WO2012121109A1 - Cu-Ni-Si BASED ALLOY AND PROCESS FOR MANUFACTURING SAME - Google Patents

Abstract

Provided are: a Cu-Ni-Si based alloy which combines high strength and high notched bend properties; and a process for manufacturing the same. The Cu-Ni-Si based alloy contains 0.8 to 4.5 mass% of Ni and 0.2 to 1.0 mass% of Si with the balance consisting of copper and unavoidable impurities. Further, the Cu-Ni-Si based alloy exhibits an area fraction of Cube orientation {001}<100> of 10 to 80%, an area fraction of Brass orientation {110}<112> of 20% or less, and an area fraction of Copper orientation {112}<111> of 20% or less, when analyzed for crystal orientation in a thicknesswise central part of the sheet by conducting EBSD measurement in parallel to the thickness direction of the sheet, said thicknesswise central part of the sheet being a part that exists at a depth of 45 to 55% of the thickness of the sheet.

Description

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

The present invention has excellent strength, bending workability, stress relaxation suitable as a lead frame material for conductive spring materials such as connectors, terminals, relays and switches, and semiconductor devices such as transistors and integrated circuits (ICs). The present invention relates to a copper alloy having characteristics, conductivity, and the like, and a method for manufacturing the copper alloy.

In recent years, miniaturization of electrical / electronic parts has progressed, and copper alloys used in these parts are required to have good strength, electrical conductivity, and bending workability. In response to this demand, demand for precipitation strengthened copper alloys such as Corson alloys having high strength and conductivity is increasing instead of conventional solid solution strengthened copper alloys such as phosphor bronze and brass. A Cu-Ni-Si alloy, which is one of the Corson alloys, is an alloy in which compound particles of Ni and Si are precipitated in a Cu matrix, and has high strength, high electrical conductivity, and good bending workability. Yes. 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.

In order to improve the dimensional accuracy of the bent portion when pressing a copper alloy plate into an electronic / electronic part such as a connector, the surface of the copper alloy plate is cut in advance, which is called notching, and the copper alloy is cut along the cut. The plate may be bent (hereinafter also referred to as notch bending). This notch bending is frequently used, for example, in press working of a vehicle-mounted female terminal. Since the copper alloy is work-hardened and loses ductility by the notching process, the copper alloy is easily cracked in the subsequent bending process. Therefore, particularly good bending workability is required for the copper alloy used for notch bending.

In recent years, as a technique for improving the bendability of a Cu—Ni—Si based alloy, a method for controlling the area ratio of the Cube orientation {0 0 1} <1 0 0> measured by the SEM-EBSP method has been proposed. . For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2006-283059), (1) casting, (2) hot rolling, (3) cold rolling (working degree of 95% or more), (4) solution treatment, (5 Cube orientation is obtained by sequentially performing steps of cold rolling (working degree 20% or less), (6) aging treatment, (7) cold rolling (working degree 1 to 20%), and (8) short-time annealing. The bendability is improved by controlling the area ratio to 50% or more.

In Patent Document 2 (Japanese Patent Laid-Open No. 2011-17072), the area ratio of the Cube orientation is controlled to 5 to 60%, and at the same time, the area ratios of the Brass orientation and the Copper orientation are both controlled to 20% or less, so that bending workability is improved. Has improved. Manufacturing processes for this purpose include (1) casting, (2) hot rolling, (3) cold rolling (working degree 85 to 99%), (4) heat treatment (300 to 700 ° C, 5 minutes to 20 hours) (5) Cold rolling (working degree 5 to 35%), (6) Solution treatment, (7) Aging treatment, (8) Cold rolling (working degree 2 to 30%), (9) Temper annealing The best bendability is obtained when the steps are sequentially performed.

JP 2006-283059 A JP 2011-17072 A

The present inventors conducted a verification test on the effect of the preceding invention. As a result, with respect to the technique of Patent Document 2, a certain improvement effect was recognized when the bending workability was evaluated by the W bending test. However, sufficient bending workability was not obtained for notch bending. Therefore, an object of the present invention is to provide a Cu—Ni—Si alloy having both high strength and high notch bendability and a method for producing the same.

In the prior art, the crystal orientation of a copper alloy is analyzed by the EBSD method, and the characteristics of the copper alloy are improved based on the obtained data. Here, EBSD (Electron Back Scatter Diffraction: Electron Back Scattering Diffraction) is a reflection electron Kikuchi line diffraction (Kikuchi pattern) generated when a sample is irradiated with an electron beam in a SEM (Scanning Electron Microscope). This is a technique for analyzing crystal orientation by using it. Usually, the surface of the copper alloy is irradiated with an electron beam, and information obtained at this time is orientation information up to a depth of several tens of nanometers in which the electron beam penetrates, that is, orientation information of the polar surface layer.
On the other hand, the present inventors have found that it is necessary to control the crystal orientation inside the copper alloy plate for notch bending. This is because the inner angle of bending moves into the plate by notching. Then, the crystal orientation in the central part in the plate thickness direction was optimized for notch bending, and a manufacturing method for obtaining this crystal orientation was clarified.

In one aspect, the present invention completed on the basis of the above findings contains 0.8 to 4.5 mass% Ni and 0.2 to 1.0 mass% Si, with the balance being copper and inevitable impurities. When the EBSD measurement is performed in parallel with the plate thickness direction at the central portion in the plate thickness direction, which is a cross-sectional position of 45 to 55% of the plate thickness, and the crystal orientation is analyzed, the Cube orientation {0 0 1} The area ratio of <1 0 面積 0> is 10 to 80%, the area ratio of Brass orientation {1 ＜ 1 0} <1 1 2> is 20% or less, and the area ratio of Copper orientation {1 1 2} <1 1 1> It is a Cu—Ni—Si alloy that is 20% or less.

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 3.0% by mass is contained.

In another aspect of the present invention, an ingot containing 0.8 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 at a temperature of 800-1000 ° C. to a thickness of 5-20 mm, then cold-rolled with a working degree of 30-99%, and subjected to a heat treatment with a softening degree of 0.25-0.75. After adjusting the conductivity to the range of 20 to 45% IACS, cold rolling with a workability of 7 to 50% is performed, followed by solution treatment at 700 to 900 ° C. for 5 to 300 seconds, and 350 to 550 ° C. In this method, the aging treatment is performed for 2 to 20 hours.
The softening degree, the softening degree at the temperature T as S _T, is the method of manufacturing the Cu-Ni-Si-based alloy represented by the following formula:
S _T = (σ ₀ −σ _T ) / (σ ₀ −σ ₉₀₀ )
(Σ ₀ is the tensile strength before annealing, and σ _T and σ ₉₀₀ are the tensile strength after annealing at T ° C. and 900 ° C., respectively).

In one embodiment of the 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 kinds are contained in a total amount of 0.005 to 3.0% 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 both high strength and high notch bendability 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 a figure which shows the test procedure of the notch bending test in an Example.

(Addition amount of Ni and Si)
Ni and Si are deposited as an intermetallic compound such as Ni ₂ Si by performing an appropriate aging treatment. The strength is improved by the action of the precipitates, and Ni and Si dissolved in the Cu matrix are reduced by precipitation, so that the conductivity is improved. However, when Ni is less than 0.8% by mass or Si is less than 0.2% by mass, the desired strength cannot be obtained, and conversely, when Ni exceeds 4.5% by mass or Si is 1.0% by mass When it exceeds, electrical conductivity will fall. For this reason, in the Cu—Ni—Si based alloy according to the present invention, the addition amount of Ni is 0.8 to 4.5 mass% and the addition amount of Si is 0.2 to 1.0 mass%. Further, the addition amount of Ni is preferably 1.0 to 4.0% by mass, and the addition amount of Si is preferably 0.25 to 0.90% by mass.

(Other additive elements)
Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, Cr, and Ag contribute 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 amount 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, and 3.0% by mass. If it exceeds, the electrical conductivity is remarkably lowered. Therefore, the Cu—Ni—Si based alloy according to the present invention preferably contains these elements in a total amount of 0.005 to 3.0 mass%, preferably 0.01 to 2.5 mass%. More preferred.

(Crystal orientation)
When the Cu-Ni-Si-based alloy has many Cube orientations and few Brass orientations and Copper orientations, non-uniform deformation is suppressed and bendability is improved. Here, the Cube orientation is a state in which the (0 0 1) plane faces the rolling surface normal direction (ND) and the (1 0 0) plane faces 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 (1 1 0) plane faces ND and the (1 1 2) plane faces RD, and is indicated by an index of {1 1 0} <1 1 2>. The Copper orientation is a state in which the (1 1 2) plane faces the ND and the (1 1 1) plane faces the RD, and is represented by an index of {1 1 2} <1 1 1>.
When the area ratio of the Cube orientation at the center of the plate thickness is less than 10%, the notch bendability is drastically lowered. On the other hand, when the area ratio of the Cube orientation in the central portion of the plate thickness exceeds 80%, the Young's modulus is rapidly lowered. When the Young's modulus decreases, there is a relationship of P = E × d (P: spring force, E: Young's modulus, d: displacement), so that a desired spring force cannot be obtained after being processed into a component such as a connector. Therefore, the area ratio of the Cube orientation {0 0 1} <1 0 0> is set to 10 to 80%. A more preferable area ratio of the Cube orientation {0 0 1} <1 0 0> is 15 to 60%.
If any of the area ratio of the Copper azimuth and the area ratio of the Brass azimuth in the central portion of the plate thickness exceeds 20%, the notch bendability deteriorates rapidly. For this reason, the area ratio of the Copper azimuth and the area ratio of the Brass azimuth are set to 20% or less. Although the lower limit of the area ratio of Copper orientation in the central portion of the plate thickness and the area ratio of Brass orientation is not restricted from the point of notch bendability, in the case of the alloy of the present invention, no matter how the manufacturing method is changed, Either the area ratio of the Copper azimuth or the area ratio of the Brass azimuth in the central portion of the plate thickness is never less than 1%. The area ratio of the Copper azimuth and the area ratio of the Brass azimuth in the central portion of the plate thickness are preferably 15% or less.
Here, the central portion of the plate thickness refers to a cross-sectional position of 45 to 55% with respect to the plate thickness.

(Production method)
In a general manufacturing process of a Cu—Ni—Si alloy, 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. Thereafter, the strips and foils having desired thickness and characteristics are finished in the order of hot rolling, cold rolling, solution treatment, and aging treatment. After the heat treatment, surface pickling or polishing may be performed in order to remove the surface oxide film generated during aging. In order to increase the strength, cold rolling may be performed between the solution treatment and aging or after aging.
In the present invention, heat treatment (hereinafter also referred to as pre-annealing) and cold rolling (hereinafter also referred to as light rolling) having a relatively low degree of processing are performed before the solution treatment in order to obtain the above crystal orientation.
The preliminary annealing is performed for the purpose of partially generating recrystallized grains in a rolled structure formed by cold rolling after hot rolling. There is an optimum value for the ratio of recrystallized grains in the rolled structure, and the above-mentioned crystal orientation cannot be obtained if the amount is too small or too large. Optimal ratio of recrystallized grains, so that the softening degree S _T defined below is 0.25-0.75 is obtained by adjusting the pre-annealing conditions.
FIG. 1 illustrates the relationship between the annealing temperature and the tensile strength when the alloy according to the present invention is annealed at various temperatures. A sample with a thermocouple attached was inserted into a tube furnace at 950 ° C., and when the sample temperature measured by the thermocouple reached a predetermined temperature, the sample was taken out of the furnace, cooled with water, and the tensile strength was measured. is there. 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 of S _T at the temperature T is defined by the following equation.
S _T = (σ ₀ −σ _T ) / (σ ₀ −σ ₉₀₀ )
Here, σ ₀ is the tensile strength before annealing, and σ _T and σ ₉₀₀ are the tensile strength after annealing at T ° C. and 900 ° C., respectively. The temperature of 900 ° C. is adopted as a reference temperature for knowing the tensile strength after recrystallization because the alloy according to the present invention is stably completely recrystallized when annealed at 900 ° C.
When S _T is less than 0.25, especially at mid-thickness portion, more than 20% increases the area ratio of the Copper orientation is also caused reduction in the area ratio of the Cube orientation accordingly.
When S _T exceeds 0.75, especially at mid-thickness portion, more than 20% increases Brass orientation area ratio of, also caused reduction of the area ratio of the Cube orientation accordingly.
The conductivity after pre-annealing is in the range of 20 to 45% IACS. When the conductivity is less than 20% IACS, the area ratio of the Copper orientation and the Brass orientation is more than 20%, and the Cube orientation area ratio is less than 10%. If the pre-annealing conductivity exceeds 45% IACS, the area ratio of the Cube orientation exceeds 80%.
The temperature, time and cooling rate of the pre-annealing are not particularly limited, and it is important to adjust _ST and conductivity within the above ranges. 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

After the annealing, light rolling with a workability of 7 to 50% is performed prior to the solution treatment. The processing degree R (%) is defined by the following equation.
R = (t ₀ −t) / t ₀ × 100 (t ₀ : plate thickness before rolling, t: plate thickness after rolling)
If the degree of work falls outside this range, the area ratio of the Cube orientation at the center of the plate thickness becomes less than 10%.

It is as follows when the manufacturing method of this invention alloy is listed in order of a process.
(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 _T = 0.25 to 0.75, conductivity = 20 to 45% IACS)
(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%)
(8) Aging treatment (350 to 550 ° C for 2 to 20 hours)
(9) Cold rolling (working degree 1-50%)
(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 optionally performed to increase the strength, and the strength increases as the degree of rolling process increases, but the bendability decreases. The effect of the present invention that the notch bendability is improved by controlling the crystal orientation in the central portion of the plate thickness can be obtained regardless of the presence or absence of cold rolling (7) and (9) and the respective working degrees. Cold rolling (7) and (9) may or may not be performed. 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. Regardless of the presence or absence of strain relief annealing (10), the effect of the present invention is obtained in that the notch bendability is improved by controlling the crystal orientation at the center of the plate thickness. 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 of the present invention can be processed into various copper products such as plates, strips and foils. Furthermore, the Cu—Ni—Si based alloy of the present invention can be used for lead frames, connectors and pins. It can be used for electronic device parts such as terminals, relays, switches, and foil materials for secondary batteries.

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. The relationship between pre-annealing and light rolling conditions and crystal orientation, and the effect of crystal orientation on the bendability and mechanical properties of the product were investigated.
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) Cold rolling: Cold rolling was performed to a predetermined thickness according to the rolling degree of light 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) Light rolling: Cold rolling to various thicknesses of 0.18 mm was performed.
(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) 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 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 )

(Conductivity measurement after pre-annealing)
The electrical conductivity of the sample after preliminary annealing was measured according to JIS H 0505. The energization in the measurement was performed in parallel with the rolling direction.

(Measurement of crystal orientation of products)
In the plate thickness direction surface layer and the plate thickness direction center, the area ratios of the Cube orientation, Copper orientation, and Brass orientation were measured by EBSD.
As a sample for analyzing the crystal orientation of the surface layer, the sample surface was mechanically polished to remove minute irregularities due to a rolling pattern or the like, and then finished to a mirror surface using colloidal silica abrasive grains. The resulting surface polishing depth was in the range of 2-3 μm.
In addition, as a sample for analyzing the crystal orientation of the central part of the plate thickness, from one surface to the central part of the plate thickness is removed by etching using a ferric chloride solution, and then mechanical polishing and colloidal silica abrasive grains are used. Finished to a mirror surface. The thickness of the sample after finishing was in the range of 45 to 55% with respect to the original plate thickness.
In the EBSD measurement, a sample area of 500 μm square containing 200 or more crystal grains was scanned in steps of 0.5 μm to analyze the orientation. 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 axis of rotation. This angle was taken as the deviation angle. A common rotation axis that can be expressed at the smallest angle is adopted. This deviation angle is calculated for all measurement points, and the first decimal place is an effective number. The total measurement area is the area of crystal grains having an orientation within 10 ° from each of the Cube orientation, Copper orientation, and Brass orientation. 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)
Tensile strength was measured in parallel with the rolling direction in accordance with JIS Z2241 using a tensile tester.

(Product notch bending test)
The test procedure is shown in FIG. A notching process with a depth of 1 / 3t was applied to the plate thickness t. The angle of the notch tip was 90 degrees, and a flat portion having a width of 0.1 mm was provided at the tip. Next, in accordance with JIS H3100, the inner bending radius was t, and a W bending test was performed in the Good Way direction (the bending axis was orthogonal to the rolling direction). Then, the bent section was finished to a mirror surface by mechanical polishing and buffing, and the presence or absence of cracks was observed with an optical microscope. The case where a crack was not recognized was evaluated as ○, and the case where a crack was observed was evaluated as ×.

(Product W-bending test)
In accordance with JIS H3100, the inner bending radius was t, and a W bending test was performed in the Good Way direction (the bending axis was orthogonal to the rolling direction). Then, the bent section was finished to a mirror surface by mechanical polishing and buffing, and the presence or absence of cracks was observed with an optical microscope. The case where a crack was not recognized was evaluated as ○, and the case where a crack was observed was evaluated as ×.

(Young's modulus measurement)
A strip-shaped sample having a thickness t, a width W (= 10 mm), and a length of 100 mm was collected so that the longitudinal direction was parallel to the rolling direction. One end of this sample is fixed, a load of P (= 0.15 N) is applied to a position of L (= 100 t) from the fixed end, and the Young's modulus E in the rolling parallel direction is calculated from the deflection d at this time using the following equation. Asked.
E = 4 · P · (L / t) ³ / (W · d)
Table 1 shows the evaluation results.

In each of the inventive examples, pre-annealing and light rolling were performed under the conditions specified by the present invention, the crystal orientation at the center of the plate thickness satisfied the specifications of the present invention, and cracking occurred in both W bending and notch bending. The tensile strength was as high as 800 MPa or higher, and a high Young's modulus exceeding 110 MPa was obtained.
In Comparative Example 1, since the degree of softening during pre-annealing was less than 0.25, the Copper azimuth area ratio in the central portion of the plate thickness exceeded 20%, and the Cube azimuth area ratio was less than 10%. In Comparative Example 2, since the degree of softening in the pre-annealing exceeded 0.75, the Brass orientation area ratio in the central portion of the plate thickness exceeded 20%. In Comparative Example 3, the degree of softening in the pre-annealing exceeded 0.75, and the electrical conductivity after the pre-annealing was less than 20% IACS, so that the area ratio of the Copper orientation and the Brass orientation in the central portion of the plate thickness was 20% The Cube orientation area ratio was less than 10%. In Comparative Examples 5 and 6, the degree of work of light rolling deviated from the definition of the present invention, and the Cube orientation area ratio in the center portion of the plate thickness was less than 10%. In the above comparative examples, cracks did not occur in W bending, but cracks occurred in notch bending. In addition, the preliminary annealing and light rolling of these comparative examples were performed within the range recommended by Patent Document 2, and the crystal orientation of the plate thickness surface layer satisfied the provisions of Patent Document 2.
In Comparative Example 4, the conductivity after the pre-annealing exceeded 45% IACS, so the Cube orientation area ratio exceeded 80% and the Young's modulus was a low value of less than 100 MPa.
Comparative Example 7 is a sheet thickness of 9 mm after surface grinding after hot rolling, and rolled as it is to 0.18 mm without pre-annealing and light rolling. In both the central part and the surface layer part, the area ratios of Copper orientation and Brass orientation exceeded 20%, and the Cube orientation area ratio became less than 10%. As a result, cracks occurred in both W bending and notch bending.

(Example 2)
It was examined whether the notch bendability improving effect shown in Example 1 could be obtained with Cu—Ni—Si alloys having different components and production conditions.
First, 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) Cold rolling (2) Pre-annealing: Insert the 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 and cool (water cooling) or leave the sample in the air for cooling Cooling was performed under two conditions (air cooling).
(3) Light rolling (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) Cold rolling (Rolling 1)
(6) 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.
(7) Cold rolling (Rolling 2)
(8) 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.

The same evaluation as in Example 1 was performed on the sample after the preliminary annealing and the product sample. Tables 2 and 3 show the evaluation results. When any one of rolling 1, rolling 2, and strain relief annealing is not performed, “none” is written in the column of the degree of processing or temperature.

Each of the inventive examples contains Ni and Si at a concentration specified by the present invention, and is subjected to pre-annealing and light rolling under the conditions specified by the present invention. Satisfactory, notch bending was possible, high tensile strength exceeding 650 MPa and high Young's modulus exceeding 110 MPa were obtained. Here, in Invention Example 15 in which the workability of Rolling 2 exceeded 50% and Invention Example 16 in which the workability of Rolling 1 exceeded 60%, although cracks occurred in the notch bending test, they were practically acceptable. Since it was a fine crack, it evaluated as (circle).
In Comparative Example 8, the light rolling workability exceeds 50%. Similar to the alloy of Example 1, the crystal orientation at the center of the plate thickness deviated from the provisions of the invention, and cracking occurred by notch bending. Compared to Invention Examples 15 and 16 of the same component, although the tensile strength was low, the generated cracks were remarkable at a level that hinders the function as an electronic component.
In Comparative Examples 9 and 10, the degree of softening in the pre-annealing did not satisfy the definition of the present invention. Similar to the alloy of Example 1, the crystal orientation at the center of the plate thickness deviated from the provisions of the invention, and cracking occurred by notch bending.
In Comparative Example 11, the Ni and Si concentrations were less than those of the present invention, and the notch bendability was good, but the tensile strength did not reach 500 MPa.

Claims (6)

1. It contains 0.8 to 4.5% by mass of Ni and 0.2 to 1.0% by mass of Si, and the balance is made of copper and inevitable impurities, and the cross-sectional position is 45 to 55% with respect to the plate thickness When the EBSD measurement is performed in the center of the plate thickness direction in parallel with the plate thickness direction and the crystal orientation is analyzed, the area ratio of the Cube orientation {0 0 1} <1 0 0> is 10 to 80%, and the Brass orientation A Cu—Ni—Si alloy having an area ratio of {1 1 0} <1 1 2> of 20% or less and a Copper orientation {1 1 2} <1 1 1> of 20% or less.
2. The total content of one or more of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, Cr, and Ag is 0.005 to 3.0 mass%. Cu-Ni-Si alloy.
3. An ingot containing 0.8 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, was prepared, and the ingot was heated to a temperature of 800 to 1000 ° C. After hot rolling to a thickness of 5 to 20 mm, cold rolling with a working degree of 30 to 99% is performed and heat treatment with a softening degree of 0.25 to 0.75 is performed to make the conductivity within a range of 20 to 45% IACS. After adjustment, cold rolling at a working degree of 7 to 50% is performed, followed by solution treatment at 700 to 900 ° C. for 5 to 300 seconds and aging treatment at 350 to 550 ° C. for 2 to 20 hours And
   The softening degree, the softening degree at the temperature T as S _T, method of manufacturing the Cu-Ni-Si-based alloy represented by the following formula:
   S _T = (σ ₀ −σ _T ) / (σ ₀ −σ ₉₀₀ )
   (Σ ₀ is the tensile strength before annealing, and σ _T and σ ₉₀₀ are the tensile strength after annealing at T ° C. and 900 ° C., respectively).
4. The ingot contains 0.005 to 3.0 mass% in total of at least one of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, Cr and Ag. A process for producing a Cu—Ni—Si based alloy as described in 1. above.
5. A copper product comprising the copper alloy according to claim 1 or 2.
6. An electronic device part comprising the copper alloy according to claim 1.

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