JP6246454B2 - Cu-Ni-Si alloy and method for producing the same - Google Patents

Description

  The present invention relates to a Cu—Ni—Si alloy having excellent bending workability and stress relaxation characteristics suitable as a conductive spring material for connectors, terminals, relays, switches and the like.

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.
Furthermore, the material is required to have good bending workability. Good bending workability is required not only to cause no cracking in the bent portion when the material is press-molded into a terminal or the like, but also to reduce wrinkles generated on the bent surface. This is because, when the surface of the press product is inspected, if the bending wrinkle is large, an NG determination is made and the product yield is greatly reduced.
Further, for example, in-vehicle terminals used in an engine room are not only generated by energization, but are heated depending on the usage environment, and therefore, a material is required to have good stress relaxation characteristics. This is because if the stress relaxation characteristic is poor, the spring portion of the terminal will sag and contact failure will occur.

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 the Corson alloys, Cu—Ni—Si based alloys are alloy systems having both high strength and relatively high electrical conductivity, and the strengthening mechanism is that Ni—Si based intermetallic compound particles are precipitated in the Cu matrix. Thus, the strength and conductivity are improved.
And as above-mentioned, the favorable bending workability and stress relaxation characteristic are desired also for Cu-Ni-Si type alloy.

  As a method for improving the bending workability and / or stress relaxation characteristics of a Cu—Ni—Si based 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> is set to 50% or more. In Patent Document 2, the area ratio of {001} <100> is set to 50% or more, and there is no layered boundary. Bending workability is improved. In Patent Document 3, when the area ratio of {001} <100> on the surface of the material is W0 and the area ratio of {001} <100> at a position 1/4 with respect to the depth direction of the material is W4, W0 / Bendability and stress relaxation characteristics are improved by setting W4 to 0.8 to 1.5, W0 to 5 to 48%, and crystal grain size to 12 to 100 μm.

JP 2006-283059 A JP 2006-152392 A WO2011 / 068121

However, although Patent Documents 1 and 2 provide good bending workability, the crystal grain size is as fine as 10 μm or less, so the stress relaxation characteristics are poor. On the other hand, in Patent Document 3, although good stress relaxation characteristics can be obtained, since the crystal grain size is as coarse as 12 to 100 μm, wrinkles generated on the surface of the material after bending are large, and materials used for connectors and the like It cannot be said that it has good bending workability.
Accordingly, an object of the present invention is to improve bending workability and stress relaxation characteristics of a Cu—Ni—Si based alloy.

Slip deformation occurs on the surface of the material that has undergone bending deformation, so that a depression is formed on the material surface, which is observed as bending wrinkles. Since the slip deformation preferentially occurs at the crystal grain boundary, if the crystal grain is coarse, a local depression occurs and the bending wrinkle becomes large. Therefore, in order to reduce bending wrinkles, the crystal grains may be refined.
On the other hand, when a material subjected to external force is heated, the material is deformed. This is thought to be due to the movement of dislocations introduced by external force, and the higher the dislocation density, the easier it is to deform. If the crystal grains of the material are fine, the dislocation density increases and the stress relaxation characteristics deteriorate. Therefore, in order to obtain good stress relaxation characteristics, the crystal grains may be coarsened.
As a result of intensive studies, the present inventor has found that a combination of fine crystal grains and coarse crystal grains has both good bending workability and stress relaxation characteristics.

  In one aspect, the present invention completed on the basis of the above findings contains 1.0 to 4.5 mass% Ni and 0.2 to 1.0 mass% Si, with the balance being copper and inevitable impurities. Bending in which the ratio of the number of crystal grains having a crystal grain size of 10 μm or less is 15% or more and the ratio of the number of crystal grains having a diameter of 20 μm or more is 15% or more with respect to the number of crystal grains per unit area in a rolled parallel section It is a Cu—Ni—Si based alloy excellent in workability and stress relaxation characteristics.

  In one embodiment, the Cu—Ni—Si alloy according to the present invention has a total amount of at least one of Sn, Zn, Mg, Fe, Ti, Zr, Al, P, Mn, Co, Cr, and Ag. 005 to 2.5% by mass.

In another aspect of the present invention, 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 inevitable impurities is produced. The ingot is hot-rolled at a temperature of 800 to 1000 ° C. to a thickness of about 5 to 20 mm, then cold-rolled with a workability of 30 to 99%, and a heat treatment (pre-annealing) with a softening degree of 0.25 to 0.75. ) , Followed by cold rolling at a workability of 7 to 50% and a strain rate of 2 × 10 ⁻⁴ (1 / second) or less, and then a solution treatment at 700 to 900 ° C. for 5 to 300 seconds. and then, an aging treatment, a method of performing cold rolling and strain relief annealing in this order this method of manufacturing a Cu-Ni-Si alloy of the present invention the softening degree represented by the following equation when expressed as S Is:
S = (σ ₀ −σ) / (σ ₀ −σ ₉₀₀ )
(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).

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

  In still another aspect of the present invention, a copper product having the copper alloy is provided.

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

  It is possible to provide a Cu—Ni—Si based alloy having bending workability and stress relaxation characteristics suitable as conductive spring materials for connectors, terminals, relays, switches and the like, and a method for producing the same.

It is a graph which shows the relationship between the annealing temperature when the alloy which concerns on this invention is annealed at various temperatures, and tensile strength. It is explanatory drawing of the stress relaxation test in an Example. It is explanatory drawing of the stress relaxation test in an Example.

(1) Ni and Si concentrations Ni and Si are precipitated as intermetallic compounds such as Ni ₂ Si by performing an 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 (hereinafter referred to as “%”) or the Si concentration is less than 0.2%, the desired strength cannot be obtained, and conversely, when the Ni concentration exceeds 4.5%, or If the Si concentration exceeds 1.0%, the hot workability deteriorates. For this reason, in the Cu-Ni-Si based alloy according to the present invention, the addition amount of Ni is set to 1.0 to 4.5%, and the addition amount of Si is set to 0.2 to 1.0%. Furthermore, the addition amount of Ni is preferably 1.2 to 4.0%, and the addition amount of Si is preferably 0.25 to 0.9%.

(2) Other additive elements Addition of Sn, Zn, Mg, Fe, Ti, Zr, 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, Al, P, Mn, Co, Cr and Ag is less than 0.005%, the above effect cannot be obtained. If it exceeds 1, the electrical conductivity will be significantly lowered and it will not be possible to use it as an electrical / electronic component material. For this reason, in the Cu-Ni-Si based alloy according to the present invention, these elements are preferably contained in a total amount of 0.005 to 2.5%, more preferably 0.1 to 2.0%. .

(3) Crystal grains The ratio of the number of crystal grains having a crystal grain size of 10 μm or less to the number of crystal grains per unit area in a cross section (rolling parallel cross section) along the rolling parallel direction of the copper alloy is 15% or more and 20 μm or more. When the ratio of the number of crystal grains is 15% or more, good bending workability and stress relaxation characteristics can be obtained. Preferably, the ratio of the number of any crystal grains is 20% or more. If the ratio of the number of crystal grains having a crystal grain size of 10 μm or less is less than 15%, bending wrinkles after bending will increase, and if the ratio of the number of crystal grains having a grain size of 20 μm or more is less than 15%, the stress relaxation characteristics will deteriorate. . Preferably, the ratio of the number of crystal grains having a crystal grain size of 10 μm or less is 18% or more, and the ratio of the number of crystal grains having a crystal grain size of 20 μm or more is 18% or more.

(4) Manufacturing method As a manufacturing method of this invention, first, raw materials, such as electrolytic copper, Ni, Si, are melt | dissolved in a melting furnace, and the molten metal of a desired composition is obtained. Then, this molten metal is cast into an ingot. Thereafter, strips having desired thickness and characteristics in the order of hot rolling, first cold rolling, heat treatment (pre-annealing) , second cold rolling, solution treatment, aging treatment, and third cold rolling. And finish in foil. After heat treatment (pre-annealing) , 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, it performed in order to obtain the crystal grains, prior to solution treatment, heat treatment (hereinafter, unified to the preliminary annealing.) And a relatively low degree of processing and the second cold rolling of low distortion rate. 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 based 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 what. Recrystallization progresses when the sample arrival temperature is 500 to 700 ° C., and the tensile strength rapidly decreases. 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 outside the range of 0.25 to 0.75, the ratio of the number of crystal grains of 10 μm or less is less than 15% and / or the ratio of the number of crystal grains of 20 μm or less is less than 15%.
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, second cold rolling is performed with a workability R of 7 to 50%. Degree of processing R (%)
R = (t ₀ −t) / t ₀ × 100
(T ₀ : thickness before rolling, t: thickness after rolling)
Define in.
When the workability R is out of this range, the ratio of the number of crystal grains of 10 μm or less is less than 15% and / or the ratio of the number of crystal grains of 20 μm or less is less than 15%.
Furthermore, in order to control the ratio of the number of crystal grains of 10 μm or less to 15% or more, the strain rate of the second cold rolling is controlled to 2 × 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 viewpoint of the crystal grain size, but rolling that is less than 1 × 10 ⁻⁵ (1 / second) is not industrially preferable because the rolling time is long. The strain rate of rolling in a general industry is 4 × 10 ⁻⁴ (1 / second) or more.
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 (degree of softening S = 0.25 to 0.75)
(5) Cold rolling (working degree 7 to 50%, strain rate 2 × 10 ⁻⁴ (1 / second) or less)
(6) Solution treatment (700 to 900 ° C. for 5 to 300 seconds)
(7) Cold rolling (working degree 1-60%)
(8) Aging treatment (2 to 20 hours at 350 to 550 ° C.)
(9) Cold rolling (working degree 1-50%)
(10) Strain relief annealing (at 300 to 700 ° C. for 5 seconds to 10 hours)
Here, it is preferable that the workability of cold rolling (3) is 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 optionally performed to increase the strength, and the strength increases as the degree of rolling process increases, 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.
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.
In addition, what is necessary is just to select the general manufacturing conditions of a Cu-Ni-Si type alloy about process (2), (6), and (8).
The Cu—Ni—Si based alloy according to the present invention can be processed into various copper products, for example, plates and strips. Further, the Cu—Ni—Si based alloy according to the present invention includes a lead frame, a connector, and a pin. It can be used for electronic equipment parts such as terminals, relays and switches.
Moreover, the final plate thickness (product plate thickness) of the Cu—Ni—Si based 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 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
Cu-2.7 mass% Ni-0.58 mass% Si-0.5 mass% Sn-0.4 mass% Zn alloy was used as an experimental material, pre-annealing, light rolling workability and strain rate, and each crystal grain The relationship between the ratio of the number of grains and the influence of the ratio of the number of each crystal grain on the bendability and stress relaxation characteristics of the product were examined.
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, and 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 the sample into an electric furnace adjusted to a predetermined temperature, hold it for a predetermined time, then place the sample in a water bath and cool (water cooling) or leave the sample in the atmosphere and cool (air cooling) Cooled under conditions.
(3) Second cold rolling: Cold rolling was performed to a thickness of 0.18 mm at various rolling degrees and strain rates.
(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 a workability of 17% from 0.18 mm to 0.15 mm.
(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 pre-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 according to JIS Z 2241 using a tensile tester, and the respective values were set as σ ₀ and σ _T. 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 950 ° C. furnace), and the tensile strength was measured in parallel with the rolling direction to obtain σ ₉₀₀ . . The softening degree S _T was determined from σ ₀ , σ _T , and σ ₉₀₀ .
S _T = (σ ₀ −σ _T ) / (σ ₀ −σ ₉₀₀ )

(Measurement of crystal grain number and crystal grain size of product)
The structure of the cross section parallel to the rolling direction is revealed by etching (water-NH ₃ (40 vol%)-H ₂ O ₂ (0.6 vol%)), and an image analysis apparatus attached to a digital microscope manufactured by Keyence Corporation is used. Then, the number of crystal grains contained in 20000 μm ² and the area of each crystal grain were measured. Each crystal grain was regarded as a perfect circle, the diameter was calculated from the area, and this was used as the crystal grain diameter. However, crystal grains not completely contained within 20000 μm ² were excluded from the measurement.

(Product tensile test)
A tensile test was performed in parallel with the rolling direction in accordance with JIS Z 2241 using a tensile tester to obtain a stress-strain curve. From this curve, tensile strength and 0.2% yield strength were determined.

(Product bending test)
After performing the W bending test (bending radius 0.075 mm) described in JIS H 3130 in a direction parallel to the rolling direction, the bending surface was observed and described in JBMA T307, which is a standard of the Japan Copper and Brass Association. Bending workability was evaluated according to the evaluation criteria. The evaluation criteria are A for no wrinkles, B for small wrinkles, C for large wrinkles, D for small cracks, and E for large cracks.

(Product stress relaxation test)
A strip-shaped test piece having a width of 10 mm and a length of 100 mm was collected so that the longitudinal direction of the test piece was parallel to the rolling direction. As shown in FIG. 2, with the position of l = 25 mm as the working point, the test piece was given a deflection of y ₀ and a stress (σ ₀ ) corresponding to 80% of the 0.2% proof stress was applied. y ₀ is determined from the following equation.
y ₀ = (2/3) · l ² · σ ₀ / (E · T)
Here, E is Young's modulus and T is the thickness of the sample. After unloading after heating at 150 ° C. for 1000 hours, the amount of permanent deformation (height) y was measured as shown in FIG. 3, and the stress relaxation rate (%) was calculated from y / y ₀ × 100.
Table 1 shows test conditions and evaluation results.

Inventive examples were manufactured under the conditions specified by the present invention, the ratio of the number of crystal grains of each crystal grain size satisfied the present invention, the evaluation of bendability was B or more, and the stress relaxation rate was 20% or less. Good bending workability and stress relaxation characteristics were obtained.
In Comparative Example 1, since the degree of softening in the preliminary annealing was less than 0.25, the ratio of the number of crystal grains of 20 μm or more was less than 15%, and the stress relaxation characteristics were poor. In Comparative Example 2, since the degree of softening in the pre-annealing exceeded 0.75, the ratio of the number of crystal grains of 10 μm or less and the ratio of the number of crystal grains of 20 μm or more were less than 15%, and bending workability and stress relaxation characteristics were improved. It was bad. In Comparative Example 3, the degree of workability of the second rolling was less than 7%, so that the ratio of the number of crystal grains of 10 μm or less and the ratio of the number of crystal grains of 20 μm or more were less than 15%, and the bending workability and stress relaxation characteristics were improved. It was bad. In Comparative Example 4, since the workability of the second rolling exceeded 50%, the ratio of the number of crystal grains of 20 μm or more was less than 15%, and the stress relaxation characteristics were poor. In Comparative Example 5, the strain rate of the second rolling deviated from the definition of the present invention, and the ratio of the number of crystal grains of 10 μm or less was less than 15%, and the bending workability was poor.
Note that Comparative Example 5 was performed within the range of conditions recommended by Patent Document 3.

(Example 2)
The result which verified that the improvement effect of the bendability and the stress relaxation characteristic shown in Example 1 was obtained also with the Cu-Ni-Si alloy of a different component and manufacturing conditions is shown.
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. This plate was subjected to rolling and heat treatment in the following process order to obtain a product sample having a plate thickness shown in Table 2.
(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, hold it for a predetermined time, and then place the sample in a water bath for cooling (water cooling) or leaving the sample in the atmosphere for cooling (air cooling) It cooled in the conditions of.
(3) Second cold rolling: Cold rolling was performed to a thickness of 0.18 mm at various rolling degrees and strain rates.
(4) Solution treatment: The sample was inserted into an electric furnace adjusted to various temperatures and held for 10 seconds, and then the sample was placed in a water bath and cooled.
(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 rolled from 0.18 mm to 0.15 mm at a workability 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 preliminary annealing, and a product sample.
Tables 2 and 3 show test conditions and evaluation results. When the strain relief annealing is not performed, “none” is written in the temperature column.

Inventive examples were manufactured under the conditions specified by the present invention, the ratio of the number of crystal grains of each crystal grain size satisfied the present invention, the evaluation of bendability was B or more, and the stress relaxation rate was 20% or less. Good bending workability and stress relaxation characteristics were obtained.
On the other hand, in Comparative Examples 6 and 7, the degree of softening in the pre-annealing was out of the definition of the present invention. Therefore, in Comparative Example 6, the ratio of the number of crystal grains of 20 μm or more was less than 15% and the stress relaxation characteristics were poor. Ratio of Comparative Example 7 ratio and 20μm or more crystal grains number in the following grain number 10μm is less than 15%, resulting in poor stress relaxation properties. In Comparative Examples 8 and 9 that the working ratio of the second rolling off the provision of the present invention, the ratio of the rate and 20μm or more crystal grains number of both 10μm following grain number is less than 15%, stress relaxation characteristics Was bad. In Comparative Example 10, the strain rate of the second rolling deviated from the definition of the present invention, so the ratio of the number of crystal grains of 10 μm or less was less than 15%, and the bending workability was poor. In Comparative Example 11, the Ni and Si concentrations were lower than those of the present invention, and the bending workability and stress relaxation characteristics were good, but the 0.2% proof stress did not reach 500 MPa.

Claims (6)

  1.0-4.5 mass% Ni and 0.2-1.0 mass% Si are contained, the remainder consists of copper and unavoidable impurities, and with respect to the number of crystal grains per unit area in the rolled parallel section Cu-Ni-Si-based alloy having excellent bending workability and stress relaxation characteristics, wherein the ratio of the number of crystal grains having a grain size of 10 μm or less is 15% or more, and the ratio of the number of crystal grains having a grain size of 20 μm or more is 15% or more .   The Cu- of Claim 1 which contains 0.005-2.5 mass% of 1 or more types in total among Sn, Zn, Mg, Fe, Ti, Zr, Al, P, Mn, Co, Cr, and Ag. 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, with the balance being made of copper and inevitable impurities is prepared. The ingot is heated at a temperature of 800 to 1000 ° C. After hot-rolling to a thickness of about 5 to 20 mm, cold-rolling with a working degree of 30 to 99%, pre-annealing with a softening degree of 0.25 to 0.75, and then a working degree of 7 to 50% and strain After performing cold rolling at a speed of 2 × 10 ⁻⁴ (1 / second) or less and then performing solution treatment at 700 to 900 ° C. for 5 to 300 seconds, aging treatment , cold rolling and strain relief annealing are performed . is a way to do in the order of this,
The method for producing a Cu-Ni-Si-based alloy according to claim 1 or 2, wherein the softening degree is represented by the following formula when expressed as S:
S = (σ ₀ −σ) / (σ ₀ −σ ₉₀₀ )
(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 said ingot contains 0.005-2.5 mass% in total of 1 or more types in Sn, Zn, Mg, Fe, Ti, Zr, Al, P, Mn, Co, Cr, and Ag. The manufacturing method of the Cu-Ni-Si-type alloy of description.   A copper product comprising the copper alloy according to claim 1.   The electronic device component provided with the copper alloy of Claim 1 or 2.

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