀ > 1.3 was inferior to pressability.

<Drawability>
Using a tester manufactured by Eriksen, a cup was produced under the conditions of blank diameter: φ64 mm, punch (punch) diameter: φ33 mm, sheet pressure: 3.0 kN, lubricant: grease.
The cup is placed on the glass plate with the open end down, and the gap between the recess between the ears and the glass plate is measured with a reading microscope, and the gap between the four ears generated in the cup The average value of was calculated, and it was set as the height of the ear.
Further, the appearance of the cup was visually observed to determine the presence or absence of rough skin.
The drawability was evaluated according to the following criteria.
○: The height of the ear is 0.5 mm or less, without rough skin ×: The height of the ear exceeds 0.5 mm, and the skin roughened

  As shown in Tables 1 and 2, all of Inventive Examples 1 to 20 were subjected to the first solution treatment, the second cold rolling, the second solution treatment, and the aging treatment under predetermined conditions. 0.2% proof stress in the direction is 630 MPa or more, conductivity is 50% IACS or more, and the average grain size in the rolling parallel section is 10 to 20 μm, and further, (I {220} + I {311}) / I {200 } It became ≧ 5.0. As a result, good pressability and drawability could be obtained.

In Comparative Examples 1 to 3, the crystal grains are coarsened or the crystal orientation is changed due to the fact that the first solution treatment was not performed, or the temperature of the first solution treatment was too high or too low. The pressability was deteriorated without satisfying the predetermined conditions.
In Comparative Example 4, when the degree of working of the second cold rolling was too high, the crystal grain size became smaller than the predetermined range, and the drawability deteriorated.
In Comparative Example 5, when the degree of working of the second cold rolling was too low, the crystal grains were coarsened and the pressability was deteriorated.
In Comparative Example 6, since the surface roughness Ra after the second cold rolling was small, the crystal orientation did not satisfy the predetermined condition, and the pressability deteriorated.
In Comparative Example 7, the 0.2% proof stress decreased due to the temperature of the second solution treatment being too low. In addition, the crystal grain size became smaller than the predetermined range, and the drawability deteriorated.
In Comparative Example 8, when the temperature of the second solution treatment was too high, the crystal grains became coarse and the pressability deteriorated.
In Comparative Example 9, the conductivity was low due to the temperature of the aging treatment being too low.
In Comparative Example 10, the 0.2% proof stress was lowered due to the temperature of the aging treatment being too high.

In Comparative Example 11, the amount of Ni was smaller than the predetermined range, and the Ni / Co fell below the predetermined range, thereby deteriorating the drawability.
In Comparative Example 12, the conductivity decreased because the amount of Ni was larger than the predetermined range and Ni / Co exceeded the predetermined range.
In Comparative Example 13, the conductivity decreased due to the fact that (Ni + Co) / Si deviated from the predetermined range by mass ratio.
In Comparative Example 14, cracking occurred during hot working because the amount of Co was larger than the predetermined range.

  From the above, it has been found that according to the present invention, the dimensional stability when pressed into a connector shape or the like can be improved while having a 0.2% proof stress and conductivity suitable for an electronic material.

Claims (7)

It contains 0.5 to 3.0% by mass of Co, 0.1 to 2.0% by mass of Ni, and 0.1 to 1.5% by mass of Si, and the mass ratio of (Ni + Co) / Si is 3. % . 0 to 5.0 , the balance being copper and unavoidable impurities, the 0.2% proof stress in the rolling parallel direction is 630 MPa or more, the conductivity is 50% IACS or more, and the average grain size in the rolling parallel cross section is 10 to 10 20 μm (but excluding 10 μm) , X-ray diffraction integral intensity I {200} from {200} crystal plane at the surface, and X-ray diffraction integral intensity I {220} from {220} crystal plane The copper alloy for electronic materials which the X-ray diffraction integral intensity I {311} from a {311} crystal plane fulfills the relation of (I {220} + I {311}) / I {200} 5.0 5.0.   The copper alloy for electronic materials according to claim 1, wherein a mass ratio of Ni to Co (Ni / Co) is 0.1 to 2.0. A parallel to the rolling plane from the 0.2% proof stress in the rolling parallel direction, the difference between the 0.2% proof stress obtained by subtracting the 0.2% proof stress of a direction perpendicular to the rolling direction parallel claim 1 or less 50MPa Or the copper alloy for electronic materials as described in 2. And {200} X-ray diffraction integrated intensity I {200} from the crystal plane at the surface, a standard pure copper powder X-ray diffraction析積partial intensity I ₀ {200} _{but, I {200} / I 0} {200} ≦ 1 The copper alloy for electronic materials according to any one of claims 1 to 3, which satisfies the relationship of .0.   The rankford value r is 1.0 or more (where r0 is the rankford value in the rolling direction, r45 is the rankford value 45 ° from the rolling direction, and r90 is the rankford value in the sheet width direction r = r0 + 2 × The copper alloy for electronic materials according to any one of claims 1 to 4, which is r45 + r90) / 4).   Furthermore, the copper alloy for electronic materials as described in any one of Claims 1-5 which contains Cr by 0.5 mass% or less.   Furthermore, each contains at most 1.0 mass% of Zn and Sn and at most 0.2 mass% or less of Mg, P, Ca and Mn, respectively, and is selected from those Zn, Sn, Mg, P, Ca and Mn The copper alloy for electronic materials according to any one of claims 1 to 6, wherein a total of at least one or more kinds is 2.0 mass% or less.