TWI465591B - Cu-Ni-Si alloy and its manufacturing method - Google Patents

Description

Cu-Ni-Si alloy and manufacturing method thereof

The present invention relates to a copper alloy which is suitable as a conductive spring material such as a connector, a terminal, a relay, a switch, etc., and which has excellent strength and bending workability, and a method for producing the same.

In recent years, along with the miniaturization of electronic devices, it has also promoted electrical properties. Miniaturization of electronic components. Further, for copper alloys used for such parts, good strength and electrical conductivity are required.

In the automotive terminal, it is also miniaturized, and requires good strength and electrical conductivity for the copper alloy used. Further, the female terminal for the vehicle is usually subjected to a notch process called a notching process on the curved inner surface before the press bending process. It is processed to improve the shape accuracy after press bending. Along with the miniaturization of the product, there is a tendency for the dent processing to be deepened in order to further improve the shape accuracy of the terminal. Therefore, in addition to good strength and electrical conductivity, a copper alloy for a female terminal for a vehicle is required to have good bending workability. Further, in the relay terminal, the material is tightly bent in order to obtain the required strength, so that the material is required to have good bending workability.

According to these requirements, a precipitation-strengthened copper alloy such as a Carson alloy having high strength and electrical conductivity is used instead of the solid solution-strengthened copper alloy such as phosphor bronze or brass, and the demand thereof is increasing. In the Casson alloy, the Cu-Ni-Si alloy has both high strength and relatively high electrical conductivity, and the strengthening mechanism is strong by precipitating Ni-Si intermetallic compound particles in the Cu substrate. Degree and conductivity increase.

In general, the strength is opposite to the bending workability, and even in the Cu-Ni-Si alloy, the belt maintains high strength while improving bending workability.

As a method of improving the bending workability of the Cu-Ni-Si alloy, there is a method of controlling the crystal orientation by the methods described in Patent Documents 1 to 3. Patent Document 1 improves bending workability by making the area ratio of {001}<100> of the measurement result of EBSD analysis 50% or more; Patent Document 2, {001}<100 by measurement result of EBSP analysis > the area ratio is 50% or more and does not have a layered boundary to improve bending workability; and Patent Document 3, by making the area ratio of {110}<112> of the measurement result of EBSD analysis to 20% or less, The area ratio of {121}<111> is 20% or less, and the area ratio of {001}<100> is 5 to 60% to improve bending workability.

Further, Patent Document 4 improves the bend formability by setting the work hardening index to 0.05 or more.

[Patent Document 1] JP-A-2006-152392 (Patent Document 3) JP-A-2011-0317072 [Patent Document 4] JP-A-2002-266042 Bulletin

The inventors of the present invention conducted a verification test on the effects of the above prior invention. As a result, in the technique of Patent Document 3, when the bending workability was evaluated by W bending having a bending radius of 0.15 mm (bending radius/plate thickness = 1), it was confirmed that there was a certain improvement effect, but When the bending radius is 0.075 mm (bending radius/plate thickness = 0.5) for the W bending test, Cracking occurred and the improvement in bending workability was insufficient. Therefore, an object of the present invention is to provide a Cu-Ni-Si alloy which is suitable as a conductive spring material such as a connector, a terminal, a relay, a switch, or the like, and which has excellent strength and bending workability, and a method for producing the same.

In the prior art, the bending workability of the Cu-Ni-Si alloy was improved by controlling the crystal orientation of the copper alloy, but it was found that excellent results were obtained by controlling not only the crystal orientation but also the work hardening index (n value). Bending workability.

The present invention, which is completed in the context of the above findings, is a Cu-Ni-Si alloy containing 1.0 to 4.5% by mass of Ni and 0.2 to 1.0% by mass of Si, and the remainder is made of copper and not in one aspect. When the EBSD (Electron Back Scatter Diffraction) is measured and the crystal orientation is analyzed, the area ratio of the Cube orientation {001}<100> is 5% or more, and the Brass orientation is {110}. The area ratio of <112> is 20% or less, the area ratio of the Copper orientation {112}<111> is 20% or less, and the work hardening index is 0.2 or less.

In one embodiment, the Cu-Ni-Si alloy of the present invention contains 0.005 to 2.5% by mass of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, and One or more of Ag.

Further, in another aspect of the invention, the method for producing a Cu-Ni-Si alloy according to the invention is characterized in that it contains 1.0 to 4.5% by mass of Ni and 0.2 to 1.0% by mass of Si, and the remainder is made of copper. And an ingot composed of unavoidable impurities, after the above-mentioned ingot is subjected to hot rolling, cold rolling, heat treatment of softening degree of 0.25 to 0.75, and then cold rolling of a processing degree of 7 to 50%, and then The solution treatment is carried out, followed by aging treatment in any order and cold rolling at a strain rate of 1 × 10 ^-4 (1/s) or less.

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

In still another aspect, the present invention is a copper-extended product comprising the above copper alloy.

In still another aspect, the invention is an electronic machine part comprising the above copper alloy.

According to the present invention, it is possible to provide a Cu-Ni-Si alloy which is suitable as a conductive spring material such as a connector, a terminal, a relay, a switch, or the like, and which has excellent strength and bending workability, and a method for producing the same.

(Ni and Si concentration)

Ni and Si are precipitated as an intermetallic compound such as Ni ₂ Si by aging treatment. This compound can increase the strength and reduce Ni and Si which are dissolved in the matrix of the Cu by precipitation, and thus the conductivity is improved. However, if 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. On the other hand, if the Ni concentration exceeds 4.5% by mass or the Si concentration exceeds 1.0% by mass, the hot workability deteriorates. Therefore, in the Cu-Ni-Si alloy of the present invention, the Ni concentration is controlled to 1.0 to 4.5% by mass, and the Si concentration is controlled to 0.2 to 1.0% by mass. The Ni concentration is preferably from 1.3 to 4.0% by mass, and the Si concentration is preferably from 0.3 to 0.9% by mass.

(other added elements)

The addition of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, and Ag contributes to an increase in strength. Further, Zn has an effect of improving the heat-resistant peeling property of Sn plating, Mg has an effect of improving stress relaxation characteristics, and Zr, Cr, and Mn have an effect of improving hot workability. If the concentration of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, and Ag is less than 0.005 mass% in total, the above effect cannot be obtained, and if it exceeds 2.5% by mass, The conductivity is significantly reduced and cannot be used as electrical. Electronic parts materials. Therefore, the Cu-Ni-Si alloy of the present invention preferably contains the elements in an amount of 0.005 to 2.5% by mass based on the total amount, more preferably 0.1 to 2.0% by mass.

(crystal orientation)

When the copper alloy has a large orientation and the Brass orientation and the Copper orientation are small, the uneven deformation can be suppressed and the bendability is improved. Here, the Cube orientation refers to a state in which the (001) plane faces the normal direction (ND) of the rolling surface, and the (100) plane faces the rolling direction (RD), and is expressed by an index of {001}<100>. The Brass orientation refers to a state in which the (110) plane faces ND and the (112) plane faces RD, and is expressed by an index of {110}<112>. The "Copper orientation" refers to a state in which the (112) plane faces the ND and the (111) plane faces the RD, and is expressed by an index of {112}<111>.

The Cu-Ni-Si alloy of the present invention controls the area ratio of the Cube orientation to 5% or more. When the area ratio of the Cube orientation becomes less than 5%, the bending workability is rapidly deteriorated. Although the upper limit of the area ratio of the Cube orientation is not limited in terms of flexibility, in the case of the Cu-Ni-Si alloy of the present invention, the area ratio of the Cube orientation is changed regardless of the manufacturing method. Do not Will exceed 80%.

The Cu-Ni-Si alloy of the present invention controls the area ratios of the Copper orientation and the Brass orientation to 20% or less, respectively. If any of the area ratio of the Copper orientation or the area ratio of the Brass orientation exceeds 20%, the bending workability is abruptly deteriorated. Although the lower limit of the area ratio of the Copper orientation and the Brass orientation is not limited in terms of flexibility, in the case of the Cu-Ni-Si alloy of the present invention, the manufacturing method is changed anyway, and the Copper orientation is The area ratio or the area ratio of the Brass orientation is not less than 1%.

(work hardening index)

When the metal is plastically deformed, strain is deposited and work hardening occurs, and the tensile strength of the metal increases. The work hardening index (hereinafter referred to as n value) is used as an index value for the work hardening. The larger the value of n, the greater the increase in tensile strength of the metal caused by work hardening.

In order to form a material into an electronic component such as a connector, it is necessary to perform a press bending process. When the press bending process is performed, the material is work hardened and the tensile strength thereof increases.

Generally, the tensile strength and the bending workability of the material are trade off, and the higher the tensile strength, the worse the bending workability.

Therefore, if the increase in tensile strength due to work hardening due to the press bending process of the material is suppressed, cracking hardly occurs during press bending. In other words, the smaller the value of n, the better the bending workability can be obtained.

The Cu-Ni-Si alloy of the present invention controls the value of n to 0.2 or less. The value of n is preferably 0.1 or less, and more preferably less than 0.05. When the value of n exceeds 0.2, the bending workability is rapidly deteriorated. Although in terms of flexibility, under the value of n The limit value is not limited, but in the case of the Cu-Ni-Si alloy of the present invention, the manufacturing method is changed anyway, and the value of n is not less than 0.01.

(Production method)

As a production method of the present invention, first, a raw material such as electrolytic copper, Ni, or Si is melted in a melting furnace to obtain a desired composition melt. The melt is then cast into an ingot. Thereafter, it is finished into a strip or foil having a desired thickness and characteristics in the order of hot calendering, first cold rolling, heat treatment, second cold calendering, solution treatment, aging treatment, and third cold calendering. After heat treatment, solution treatment and aging treatment, in order to remove the surface oxide film formed during heating, surface pickling or grinding may be performed. The order of aging treatment and third cold rolling can also be replaced. Further, in order to achieve high strength, cold rolling may be performed between the solution treatment and the aging treatment. Further, in order to restore the spring critical value which is lowered by the third cold rolling, the relaxation annealing may be performed after the third cold rolling.

In order to obtain the above crystal orientation, the present invention performs heat treatment (hereinafter referred to as pre-annealing) and second cold rolling with relatively low workability before solution treatment. The pre-annealing is carried out under the conditions of a softening degree S of 0.25 to 0.75.

In Fig. 1, the relationship between the annealing temperature and the tensile strength when the Cu-Ni-Si alloy of the present invention is annealed at various temperatures is exemplified. The sample to which the thermocouple was attached was placed in a furnace heated to a predetermined temperature, and when the temperature of the sample measured by the thermocouple reached a predetermined temperature, the sample was taken out from the furnace and water-cooled, and the tensile strength was measured. Recrystallization is carried out at a sample reaching temperature of 500 to 700 ° C, and the tensile strength is drastically lowered. The gentle decrease in tensile strength on the high temperature side is caused by the growth of recrystallized grains.

The following formula defines the softness S in the pre-annealing.

S=(σ ₀ -σ)/(σ ₀ -σ ₉₀₀ )

Here, the tensile strength before σ ₀ before annealing, σ and σ ₉₀₀ are the tensile strengths after the pre-annealing and after annealing at 900 ° C, respectively. When the Cu-Ni-Si alloy of the present invention is annealed at 900 ° C, it can be stably completely recrystallized. Therefore, a temperature of 900 ° C is used as a reference temperature for knowing the tensile strength after recrystallization.

If S is less than 0.25, the area ratio of the Copper azimuth will increase and exceed 20%. This also causes a decrease in the area ratio of the Cube orientation.

If S exceeds 0.75, the area ratio of the Brass orientation increases and exceeds 20%. This also causes a decrease in the area ratio of the Cube orientation.

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. Usually, when using a continuous annealing furnace, the furnace temperature is 400~700 °C for 5 seconds to 10 minutes; when using the batch annealing furnace, the furnace temperature is 350~600 °C for 30 minutes to 20 hours. Within the scope of this.

Furthermore, the softening degree S of 0.25 to 0.75 can be adjusted by the following procedure.

(1) The tensile test strength (σ ₀ ) was measured for the material before the pre-annealing.

(2) The material before the pre-annealing was annealed at 900 °C. Specifically, the material to which the thermocouple was attached was inserted into a tubular furnace at 950 ° C, and when the temperature of the sample measured by the thermocouple reached 900 ° C, the sample was taken out from the furnace and water-cooled.

(3) The tensile strength (σ ₉₀₀ ) of the material after annealing at 900 ° C was determined.

(4) For example, when σ ₀ is 800 MPa and σ ₉₀₀ is 300 MPa, the tensile strengths corresponding to softening degrees of 0.25 and 0.75 are 675 MPa and 425 MPa, respectively.

(5) The annealing conditions are determined such that the tensile strength after annealing is 425 to 675 MPa.

Further, in the above step (2), "when the temperature of the sample measured by the thermocouple reaches 900 ° C, the sample is taken out of the furnace and water-cooled" is specifically carried out by, for example, first in the furnace. Hanging on a wire, cutting the wire at a time point of reaching 900 ° C and dropping it into a water tank set in the lower part, thereby performing water cooling, or immediately after the sample temperature reaches 900 ° C, The operation was quickly taken out of the furnace and the sample was immersed in a water tank.

After the annealing and before the solution treatment, the second cold rolling is performed in which the working degree R is 7 to 50%. The degree of processing R (%) is defined by the following formula.

R=(t ₀ -t)/t ₀ ×100

(t ₀ : plate thickness before rolling, t: plate thickness after rolling)

If the degree of work R deviates from the range, the area ratio of the Cube orientation may be less than 5%.

Further, in order to control the value of n to 0.2 or less, the strain rate of the third cold rolling is controlled to be 1 × 10 ^-4 (l/s) or less. The so-called strain rate in the present invention is defined as the rolling speed/roll contact arc length, and in order to lower the strain rate, it is effective to lower the rolling speed, increase the number of passes of the rolling, and lengthen the roll contact arc length. In terms of the value of n, the lower limit of the strain rate is not limited, but if the rolling is performed below 1 × 10 ^-5 (l/s), the rolling time becomes long, which is industrially unsatisfactory. . The strain rate in the usual industrial rolling is about 2 × 10 ^-4 to 5 × 10 ^-4 (l/s).

The steps of the method for producing the alloy of the present invention are as follows, as described below.

(1) Casting of ingots (2) Hot rolling (temperature 800~1000 °C, thickness of 5~20 mm) (3) Cold rolling (processing degree 30~99%) (4) Pre-annealing (softening degree S =0.25~0.75)(5) light calendering (processing degree 7~50%) (6) solution treatment (5~300 seconds at 700~900 °C) (7) cold rolling (processing degree 1~60%, Strain rate 1×10 ^-4 (l/s) or less) (8) Aging treatment (2~20 hours at 350~550°C) (9) Cold rolling (processing degree 1~50%, strain rate 1×10 ^{- 4} (l/s) or less) (10) Relaxation annealing (5 seconds to 10 hours at 300~700 °C)

Here, the degree of processing of the cold rolling (3) is preferably set to 30 to 99%. In order to generate recrystallized grains in the pre-annealing (4) portion, it is necessary to introduce strain in advance in cold rolling (3), and an effective strain can be obtained at a working degree of 30% or more. On the other hand, when the degree of work exceeds 99%, cracks may occur at the edges of the rolled material, and the material in the rolling may be broken.

The cold rolling (7) and (9) are arbitrarily performed to achieve high strength and control of the value of n, and the strength increases as the degree of rolling work increases, but the bendability decreases. The effects of the present invention can be obtained regardless of the degree of processing of cold rolling (7) and (9). Among them, cold rolling (7) and (9) When the degree of work exceeds the above upper limit, it is not preferable in terms of flexibility, and the effect that each of the degree of work is lower than the above lower limit is not preferable in terms of the effect of increasing the strength. Further, in order to control the value of n, at least one of cold rolling (7) or cold rolling (9) must be performed.

The relaxation annealing (10) is arbitrarily performed in order to recover the spring critical value or the like which is lowered by the cold rolling in the case of performing the cold rolling (9). The effect of the present invention can be obtained with or without relaxation annealing (10). The relaxation annealing (10) may or may not be performed.

Further, in the steps (2), (6), and (8), the general production conditions of the Cu-Ni-Si-based alloy may be selected.

The Cu-Ni-Si alloy of the present invention can be processed into various copper-stretching products such as plates, strips and foils. Further, the Cu-Ni-Si-based alloy of the present invention can be used for lead frames, connectors, and pins. (pin), electronic components such as terminals, relays, switches, and foils for secondary batteries.

Further, the final thickness (product thickness) of the Cu-Ni-Si alloy of the present invention is not particularly limited, and is usually 0.05 to 1.0 mm in the case of the above-mentioned product use.

[Examples]

In the following, the embodiments of the present invention are shown in conjunction with the comparative examples, but the embodiments are provided to better understand the present invention and its advantages, and are not intended to limit the inventors.

(Example 1)

It will contain 2.6 mass% of Ni, 0.58 mass% of Si, 0.5 mass% of Sn, and 0.4 mass% of Zn, and the remainder is made of copper and inevitable The alloy composed of impurities is used as an experimental material, and the relationship between the processing speed of the pre-annealing, the second cold rolling, and the third cold rolling is related to the crystal orientation and the n value, thereby causing the crystal orientation and the n value to bend the product. The impact of the study.

A high-frequency melting furnace was used to melt 2.5 kg of electrolytic copper in an argon atmosphere using a graphite crucible having an inner diameter of 60 mm and a depth of 200 mm. In order to obtain the alloy composition described above, an alloying element was added, and the temperature of the melt was adjusted to 1300 ° C, and then cast into a mold made of cast iron to produce an ingot having a thickness of 30 mm, a width of 60 mm, and a length of 120 mm. The ingot was heated at 950 ° C for 3 hours and hot rolled until the thickness reached 10 mm. The rust scale on the surface of the hot rolled sheet was removed by grinding with a grinder. The thickness after grinding is 9 mm. Thereafter, rolling and heat treatment were carried out in the following order to prepare a product sample having a thickness of 0.15 mm.

(1) First cold rolling: cold rolling according to the degree of calendering of the second cold rolling until reaching a predetermined thickness.

(2) Pre-annealing: The sample is inserted into an electric furnace adjusted to a predetermined temperature, and after being kept for a predetermined period of time, it is cooled under the following two conditions: the sample is placed in a water tank for cooling (water cooling), or the sample is placed. Cooling in the atmosphere (air cooling).

(3) Second cold rolling: cold rolling in various calendering processes until the thickness reaches 0.18 mm.

(4) Solution treatment: The sample was inserted into an electric furnace adjusted to 800 ° C for 10 seconds, and then the sample was placed in a water tank for cooling.

(5) Aging treatment: heating in an Ar environment at 450 ° C using an electric furnace 5 hours.

(6) Third cold rolling: cold rolling at a strain rate of 17% at various strain rates until the thickness is from 0.18 mm to 0.15 mm.

(7) Relaxation annealing: The sample was inserted into an electric furnace adjusted to 400 ° C, and after holding for 10 seconds, the sample was placed in the atmosphere for cooling.

The sample after the pre-annealing and the sample of the product (in this case, the completion of the relaxation annealing) were evaluated as follows.

(Evaluation of softness before annealing)

For the samples before and after the pre-annealing, the tensile strength parallel to the rolling direction was measured using a tensile tester in accordance with JIS Z 2241, and the respective values were taken as σ ₀ and σ. Further, according to the above procedure (water-cooling when the sample of the furnace at 950 ° C was reached at 900 ° C), an annealed sample at 900 ° C was produced, and the tensile strength parallel to the rolling direction was measured in the same manner to obtain σ ₉₀₀ . The softening degree S is obtained from σ ₀ , σ, and σ ₉₀₀ by the following formula.

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).

For the EBSD measurement, for a sample area of 500 μm square containing more than 200 crystal grains, the step width was 0.5 μm and the orientation was analyzed. Regarding the angle from the ideal azimuth deviation, the rotation angle is calculated as the deviation angle centering on the common rotation axis. For example, (121) [1-11] has a (201017) direction as a rotation axis, and a relationship of 19.4° with respect to the S orientation (231) [6-43], This angle is used as the deviation angle. The shared rotating shaft is represented by a minimum deviation angle. Calculate the deviation angle for all the measurement points and make the first digit of the decimal point a significant number, and divide the area of the crystal grain having the orientation from the Cube orientation, the Copper orientation, and the Brass orientation by 10°, respectively, by the total measurement area, as the area. rate. The information obtained in the azimuth analysis using EBSD includes the orientation information of the depth at which the electron beam penetrates to a depth of 10 nm, but the range is small with respect to the measurement, and is therefore referred to as the area ratio.

( tensile test of the product)

A stress-strain curve was obtained by performing a tensile test in parallel with the rolling direction in accordance with JIS Z 2241 using a tensile tester. Tensile strength and 0.2% endurance were determined from the curve. Further, the stress-strain curve is converted into a true stress-true strain curve, and the n value is read.

(bending test of the product)

When the W bending test described in JIS H 3130 is performed in the parallel direction of the rolling direction, the minimum bending radius (MBR, unit: mm) at which no cracking occurs is determined, and the thickness (t, unit: mm) is measured. Ratio (MBR/t).

The test conditions and evaluation results are shown in Table 1. The invention is based on the conditions specified in the present invention, so that the crystal orientation and the n value satisfy the requirements of the present invention, and good bending workability with an MBR/t of 0.5 or less can be obtained.

In Comparative Example 1, since the softening degree of the pre-annealing was less than 0.25, the area ratio of the Copper orientation exceeded 20%, and the area ratio of the Cube orientation was less than 5%. In Comparative Example 2, since the softening degree of the pre-annealing exceeded 0.75, the area ratio of the Brass orientation exceeded 20%, and the area ratio of the Cube orientation was less than 5%. The degree of processing of the second calendering of Comparative Examples 3 and 4 deviated from the provisions of the present invention, and the Cube orientation was made. The area ratio is less than 5%. The strain rate of the third calendering of Comparative Example 5 deviated from the specification of the present invention, and the value of n was more than 0.2. In the above comparative example, MBR/t was 1, and the bending workability was poor.

Further, Comparative Example 5 is carried out within the conditions recommended by Patent Document 3, and the crystal orientation thereof satisfies the requirements of Patent Document 2.

(Example 2)

Whether the Cu-Ni-Si alloy of different compositions and production conditions can also obtain the bending improvement effect shown in Example 1 was investigated.

Casting, hot rolling, and surface grinding were carried out in the same manner as in Example 1 to obtain a sheet having a thickness of 9 mm having the composition of Table 2. The plate was subjected to rolling and heat treatment in the following order to prepare a product sample having a thickness of 0.15 mm.

(1) First cold rolling: cold rolling is performed according to the degree of calendering of the second cold rolling until the predetermined thickness is reached.

(2) Pre-annealing: Insert the sample into an electric furnace adjusted to a predetermined temperature, and after cooling for a predetermined period of time, perform cooling under the following two conditions: place the sample in a water tank for cooling (water cooling), or place the sample in the sample. Cooling in the atmosphere (air cooling).

(3) Second cold rolling: cold rolling is performed at various calendering degrees until the thickness reaches 0.18 mm.

(4) Solution treatment: The sample was inserted into an electric furnace adjusted to a predetermined temperature, and after holding for 10 seconds, the sample was placed in a water tank for cooling. The temperature is selected within a range in which the average diameter of the recrystallized grains is in the range of 5 to 25 μm.

(5) Aging treatment: using an electric furnace, heating in an Ar environment at a prescribed temperature for 5 hours. This temperature is selected such that the tensile strength after aging is maximized.

(6) Third cold rolling: at various strain rates, cold rolling with a degree of processing of 17% until the thickness is from 0.18 mm to 0.15 mm.

(7) Relaxation annealing: insert the sample into an electric furnace adjusted to a specified temperature. After holding for 10 seconds, the sample was placed in the atmosphere for cooling.

The same evaluation as in Example 1 was carried out on the sample after annealing and the sample of the product. The test conditions and evaluation results are shown in Tables 2 and 3, respectively. When no relaxation annealing is performed, it is marked as "none" in the temperature column.

The alloy of the present invention contains Ni and Si in a predetermined concentration according to the present invention, and the crystal orientation and the n value satisfy the requirements of the present invention by the conditions specified in the present invention, and excellent bending workability with an MBR/t of 0.5 or less can be obtained.

On the other hand, in Comparative Example 6, since the strain rate of the third rolling was deviated from the specification of the present invention, the value of n exceeded 0.2, and the bending workability was poor. In Comparative Examples 7, 8, and 9, since the softening degree under the pre-annealing deviated from the provisions of the present invention, the crystal orientation was deviated from the specification of the present invention, and the bending workability was poor. In Comparative Examples 10 and 11, the degree of processing of the second calendering was deviated from this. According to the invention, the crystal orientation is deviated from the specification of the present invention, and the bending workability is poor. In the case of Comparative Example 12, the concentration of Ni and Si was lower than that of the present invention, and although the bending workability was good, the 0.2% endurance did not even reach 500 MPa.

Fig. 1 is a graph showing the relationship between the annealing temperature and the tensile strength when the Cu-Ni-Si alloy of the present invention is annealed at various temperatures.

Claims (6)

A Cu-Ni-Si alloy containing 1.0 to 4.5% by mass of Ni and 0.2 to 1.0% by mass of Si, and the remainder consisting of copper and unavoidable impurities, and performing EBSD (Electron Back-Scatter Diffraction: When the crystal orientation is measured and analyzed by the electron backscatter diffraction, the area ratio of the Cube orientation {001}<100> is 5% or more, the area ratio of the Brass orientation {110}<112> is 20% or less, and the Copper orientation is {112. The area ratio of } <111> is 20% or less, and the work hardening index is 0.2 or less. For example, the Cu-Ni-Si alloy of the first application of the patent scope contains 0.005 to 2.5% by mass of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co and One or more of Ag. A method for producing a Cu-Ni-Si alloy according to claim 1 or 2, which comprises 1.0 to 4.5% by mass of Ni and 0.2 to 1.0% by mass of Si, and the balance being copper and inevitable An ingot composed of impurities, which is subjected to hot rolling, is subjected to cold rolling, and then subjected to heat treatment of a softening degree of 0.25 to 0.75, and then subjected to cold rolling of a processing degree of 7 to 50%, followed by solution treatment. The aging treatment and the cold rolling at a strain rate of 1 × 10 ^-4 (1/s) or less are performed in an arbitrary order. The method for producing a Cu-Ni-Si alloy according to claim 3, wherein the ingot contains 0.005 to 2.5% by mass of Sn, Zn, Mg, Fe, Ti, Zr, Cr, and One or more of Al, P, Mn, Co, and Ag. A copper-clad product having a copper alloy of claim 1 or 2. An electronic machine part having the patent application scope 1 or 2 Copper alloy.