WO2013031279A1

WO2013031279A1 - Cu-ni-si alloy and method for manufacturing same

Info

Publication number: WO2013031279A1
Application number: PCT/JP2012/059207
Authority: WO
Inventors: 真之長野
Original assignee: Jx日鉱日石金属株式会社
Priority date: 2011-08-29
Filing date: 2012-04-04
Publication date: 2013-03-07
Also published as: JP5117604B1; CN103781925A; TW201309817A; CN107354342A; JP2013047360A; KR101628583B1; TWI465591B; KR20140053376A

Abstract

Provided is a Cu-Ni-Si alloy and a method for manufacturing the Cu-Ni-Si alloy, the Cu-Ni-Si alloy being provided with exceptional strength and bendability, and being suitable as an electro-conductive spring material for a connector, terminal, relay, switch or other component. The Cu-Ni-Si alloy contains 1.0 to 4.5 wt% of Ni, 0.2 to 1.0 wt% of Si, and copper and inevitable impurities constituting the balance. Electron back-scatter diffraction (EBSD) measuring is performed. When the crystal orientation is analyzed the area of cube orientation {001} <100> constitutes 5% or more, the area of brass orientation {110} <112> constitutes 20% or less, and the area of copper orientation {112} <111> constitutes 20% or less. The work-hardening coefficient is 0.2 or less.

Description

Cu-Ni-Si alloy and method for producing the same

The present invention relates to a copper alloy having excellent strength and bending workability, which is suitable as a conductive spring material for connectors, terminals, relays, switches and the like, and a method for producing the same.

In recent years, with the miniaturization of electronic devices, the miniaturization of electrical and electronic components has been progressing. And the copper alloy used for these components is required to have good strength and electrical conductivity.
With the miniaturization of in-vehicle terminals, the copper alloy used is required to have good strength and electrical conductivity. Furthermore, in-vehicle female terminals are often subjected to a notching process called notching on the inner surface of the bending before press bending. This is processing performed to improve the shape accuracy after press bending. With the miniaturization of products, notching processing tends to become deeper in order to further improve the shape accuracy of terminals. Therefore, a copper alloy used for a vehicle-mounted female terminal is required to have good bending workability in addition to good strength and electrical conductivity. Further, as the relay terminal is miniaturized, the material is required to have good bending workability because the material is subjected to tight bending to obtain a desired strength.

In response to these demands, instead of conventional solid solution strengthened copper alloys such as phosphor bronze and brass, precipitation strengthened copper alloys such as a Corson alloy having high strength and electrical conductivity are used, and the demand is increasing. Among Corson alloys, Cu-Ni-Si alloys have both high strength and relatively high electrical conductivity. The strengthening mechanism is based on the precipitation of Ni-Si intermetallic particles in the Cu matrix. In addition, the conductivity is improved.
In general, strength and bending workability are contradictory properties, and it is desired to improve bending workability while maintaining high strength even in Cu—Ni—Si based alloys.

As a method for improving the bending workability of the Cu—Ni—Si alloy, there is a method of controlling the crystal orientation as described in Patent Documents 1 to 3. In Patent Document 1, the area ratio of {001} <100> in the measurement result of EBSD analysis is set to 50% or more. In Patent Document 2, the area ratio of {001} <100> in the measurement result of EBSP analysis is 50%. With the above and no layered boundary, in Patent Document 3, the area ratio of {110} <112> in the measurement result of EBSD analysis is 20% or less, and the area ratio of {121} <111> is 20%. Hereinafter, the bendability is improved by setting the area ratio of {001} <100> to 5 to 60%.
Further, in Patent Document 4, bending workability is improved by setting the work hardening index to 0.05 or more.

JP 2006-283059 A JP 2006-152392 A JP 2011-017072 A JP 2002-266042 A

The present inventors conducted a verification test on the effect of the preceding invention. As a result, when the bending workability was evaluated by W bending with a bending radius of 0.15 mm (bending radius / plate thickness = 1) with respect to the technique of Patent Document 3, a certain improvement effect was recognized, but the bending radius was 0. When a W bending test was performed at 0.075 mm (bending radius / plate thickness = 0.5), it was found that cracking occurred and the bending workability was insufficiently improved. Accordingly, the present invention provides a Cu—Ni—Si alloy having excellent strength and bending workability, which is suitable as a conductive spring material for connectors, terminals, relays, switches and the like, and a method for producing the same. And

The conventional technology improves the bending workability of Cu-Ni-Si alloys by controlling the crystal orientation of the copper alloy, but not only controls the crystal orientation but also controls the work hardening index (n value). As a result, it was found that excellent bending workability can be obtained.

The present invention completed on the basis of the above knowledge, in one aspect, contains 1.0 to 4.5 mass% Ni and 0.2 to 1.0 mass% Si, with the balance being copper and inevitable impurities. When the EBSD (Electron Back-Scatter Diffraction: Electron Backscattering Diffraction) measurement is performed and the crystal orientation is analyzed, the area ratio of the Cube orientation {0 0 1} <1 0 0> is 5% or more, and the Brass orientation The area ratio of {1｝ 1 0} <1 1 率 2> is 20% or less, the area ratio of Copper orientation {1 1 2} <1 1 1> is 20% or less, and the work hardening index is 0.2 or less. Cu—Ni—Si alloy.

In one embodiment, the Cu—Ni—Si based alloy according to the present invention includes at least one of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, Cr and Ag in a total amount. 0.005 to 2.5 mass% is contained.

In another aspect of the present invention, an ingot containing 1.0 to 4.5 mass% Ni and 0.2 to 1.0 mass% Si, the balance being copper and inevitable impurities is produced. The ingot is hot-rolled, cold-rolled, heat-treated with a softening degree of 0.25 to 0.75, then cold-rolled with a working degree of 7 to 50%, and then solutionized. This is a method for producing a Cu—Ni—Si based alloy of the present invention, in which after the treatment, aging treatment and cold rolling at a strain rate of 1 × 10 ⁻⁴ (1 / second) or less are performed in an arbitrary order.

In one embodiment of a method for producing a Cu—Ni—Si alloy according to the present invention, the ingot is made of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, Cr, and Ag. One or more of them are contained in a total amount of 0.005 to 2.5% by mass.

In yet another aspect, the present invention is a copper-drawn product provided with the above copper alloy.

In still another aspect, the present invention is an electronic device component including the copper alloy.

According to the present invention, it is possible to provide a Cu—Ni—Si alloy having excellent strength and bending workability, which is suitable as a conductive spring material for connectors, terminals, relays, switches and the like, and a method for producing the same. .

4 is a graph showing the relationship between the annealing temperature and the tensile strength when the Cu—Ni—Si based alloy according to the present invention is annealed at various temperatures.

(Ni and Si concentration)
Ni and Si are precipitated as an intermetallic compound such as Ni ₂ Si by aging treatment. This compound improves the strength, and by precipitation, Ni and Si dissolved in the Cu matrix are reduced, so that the conductivity is improved. However, when the Ni concentration is less than 1.0% by mass or the Si concentration is less than 0.2% by mass, the desired strength cannot be obtained, and conversely, when the Ni concentration exceeds 4.5% by mass or the Si concentration is 1. When it exceeds 0 mass%, hot workability will deteriorate. Therefore, in the Cu—Ni—Si based alloy according to the present invention, the Ni concentration is controlled to 1.0 to 4.5 mass% and the Si concentration is controlled to 0.2 to 1.0 mass%. The Ni concentration is preferably 1.3 to 4.0% by mass, and the Si concentration is preferably 0.3 to 0.9% by mass.

(Other additive elements)
Addition of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, Cr, and Ag contributes to an increase in strength. Furthermore, Zn is effective in improving the heat-resistant peelability of Sn plating, Mg is effective in improving stress relaxation characteristics, and Zr, Cr, and Mn are effective in improving hot workability. If the total concentration of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, Cr and Ag is less than 0.005% by mass, the above effect cannot be obtained. If it exceeds 5% by mass, the electrical conductivity is remarkably lowered and it cannot be used as an electric / electronic component material. Therefore, the Cu—Ni—Si based alloy according to the present invention preferably contains these elements in a total amount of 0.005 to 2.5% by mass, and preferably 0.1 to 2.0% by mass. More preferred.

(Crystal orientation)
In the copper alloy, when the Cube orientation is large and the Brass orientation and the Copper orientation are small, non-uniform deformation is suppressed and bendability is improved. Here, the Cube orientation is a state in which the (0 0 1) plane is oriented in the rolling surface normal direction (ND) and the (1 0 0) plane is oriented in the rolling direction (RD), and {0 0 1} It is indicated by an index of <1 0 0>. The Brass orientation is a state in which the ND faces the (1 1 0) plane and the RD faces the (1 1 2) plane, and is indicated by an index of {1 1 0} <1 1 2>. The Copper orientation is a state in which the ND faces the (1 1 2) plane and the RD faces the (1 1 1) plane, and is represented by an index of {1 1 2} <1 1 1>.
In the Cu—Ni—Si alloy according to the present invention, the area ratio of the Cube orientation is controlled to 5% or more. When the area ratio of the Cube orientation is less than 5%, the bending workability deteriorates rapidly. The upper limit of the area ratio of the Cube orientation is not restricted in terms of bendability, but in the case of the Cu—Ni—Si based alloy according to the present invention, the area ratio of the Cube orientation is not affected by any change in the manufacturing method. Never exceed 80%.
In the Cu—Ni—Si alloy according to the present invention, the area ratios of the Copper orientation and the Brass orientation are each controlled to 20% or less. If either the Copper azimuth area ratio or the Brass azimuth area ratio exceeds 20%, the bending workability deteriorates rapidly. The lower limits of the area ratio of the Copper orientation and the Brass orientation are not restricted in terms of bendability, but in the case of the Cu—Ni—Si based alloy according to the present invention, no matter how the production method is changed, the Copper orientation Either the area ratio or the area ratio of the Brass orientation is never less than 1%.

(Work hardening coefficient)
When a metal is plastically deformed, strain accumulates, work hardening occurs, and the tensile strength of the metal increases. The work hardening coefficient (hereinafter, n value) is a value used as an index of this work hardening. A larger n value indicates that the metal has a greater increase in tensile strength due to work hardening.
In order to mold the material into an electronic component such as a connector, press bending must be performed. When press bending is performed, the material is work-hardened and its tensile strength increases.
Generally, the tensile strength and bending workability of a material are in a trade-off relationship, and the higher the tensile strength, the worse the bending workability.
Therefore, if the increase in tensile strength due to work hardening caused by press bending of the material is suppressed, cracks are unlikely to occur during press bending. In other words, the smaller the n value, the better the bending workability can be obtained.
In the Cu—Ni—Si alloy according to the present invention, the n value is controlled to 0.2 or less. n value becomes like this. Preferably it is 0.1 or less, More preferably, it is less than 0.05. When the n value exceeds 0.2, the bending workability deteriorates rapidly. The lower limit of the n value is not restricted in terms of bendability, but in the case of the Cu—Ni—Si alloy according to the present invention, the n value is less than 0.01 no matter how the manufacturing method is changed. There is nothing.

(Production method)
In the production method of the present invention, first, raw materials such as electrolytic copper, Ni, and Si are melted in a melting furnace to obtain a molten metal having a desired composition. Then, this molten metal is cast into an ingot. Then, finish into a strip or foil having the desired thickness and characteristics in the order of hot rolling, first cold rolling, heat treatment, second cold rolling, solution treatment, aging treatment, and third cold rolling. . After heat treatment, solution treatment, and aging treatment, pickling or polishing of the surface may be performed in order to remove the surface oxide film generated during heating. The order of the aging treatment and the third cold rolling may be switched. In order to increase the strength, cold rolling may be performed between the solution treatment and aging. Furthermore, strain relief annealing may be performed after the third cold rolling in order to recover the decrease in the spring limit value due to the third cold rolling.
In the present invention, in order to obtain the crystal orientation, heat treatment (hereinafter, pre-annealing) and second cold rolling with a relatively low workability are performed before the solution treatment. The preliminary annealing is performed under the condition that the softening degree S is 0.25 to 0.75.
FIG. 1 illustrates the relationship between the annealing temperature and the tensile strength when the Cu—Ni—Si alloy according to the present invention is annealed at various temperatures. A sample with a thermocouple attached is placed in a furnace heated to a specified temperature, and when the sample temperature measured by the thermocouple reaches the specified temperature, the sample is removed from the furnace and cooled with water, and the tensile strength is measured. It is a thing. Recrystallization progresses when the sample arrival temperature is 500 to 700 ° C., and the tensile strength is rapidly reduced. The gradual decrease in tensile strength on the high temperature side is due to the growth of recrystallized grains.
The softening degree S in the pre-annealing is defined by the following equation.
S = (σ ₀ −σ) / (σ ₀ −σ ₉₀₀ )
Here, σ ₀ is the tensile strength before pre-annealing, and σ and σ ₉₀₀ are the tensile strength after pre-annealing and after annealing at 900 ° C., respectively. The temperature of 900 ° C. is adopted as a reference temperature for knowing the tensile strength after recrystallization because the Cu—Ni—Si alloy according to the present invention is stably recrystallized when annealed at 900 ° C. Yes.
When S is less than 0.25, the area ratio of the Copper orientation increases to exceed 20%, and accordingly, the area ratio of the Cube orientation also decreases.
When S exceeds 0.75, the area ratio of the Brass orientation increases and exceeds 20%, and accordingly, the area ratio of the Cube orientation also decreases.
The temperature, time and cooling rate of the pre-annealing are not particularly limited, and it is important to adjust S to the above range. Generally, when a continuous annealing furnace is used, the furnace temperature ranges from 400 to 700 ° C. for 5 seconds to 10 minutes, and when a batch annealing furnace is used, the furnace temperature ranges from 350 to 600 ° C. for 30 minutes to 20 hours. Done in
The softening degree S can be adjusted to 0.25 to 0.75 by the following procedure.
(1) Measure the tensile test strength (σ ₀ ) of the material before pre-annealing.
(2) The material before preliminary annealing is annealed at 900 ° C. Specifically, the material to which the thermocouple is attached is inserted into a tubular furnace at 950 ° C., and when the sample temperature measured by the thermocouple reaches 900 ° C., the sample is taken out of the furnace and cooled with water.
(3) Obtain the tensile strength (σ ₉₀₀ ) of the material after annealing at 900 ° C.
(4) For example, when σ ₀ is 800 MPa and σ ₉₀₀ is 300 MPa, the tensile strengths corresponding to the softening degrees of 0.25 and 0.75 are 675 MPa and 425 MPa, respectively.
(5) The annealing conditions are determined so that the tensile strength after annealing is 425 to 675 MPa.
In the above step (2), “when the sample temperature measured by the thermocouple reaches 900 ° C., the sample is taken out of the furnace and water-cooled” is specifically, for example, the sample is wired in the furnace. When suspended, the wire is cut when it reaches 900 ° C. and dropped into a water tank provided below, or immediately after the sample temperature reaches 900 ° C. by hand from inside the furnace. Take it out quickly by immersing it in a water tank.

After the annealing, prior to the solution treatment, a second cold rolling with a working degree R of 7 to 50% is performed. Degree of processing R (%)
R = (t ₀ −t) / t ₀ × 100
(T ₀ : thickness before rolling, t: thickness after rolling)
Define in.
When the processing degree R is out of this range, the area ratio of the Cube orientation becomes less than 5%.
Further, in order to control the n value to 0.2 or less, the strain rate of the third cold rolling is controlled to 1 × 10 ⁻⁴ (1 / second) or less. The strain rate of the present invention is specified as rolling speed / roll contact arc length, and in order to lower the strain rate, it is effective to slow the rolling speed, increase the number of rolling passes, and lengthen the roll contact arc length. Is. The lower limit of the strain rate is not limited from the point of the n value, but if rolling is performed below 1 × 10 ⁻⁵ (1 / second), the rolling time is long, which is not industrially preferable. The strain rate of rolling in a general industry is about 2 × 10 ⁻⁴ to 5 × 10 ⁻⁴ (1 / second).

It is as follows when the manufacturing method of the alloy which concerns on this invention is listed in process order.
(1) Ingot casting (2) Hot rolling (temperature 800-1000 ° C, thickness 5-20mm)
(3) Cold rolling (working degree 30-99%)
(4) Pre-annealing (softening degree S = 0.25 to 0.75)
(5) Light rolling (working degree 7-50%)
(6) Solution treatment (700 to 900 ° C. for 5 to 300 seconds)
(7) Cold rolling (working degree 1-60%, strain rate 1 × 10 ^-4 (1 / second) or less)
(8) Aging treatment (350 to 550 ° C for 2 to 20 hours)
(9) Cold rolling (working degree 1-50%, strain rate 1 × 10 ^-4 (1 / second) or less)
(10) Strain relief annealing (300 to 700 ° C for 5 seconds to 10 hours)
Here, the working degree of cold rolling (3) is preferably 30 to 99%. In order to generate recrystallized grains partially by pre-annealing (4), it is necessary to introduce strain by cold rolling (3), and effective strain can be obtained at a workability of 30% or more. On the other hand, if the degree of work exceeds 99%, cracks may occur at the edges of the rolled material and the material being rolled may break.
Cold rolling (7) and (9) is arbitrarily performed for increasing the strength and controlling the n value, and the strength increases with an increase in the rolling degree, but the bendability decreases. The effects of the present invention can be obtained regardless of the degree of cold rolling (7) and (9). However, it is not preferable from the viewpoint of bendability that the respective working degrees in the cold rolling (7) and (9) exceed the above upper limit value, and the fact that each working degree is below the above lower limit effect of increasing the strength. From the point of view, it is not preferable. Further, in order to control the n value, it is necessary to perform at least one of cold rolling (7) and cold rolling (9).
The strain relief annealing (10) is optionally performed in order to recover the spring limit value and the like which are lowered by the cold rolling when the cold rolling (9) is performed. The effect of the present invention can be obtained regardless of the presence or absence of strain relief annealing (10). The strain relief annealing (10) may or may not be performed.
For the steps (2), (6) and (8), general production conditions for the Cu—Ni—Si based alloy may be selected.

The Cu—Ni—Si based alloy according to the present invention can be processed into various copper products, such as plates, strips and foils. Furthermore, the Cu—Ni—Si based alloy according to the present invention can be used for lead frames and connectors. It can be used for electronic parts such as pins, terminals, relays, switches, and foil materials for secondary batteries.
Further, the final plate thickness (product plate thickness) of the Cu—Ni—Si alloy according to the present invention is not particularly limited, but is generally 0.05 to 1.0 mm in the case of the above product use.

EXAMPLES Examples of the present invention will be described below together with comparative examples, but these examples are provided for better understanding of the present invention and its advantages, and are not intended to limit the invention.

(Example 1)
An alloy containing Ni: 2.6% by mass, Si: 0.58% by mass, Sn: 0.5% by mass, and Zn: 0.4% by mass with the balance being copper and inevitable impurities is used as an experimental material. , Pre-annealing, workability of the second cold rolling and the relationship between the strain rate of the third cold rolling and the crystal orientation and n value, and the influence of the crystal orientation and n value on the bendability of the product .
In a high-frequency melting furnace, 2.5 kg of electrolytic copper was melted using a graphite crucible having an inner diameter of 60 mm and a depth of 200 mm in an argon atmosphere. Alloy elements were added to obtain the above alloy composition, the melt temperature was adjusted to 1300 ° C., and then cast into a cast iron mold to produce an ingot having a thickness of 30 mm, a width of 60 mm, and a length of 120 mm. This ingot was heated at 950 ° C. for 3 hours and hot-rolled to a thickness of 10 mm. The oxidized scale on the surface of the hot rolled plate was removed by grinding with a grinder. The thickness after grinding was 9 mm. Thereafter, rolling and heat treatment were performed in the following order of steps to produce a product sample having a thickness of 0.15 mm.
(1) First cold rolling: Cold rolling was performed to a predetermined thickness in accordance with the rolling degree of the second cold rolling.
(2) Pre-annealing: Insert a sample into an electric furnace adjusted to a predetermined temperature and hold it for a predetermined time, then place the sample in a water bath for cooling (water cooling), or leave the sample in the atmosphere for cooling (air cooling) 2 Cooled under street conditions.
(3) Second cold rolling: Cold rolling was performed at various rolling degrees to a thickness of 0.18 mm.
(4) Solution treatment: The sample was inserted into an electric furnace adjusted to 800 ° C. and held for 10 seconds, and then the sample was placed in a water bath and cooled.
(5) Aging treatment: Heated in an Ar atmosphere at 450 ° C. for 5 hours using an electric furnace.
(6) Third cold rolling: Cold rolling was performed at various strain rates from 0.18 mm to 0.15 mm at a working degree of 17%.
(7) Strain relief annealing: The sample was inserted into an electric furnace adjusted to 400 ° C. and held for 10 seconds, and then the sample was left in the air and cooled.
The following evaluation was performed on the sample after the preliminary annealing and the product sample (in this case, the strain relief annealing was completed).

(Evaluation of softening degree in preliminary annealing)
About the sample before pre-annealing and after pre-annealing, the tensile strength was measured in parallel with the rolling direction using a tensile tester according to JIS Z 2241, and the respective values were taken as σ ₀ and σ. In addition, a 900 ° C. annealed sample was prepared by the above procedure (water cooling when the sample reached 900 ° C. when inserted in a furnace at 950 ° C.), and the tensile strength was measured in parallel with the rolling direction to obtain σ ₉₀₀ . It was. From σ ₀ , σ, and σ ₉₀₀ , the degree of softening S was determined by the following equation.
S = (σ ₀ −σ) / (σ ₀ −σ ₉₀₀ )

(Measurement of crystal orientation of products)
The area ratios of Cube orientation, Copper orientation, and Brass orientation were measured by EBSD (Electron Back-Scatter Diffraction).
In the EBSD measurement, a sample area of 500 μm square containing 200 or more crystal grains was scanned in 0.5 μm steps, and the orientation was analyzed. Regarding the deviation angle from the ideal orientation, the rotation angle was calculated around the common rotation axis, and was taken as the deviation angle. For example, with respect to the S orientation (2 3 1) [6 -4 3], (1 2 1) [1 -1 1] is rotated by 19.4 ° with the (20 10 17) direction as the rotation axis. This angle was taken as the deviation angle. A common rotation axis that can be expressed at the smallest angle is adopted. The deviation angle is calculated for all measurement points, and the first decimal place is an effective number. The area of crystal grains having an orientation within 10 ° from each of the Cube orientation, Copper orientation, and Brass orientation is the total measurement area. To obtain the area ratio. The information obtained in the azimuth analysis by EBSD includes azimuth information up to a depth of several tens of nanometers in which the electron beam penetrates the sample, but is described as an area ratio because it is sufficiently small with respect to the measured width. .

(Product tensile test)
Using a tensile tester, a tensile test was performed in parallel with the rolling direction in accordance with JIS Z 2241 to obtain a stress-strain curve. Tensile strength and 0.2% yield strength were determined from this curve. Further, the stress-strain curve was converted to a true stress-true strain curve, and the n value was read.

(Product bending test)
When the W bending test described in JIS H 3130 was performed in a direction parallel to the rolling direction, the minimum bending radius (MBR, unit: mm) without cracking was obtained, and the plate thickness (t, unit: mm) and The ratio (MBR / t) was measured.

Table 1 shows test conditions and evaluation results. The inventive examples were produced under the conditions specified by the present invention, the crystal orientation and the n value satisfied the specifications of the present invention, and MBR / t was 0.5 or less and good bending workability was obtained.
In Comparative Example 1, since the degree of softening in the pre-annealing was less than 0.25, the area ratio of Copper orientation exceeded 20%, and the area ratio of Cube orientation was less than 5%. In Comparative Example 2, since the degree of softening in the preliminary annealing exceeded 0.75, the area ratio of the Brass orientation exceeded 20%, and the area ratio of the Cube orientation became less than 5%. In Comparative Examples 3 and 4, the degree of workability of the second rolling deviated from the definition of the present invention, and the area ratio of the Cube orientation was less than 5%. In Comparative Example 5, the strain rate of the third rolling deviated from the definition of the present invention, and the n value exceeded 0.2. In the above comparative examples, MBR / t was 1, and bending workability was poor.
Note that Comparative Example 5 was performed within the range of conditions recommended by Patent Document 3, and the crystal orientation satisfied the provisions of Patent Document 2.

(Example 2)
It was examined whether the bendability improving effect shown in Example 1 could be obtained with Cu—Ni—Si based alloys having different components and production conditions.
Casting, hot rolling and surface grinding were performed in the same manner as in Example 1 to obtain a 9 mm thick plate having the components shown in Table 2. The plate was subjected to rolling and heat treatment in the following process order to produce a product sample having a plate thickness of 0.15 mm.
(1) First cold rolling: Cold rolling was performed to a predetermined thickness in accordance with the rolling degree of the second cold rolling.
(2) Pre-annealing: Insert a sample into an electric furnace adjusted to a predetermined temperature and hold it for a predetermined time, then place the sample in a water bath for cooling (water cooling), or leave the sample in the atmosphere for cooling (air cooling) Cooling was performed under two conditions.
(3) Second cold rolling: Cold rolling was performed at various rolling degrees to a thickness of 0.18 mm.
(4) Solution treatment: The sample was inserted into an electric furnace adjusted to a predetermined temperature and held for 10 seconds, and then the sample was placed in a water bath and cooled. The temperature was selected so that the average diameter of the recrystallized grains was in the range of 5 to 25 μm.
(5) Aging treatment: Heating was performed in an Ar atmosphere using an electric furnace at a predetermined temperature for 5 hours. The temperature was selected to maximize the tensile strength after aging.
(6) Third cold rolling: Cold rolling was performed at various strain rates from 0.18 mm to 0.15 mm at a working degree of 17%.
(7) Strain relief annealing: The sample was inserted into an electric furnace adjusted to a predetermined temperature and held for 10 seconds, and then the sample was left in the air and cooled.

Evaluation similar to Example 1 was performed about the sample after pre-annealing, and a product sample. Tables 2 and 3 show test conditions and evaluation results, respectively. When the strain relief annealing is not performed, “none” is written in the temperature column.
The alloy of the present invention contains Ni and Si at the concentrations specified by the present invention, and is manufactured under the conditions specified by the present invention. The crystal orientation and the n value satisfy the specifications of the present invention, and MBR / t is 0. Bending workability as good as .5 or less was obtained.
On the other hand, in Comparative Example 6, since the strain rate of the third rolling deviated from the definition of the present invention, the n value exceeded 0.2 and the bending workability was poor. In Comparative Examples 7, 8 and 9, the degree of softening in the pre-annealing was out of the definition of the present invention, and in Comparative Examples 10 and 11, the degree of work in the second rolling was out of the definition of the present invention. Beyond the provisions of the invention, the bending workability was poor. In Comparative Example 12, the Ni and Si concentrations were lower than those of the present invention, and the bending workability was good, but the 0.2% proof stress did not reach 500 MPa.

Claims

It contains 1.0 to 4.5 mass% Ni and 0.2 to 1.0 mass% Si, and the balance consists of copper and unavoidable impurities, EBSD (Electron Back-Scatter Diffraction). When measuring and analyzing the crystal orientation, the area ratio of Cube orientation {0 0 1} <1 0 0> is 5% or more, and the area ratio of Brass orientation {1 1 0} <1 1 2> is 20%. Hereinafter, a Cu—Ni—Si alloy having an area ratio of Copper orientation {1 1 2} <1 1 1> of 20% or less and a work hardening index of 0.2 or less.
The content of one or more of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, Cr, and Ag is 0.005 to 2.5 mass% in total. Cu-Ni-Si alloy.
An ingot containing 1.0 to 4.5% by mass of Ni and 0.2 to 1.0% by mass of Si, the balance being made of copper and unavoidable impurities, and hot rolling the ingot, After cold rolling, heat treatment with a softening degree of 0.25 to 0.75, followed by cold rolling with a working degree of 7 to 50%, followed by solution treatment, aging treatment and strain rate The method for producing a Cu-Ni-Si based alloy according to claim 1 or 2, wherein cold rolling of 1 x 10 -4 (1 / second) or less is performed in an arbitrary order.
The ingot contains 0.005 to 2.5 mass% in total of at least one of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, Cr and Ag. 4. A method for producing a Cu—Ni—Si alloy according to 3.
A copper product comprising the copper alloy according to claim 1 or 2.
An electronic device part comprising the copper alloy according to claim 1.