KR101808372B1 - Cu-Ni-Si BASED ALLOY AND PROCESS FOR MANUFACTURING SAME - Google Patents

Abstract

Cu-Ni-Si based alloy having high strength and high notch bendability, and a method of manufacturing the same. The Cu-Ni-Si alloy contains 0.8 to 4.5% by mass of Ni and 0.2 to 1.0% by mass of Si, the balance of copper and inevitable impurities, and has a cross-sectional position of 45 to 55% EBSD measurement was performed parallel to the plate thickness direction at the central portion in the thickness direction of the plate, and when the crystal orientation was analyzed, the area ratio of the Cube orientation {0 0 1} <1 0 0> was 10 to 80% The area ratio of the orientation {1 1 0} <1 1 2> is not more than 20%, and the area ratio of the copper orientation {1 1 2} <1 1 1> is not more than 20%.

Description

Cu-Ni-Si-based alloy and a method for manufacturing the same [0002]

The present invention relates to a lead frame material for a semiconductor device such as a conductive spring material such as a connector, a terminal, a relay, and a switch, a semiconductor device such as a transistor or an integrated circuit Copper alloy and a manufacturing method thereof.

BACKGROUND ART In recent years, miniaturization of electric and electronic parts has progressed, and copper alloy used for these parts has been required to have good strength, electric conductivity and bending workability. In accordance with this demand, there is an increasing demand for precipitation hardening type copper alloys such as Colson alloys having high strength and electrical conductivity instead of conventional solid solution copper alloys such as phosphor bronze and brass. The Cu-Ni-Si alloy, which is one of the Colson alloys, is an alloy in which compound particles of Ni and Si are precipitated in a Cu matrix, and has high strength, high conductivity, and good bending workability. Generally, strength and bending workability are opposite, 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 bending portion when the copper alloy plate is pressed to electronic or electronic parts such as a connector, the surface of the copper alloy plate is previously subjected to a cutting process called a notching process. (Hereinafter, also referred to as notch bending). This notch bending is widely used, for example, in press working of vehicle terminal. Since the copper alloy is worked and cured by notching to lose its ductility, cracks tend to occur in the copper alloy in the subsequent bending process. Therefore, the copper alloy used for notch bending is particularly required to have good bending workability.

Recently, as a technique for improving the bendability of a Cu-Ni-Si based alloy, a measure 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, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2006-283059) discloses a casting method in which (1) casting, (2) hot rolling, (3) cold rolling (95% (5) Cold rolling (20% or less), (6) Aging treatment, (7) Cold rolling (1 to 20% Is controlled to 50% or more to improve the bending workability.

In Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2011-17072), the area ratio of the Cube orientation is controlled to 5 to 60%, the area ratio of the Brass orientation and the Copper orientation is all controlled to 20% or less, And the bending workability is improved. (1) casting, (2) hot rolling, (3) cold rolling (85 to 99% of processing), (4) heat treatment at 300 to 700 ° C for 5 to 20 hours, 5) cold rolling (processing degree 5 to 35%), (6) solution treatment, (7) aging treatment, (8) cold rolling (processing degree 2 to 30%), and (9) The best bendability was obtained.

Japanese Patent Application Laid-Open No. 2006-283059 Japanese Laid-Open Patent Publication No. 2011-17072

The present inventors conducted a verification test on the effects of the above-described prior art. As a result, with regard to the technique of Patent Document 2, when the bending workability was evaluated by the W bending test, a certain improvement effect was confirmed. However, regarding the notch bending, the bending workability which can be considered to be sufficient was not obtained. Therefore, an object of the present invention is to provide a Cu-Ni-Si based alloy having high strength and high notch bendability and a method for producing the same.

In the prior art, the crystal orientation of the 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 Scattering Diffraction) refers to an electron back scattering diffraction (EBSD), which is determined by using a reflection electron Kick Drain Diffraction (Kikuchi pattern) generated when an electron beam is irradiated on a sample in an SEM (Scanning Electron Microscope) It is a technique to interpret bearing. Normally, the electron beam is irradiated on the surface of the copper alloy, and the information obtained at this time is azimuth information up to a depth of several 10 nm in which the electron beam enters, that is, bearing 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 with respect to notch bending. This is because the internal angle of the bending is moved to the inside of the plate by the notching process. Then, the crystal orientation at the central portion in the plate thickness direction was optimized for notch bending, and a manufacturing method for obtaining this crystal orientation was clarified.

The present invention has been completed in view of the above findings. In one aspect of the present invention, there is provided an aluminum alloy comprising 0.8 to 4.5% by mass of Ni and 0.2 to 1.0% by mass of Si, the balance being copper and inevitable impurities, EBSD measurement was performed in parallel with the plate thickness direction at the central portion in the plate thickness direction at a cross-sectional position of 50% to 55%, and when the crystal orientation was analyzed, the area ratio of the Cube orientation {0 0 1} <1 0 0> Cu-Ni-Si system having an area ratio of 10 to 80%, an area ratio of Brass orientation {1 1 0} <1 1 2> of 20% or less and an area ratio of copper orientation {1 1 2} <1 1 1> of 20% Alloy.

In one embodiment, the Cu-Ni-Si alloy according to the present invention contains at least one of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, 0.005 to 3.0% by mass.

According to another aspect of the present invention, there is provided an ingot including 0.8 to 4.5% by mass of Ni and 0.2 to 1.0% by mass of Si and the remainder being copper and inevitable impurities, Rolled to a thickness of 5 to 20 mm at a temperature of 100 ° C to a thickness of 5 to 20 mm and then cold rolled at a degree of processing of 30 to 99% and subjected to heat treatment at a softening degree of 0.25 to 0.75 to adjust the conductivity to a range of 20 to 45% IACS After the adjustment, cold rolling is carried out at a working rate of 7 to 50%, followed by a solution treatment at 700 to 900 DEG C for 5 to 300 seconds and an aging treatment at 350 to 550 DEG C for 2 to 20 hours Method,

The degree of softening is a method for producing a Cu-Ni-Si-based alloy represented by the following formula, with the degree of softening at temperature T being S _T :

S _T = (? _{0 -} ? _T ) / (? _{0 -} ? ₉₀₀ )

(σ ₀ is the tensile strength before annealing, σ _T and σ ₉₀₀ are the tensile strength after annealing at T ° C and 900 ° C, respectively).

A method of producing a Cu-Ni-Si alloy according to the present invention is a method of manufacturing a Cu-Ni-Si alloy according to one embodiment of the present invention, wherein the ingot is at least one of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, At least 0.005 to 3.0% by mass in total.

According to another aspect of the present invention, there is provided a new copper alloy product (copper alloy product) comprising the copper alloy.

According to another aspect of the present invention, there is provided an electronic device part comprising the copper alloy.

According to the present invention, it is possible to provide a Cu-Ni-Si-based alloy having high strength and high notch bendability and a method for producing the same.

1 is a graph showing the relationship between annealing temperature and tensile strength when an alloy according to the present invention is annealed at various temperatures.
2 is a view showing a test procedure of a notch bending test in the embodiment.

(Amount of addition of Ni and Si)

Ni and Si are precipitated as an intermetallic compound such as Ni ₂ Si by performing appropriate aging treatment. The strength improves by the action of the precipitate, and the Ni and Si solidified in the Cu matrix by the precipitation decrease, so that the conductivity is improved. However, when Ni is less than 0.8 mass% or Si is less than 0.2 mass%, desired strength can not be obtained. Conversely, when Ni exceeds 4.5 mass% or Si exceeds 1.0 mass%, the conductivity decreases. Therefore, in the Cu-Ni-Si 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%. The addition amount of Ni is preferably 1.0 to 4.0 mass%, and the amount of Si to be added is preferably 0.25 to 0.90 mass%.

(Other added elements)

Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, Cr and Ag contribute to the strength increase. Zn is effective for improving the heat peelability of Sn plating, Mg for improving stress relaxation property, and Zr, Cr and Mn for 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 mass%, the above effect can not be obtained. . Therefore, in the Cu-Ni-Si alloy according to the present invention, the total amount of these elements is preferably 0.005 to 3.0 mass%, more preferably 0.01 to 2.5 mass%.

(Crystal orientation)

The Cu-Ni-Si based alloy suppresses uneven deformation when the Cube orientation is large and the Brass orientation and the Copper orientation are small, and the bendability is improved. The Cube orientation is a state in which the (0 0 1) plane faces the rolling direction normal direction ND and the (1 0 0) plane faces the rolling direction RD, and {0 0 1} <1 0 0> . The Brass orientation is a state in which (1 1 0) faces ND and (1 1 2) faces RD, and is expressed by the exponent of {1 1 0} <1 1 2>. Copper bearing is a state in which the (1 1 2) plane faces to the ND and the (1 1 1) plane faces to the RD and is expressed by the exponent of {1 1 2} <1 1 1>.

When the area ratio of the Cube orientation in the central portion of the plate thickness is less than 10%, the notch bending property sharply decreases. On the other hand, if the area ratio of the Cube orientation in the central portion of the plate thickness exceeds 80%, the Young's modulus sharply decreases. When the Young's modulus deteriorates, there is a relation of P = E xd (P: spring force, E: Young's modulus, d: displacement), so that a desired spring force can not be obtained after machining with a component such as a connector. Therefore, the area ratio of the Cube orientation {0 0 1} <1 0 0> was set to 10 to 80%. The more preferable area ratio of the Cube orientation {0 0 1} <1 0 0> is 15 to 60%.

If any one of the area ratio of the copper orientation in the central portion of the plate thickness and the area ratio of the Brass orientation is more than 20%, the notch bending property sharply deteriorates. Therefore, the area ratio of the copper orientation and the area ratio of the Brass orientation were set to 20% or less. The area ratio of the copper orientation in the central portion of the plate thickness and the lower limit value of the area ratio of the Brass orientation are not regulated in terms of notch bending property but in the case of the alloy of the present invention, The area ratio of the copper orientation and the area ratio of the brass orientation do not become less than 1%. The area ratio of the copper orientation in the central portion of the plate thickness and the area ratio of the Brass orientation 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.

(Manufacturing method)

In a general manufacturing process of a Cu-Ni-Si-based alloy, a raw material such as electric copper, Ni, Si, or the like is first dissolved in a melting furnace to obtain a molten metal having a desired composition. Then, the molten metal is cast into an ingot. Thereafter, hot rolling, cold rolling, solution treatment and aging treatment are performed in the order of the desired thickness and properties in the order of foil or foil. After the heat treatment, the surface may be pickled or polished to remove the surface oxide film generated at the aging time. In order to increase the strength, cold rolling may be performed after the solution treatment and aging or aging.

In the present invention, the above-described crystal orientation is obtained by performing heat treatment (hereinafter also referred to as preliminary annealing) and cold rolling (hereinafter referred to as light rolling) at relatively low cost before the solution treatment.

The preliminary annealing is carried out for the purpose of partially producing recrystallized grains in a rolled structure formed by cold rolling after hot rolling. The ratio of the recrystallized grains in the rolled structure has an optimum value, and even if the ratio is excessively large or excessively large, the above-described crystal orientation can not be obtained. The recrystallized grains at the optimum ratio are obtained by adjusting the preliminary annealing conditions so that the softening degree S _T defined below is from 0.25 to 0.75.

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. The sample with the thermocouple attached thereto was inserted into a tubular furnace at 950 DEG C, and when the sample temperature measured at the thermocouple reached a predetermined temperature, the sample was taken out of the furnace, water cooled, and the tensile strength was measured. Recrystallization proceeded at a sample arrival temperature of 500 to 700 占 폚, and the tensile strength rapidly dropped. The gradual decrease in tensile strength on the high temperature side is due to the growth of recrystallized grains.

The softening degree S _T at the temperature T is defined by the following equation.

S _T = (? _{0 -} ? _T ) / (? _{0 -} ? 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 占 폚 is employed as the reference temperature for determining the tensile strength after recrystallization since the alloy according to the present invention is completely recrystallized by annealing at 900 占 폚.

When S _T is less than 0.25, particularly in the central portion of the plate thickness, the area ratio of the copper orientation is increased to exceed 20%, accompanied by a decrease in the area ratio of the Cube orientation.

When S _T is more than 0.75, especially in the central portion of the plate thickness, the area ratio of the Brass orientation is increased to exceed 20%, accompanied by a decrease in the area ratio of the Cube orientation.

Conductivity after pre-annealing is in the range of 20 ~ 45% IACS. When the conductivity becomes less than 20% IACS, the area ratio of the copper orientation and the brass orientation exceeds 20%, and the Cube bearing area ratio becomes less than 10%. If the pre-annealed conductivity exceeds 45% IACS, the area ratio of the Cube orientation exceeds 80%.

The temperature, time and cooling rate of the preliminary annealing are not particularly limited, and it is important to adjust the S _T and the conductivity to the above range. Generally, in the case of using a continuous annealing furnace, it is carried out at a furnace temperature range of 400 to 700 ° C for 5 seconds to 10 minutes, and in a batch annealing furnace at a furnace temperature of 350 to 600 ° C for 30 minutes to 20 hours .

After the annealing, prior to the solution treatment, a light rolling of 7 to 50% is carried out. The machinability R (%) is defined by the following formula.

_{R = (t 0 -t) /} t 0 × 1 0 0 (t 0: plate thickness before rolling, t: plate thickness after rolling)

If the processing degree deviates from this range, the area ratio of the Cube orientation in the central portion of the plate thickness becomes less than 10%.

The manufacturing method of the alloy of the present invention is listed as follows in the order of the process.

(1) Casting of ingots

(2) Hot rolling (temperature 800 ~ 100 ℃, thickness ~ 5 ~ 20 mm)

(3) Cold rolling (30 to 99% of processing degree)

(4) Pre-annealing (degree of softening: S _T = 0.25 to 0.75, conductivity = 20 to 45% IACS)

(5) Light rolling (7 to 50% processing)

(6) Solution treatment (at 700 to 900 ° C for 5 to 300 seconds)

(7) Cold rolling (1 to 60% of machining degree)

(8) Aging treatment (2 ~ 20 hours at 350 ~ 550 ℃)

(9) Cold rolling (1 to 50% of working)

(10) Deformation removal annealing (at a temperature of 300 to 700 ° C for 5 seconds to 10 hours)

Here, the degree of working of cold-rolled (3) is preferably 30 to 99%. In order to partially recrystallize the preliminary annealing 4, it is necessary to introduce a deformation into the cold rolling 3, and effective deformation is obtained at a processing degree of 30% or more. On the other hand, when the degree of processing exceeds 99%, cracks are generated on the edge of the rolled material and the like, and the material during rolling may be broken.

The cold rolling (7) and (9) are carried out arbitrarily for the purpose of high strength, and the strength is increased with the increase of the rolling degree, while the bendability is lowered. The effect of the present invention is obtained that the notch bendability is improved by controlling the crystal orientation of the central portion of the plate thickness irrespective of the presence or absence of cold rolling (7) and (9) and the degree of processing. Cold rolling (7) and (9) may or may not be performed. However, it is not preferable from the viewpoint of bending property that the degree of processing in each of the cold rolling (7) and (9) exceeds the upper limit value, and each degree of processing below the lower limit value is preferable I do not.

The deformation removing annealing 10 is carried out arbitrarily in order to recover the spring limit value or the like lowered by the cold rolling in the case of performing the cold rolling 9. The effect of the present invention is obtained that the notch bendability is improved by controlling the crystal orientation of the central portion of the plate thickness irrespective of whether or not the deformation removing annealing 10 is present. Deformation removal annealing 10 may or may not be performed.

Regarding the steps (2), (6), and (8), a general manufacturing condition of a Cu-Ni-Si alloy may be selected.

The Cu-Ni-Si based alloy of the present invention can be processed into various kinds of new products, for example, plates, rods, and foils. The Cu- , Terminals, relays, switches, and foil for secondary batteries.

Example

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

(Example 1)

An alloy containing 2.6% by mass of Ni, 0.58% by mass of Si, 0.5% by mass of Sn and 0.4% by mass of Zn and the balance of copper and inevitable impurities was used as an experimental material and subjected to preliminary annealing and light rolling The effect of crystal orientation on the bending property and mechanical properties of the product was studied.

2.5 kg of electric copper was dissolved in a high-frequency melting furnace in an argon atmosphere using a graphite crucible having an inner diameter of 60 mm and a depth of 200 mm. An alloying element was added to obtain the above alloy composition, the molten metal temperature was adjusted to 1300 캜, and the ingot was poured into a cast iron mold to prepare 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 占 폚 for 3 hours and hot-rolled to a thickness of 10 mm. The oxide scale on the surface of the hot-rolled plate was ground by a grinder and removed. The thickness after grinding was 9 mm. Thereafter, rolling and heat treatment were carried out in the following process order to prepare 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 process of light rolling.

(2) Preliminary annealing: A sample is placed in an electric furnace adjusted to a predetermined temperature, held for a predetermined time, put in a water bath and cooled (water cooling) And cooled.

(3) Light rolling: Cold rolling was carried out to various thicknesses of 0.18 ㎜ on various rolling mill roads.

(4) Solution treatment: A sample was inserted into an electric furnace adjusted to 800 DEG C and held for 10 seconds, and then the sample was cooled in a water bath.

(5) Aging treatment: An electric furnace was used and heated in an Ar atmosphere at 450 캜 for 5 hours.

(6) Cold Rolling: Cold rolling was performed from 0.18 mm to 0.15 mm at a processing rate of 17%.

(7) Deformation removal annealing: A sample was inserted into an electric furnace adjusted to 400 DEG C and held for 10 seconds, and then the sample was left in the atmosphere and cooled.

The following evaluation was carried out on the sample after the pre-annealing and the product sample (in this case, deformation-annealed).

(Softness evaluation in preliminary annealing)

The tensile strength of the specimen before and after the pre-annealing was measured by a tensile tester in accordance with JIS Z 2241 in parallel with the rolling direction, and the values were set to be σ ₀ and σ _T , respectively. The 900 占 폚 annealing sample was prepared in the above procedure (water cooled by inserting the sample into the furnace at 950 占 폚 and reaching 900 占 폚), and the tensile strength was measured in parallel with the rolling direction to obtain? ₉₀₀ . From the values of σ ₀ , σ _T and σ ₉₀₀ , the softening degree S _T was obtained.

S _T = (? _{0 -} ? _T ) / (? _{0 -} ? ₉₀₀ )

(Conductivity measurement after preliminary annealing)

The conductivity after the pre-annealing was measured according to JIS H 0505. Energization in the measurement was carried out in parallel with the rolling direction.

(Measurement of crystal orientation of product)

The area ratio of the Cube orientation, Copper orientation and Brass orientation in the plate thickness direction surface layer and the plate thickness direction center portion was measured by EBSD.

As a sample for analyzing the crystal orientation of the surface layer, the surface of the sample was mechanically polished to remove minute irregularities such as a rolling shape, and then finished with a mirror surface using colloidal silica abrasive grains. The polishing depth of the surface was in the range of 2 to 3 탆.

As a sample for analyzing the crystal orientation of the central portion of the plate thickness, the area from one surface to the center of the plate thickness was removed by etching using a ferric chloride solution, and thereafter, by mechanical polishing and colloidal silica abrasion, Respectively. 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, the orientation was analyzed by scanning at a step size of 0.5 mu m for a sample area of 500 mu m square including 200 or more crystal grains. With respect to the deviation angle from the ideal orientation, the rotation angle was calculated around the common rotation axis to obtain the deviation angle. For example, with respect to the S orientation (2 3 1) [6 -4 3], (1 2 1) [1 -1 1] assumes the relationship of (20 10 17) And this angle was defined as a deviation angle. A common rotation axis can be expressed by the smallest shift angle. This deviation angle is calculated for all measurement points, and the area up to the first decimal point is defined as an effective number, and the area of the crystal grains having an orientation within 10 degrees from each of the Cube orientation, Copper orientation and Brass orientation is divided by the total measurement area, Respectively. The information obtained in the orientation analysis by the EBSD includes azimuth information up to a depth of several tens of nm at which the electron beam enters the sample, but is described as the area ratio because it is sufficiently small for the area to be measured.

(Tensile test of the product)

The tensile strength was measured in parallel with the rolling direction in accordance with JIS Z2241 using a tensile tester.

(Notch bending test of product)

The test procedure is shown in Fig. A notching process with a depth of 1/3 t was performed on the plate thickness t. An angle of the tip of the notch was 90 degrees, and a flat portion having a width of 0.1 mm was formed at the tip. Next, in accordance with JIS H3100, the W bending test was performed in the Good Way direction (the bending axis was orthogonal to the rolling direction) with the bend radius set at t. Then, the bent section was finished with a mirror-finished surface by mechanical polishing and buff polishing, and the presence or absence of cracks was observed with an optical microscope. The case where no crack was confirmed was evaluated as &amp; cir &amp; and the case where cracks were confirmed was evaluated as &quot; X &quot;.

(W bending test of product)

According to JIS H3100, the bending test was carried out in the Good Way direction (the bending axis is orthogonal to the rolling direction) with the bend radius being t. Then, the bent section was finished with a mirror-finished surface by mechanical polishing and buff polishing, and the presence or absence of cracks was observed with an optical microscope. The case where no crack was confirmed was evaluated as &amp; cir &amp; and the case where cracks were confirmed was evaluated as &quot; X &quot;.

(Young's modulus measurement)

A sample having a strip shape having a plate thickness t, a width W (= 10 mm) and a length of 100 mm was sampled so that the longitudinal direction was parallel to the rolling direction. One end of the specimen was fixed and a load of P (= 0.15 N) was added to the position of L (= 100 t) from the fixed end. From the flexure (d) at this time, Was obtained.

E = 4 · P · (L / t) ³ / (W · d)

Table 1 shows the evaluation results.

In the present invention, preliminary annealing and light rolling were performed under the conditions specified by the present invention, and the crystal orientation of the central portion of the plate thickness satisfies the requirements of the present invention, cracks do not occur in both W bending and notch bending, Was as high as 800 MPa or more and a high Young's modulus exceeding 110 MPa was obtained.

In Comparative Example 1, since the degree of softening in the preliminary annealing was less than 0.25, the Copper bearing area ratio at the central portion of the plate thickness exceeded 20% and the Cube bearing area ratio was less than 10%. In Comparative Example 2, since the degree of softening in the preliminary annealing exceeded 0.75, the Brass bearing surface area ratio at the central portion of the plate thickness exceeded 20%. In Comparative Example 3, since the degree of softening in the preliminary annealing was more than 0.75 and the conductivity after the preliminary annealing was less than 20% IACS, the area ratio of the copper orientation and the brass orientation in the central portion of the plate thickness exceeded 20% , And the Cube bearing area ratio was less than 10%. In Comparative Examples 5 and 6, the degree of processing of the light-rolling was deviated from the specification of the present invention, and the Cube bearing surface area ratio at the central portion of the plate thickness was less than 10%. In the above comparative example, cracks did not occur in W bending, but cracks occurred in notch bending. The preliminary annealing and light rolling of these comparative examples were carried out within the range of conditions recommended by Patent Document 2, and the crystal orientation of the surface layer of the plate thickness satisfied the requirements of Patent Document 2. [

In Comparative Example 4, since the conductivity after pre-annealing exceeded 45% IACS, the Cube bearing area ratio exceeded 80% and the Young's modulus became a low value of less than 100 MPa.

In Comparative Example 7, after the hot-rolled surface grinding, the sheet was rolled up to a plate thickness of 0.18 mm without being pre-annealed and lightly rolled from a thickness of 9 mm. The area ratio of the copper orientation and the brass orientation exceeded 20% and the Cube orientation area ratio became less than 10% in both the plate thickness central portion and the surface layer portion. As a result, cracks occurred in both the W bending and the notch bending.

(Example 2)

It was examined whether or not the effect of improving the notch bending property as shown in Example 1 can be obtained also in Cu-Ni-Si alloys with different components and manufacturing conditions.

First, casting, hot rolling and surface grinding were carried out in the same manner as in Example 1 to obtain a plate having a thickness of 9 mm and 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 thickness shown in Table 2. [

(1) cold rolling

(2) Preliminary annealing: A sample is placed in an electric furnace adjusted to a predetermined temperature, held for a predetermined time, put in a water bath and cooled (water cooled) Lt; / RTI &gt;

(3) Light rolling

(4) Solution treatment: A sample was inserted into an electric furnace adjusted to a predetermined temperature and held for 10 seconds, and then the sample was cooled in a water bath. The temperature was selected within a range in which the average diameter of recrystallized grains was in the range of 5 to 25 mu m.

(5) Cold rolling (rolling 1)

(6) Aging treatment: An electric furnace was used for heating in an Ar atmosphere at a predetermined temperature for 5 hours. The temperature was chosen so that the tensile strength after aging was at a maximum.

(7) Cold rolling (rolling 2)

(8) Deformation removal annealing: After inserting a sample into an electric furnace adjusted to a predetermined temperature and keeping it for 10 seconds, the sample was allowed to stand in the atmosphere and cooled.

The samples and the product samples after the pre-annealing were evaluated in the same manner as in Example 1. Tables 2 and 3 show the evaluation results. When either rolling 1, rolling 2 or deformation-removing annealing is not carried out, "No" is written in the column of each degree of processing or temperature.

The present invention has been accomplished by preliminary annealing and light rolling under the conditions specified by the present invention and containing Ni and Si at the concentrations specified by the present invention. The crystal orientation of the central portion of the plate thickness satisfies the requirements of the present invention, Notched bending, high tensile strength exceeding 650 MPa, and high Young's modulus exceeding 110 MPa were obtained. In the inventive example 15 in which the degree of processing of the rolled steel 2 exceeds 50% and in the case of the steels 16 in which the degree of processing of the rolled steel 1 exceeds 60%, cracks occurred in the notch bending test, Since it was a fine crack, it was evaluated as?.

In Comparative Example 8, the working degree of light-rolled steel exceeded 50%. As in the case of the alloy of Example 1, the crystal orientation of the central portion of the plate thickness deviated from the specification of the present invention, and cracks were generated by notch bending. Compared with the inventive examples 15 and 16 of the same components, although the tensile strength was low, the generated cracks remarkably hindered the function as an electronic part.

In Comparative Examples 9 and 10, the degree of softening in the preliminary annealing did not satisfy the requirements of the present invention. As in the case of the alloy of Example 1, the crystal orientation of the central portion of the plate thickness deviated from the specification of the invention, and cracks were generated by notch bending.

In Comparative Example 11, the Ni and Si concentrations were below those of the present invention, and the notch bendability was good, but the tensile strength did not reach 500 MPa.

Claims (6)

0.8 to 4.5% by mass of Ni and 0.2 to 1.0% by mass of Si, the balance being copper and inevitable impurities, and having a cross-sectional position of 45 to 55% EBSD measurement was performed in parallel with the plate thickness direction. When the crystal orientation was analyzed, the area ratio of the Cube orientation {0 0 1} <1 0 0> was 10 to 80%, the Brass orientation {1 1 0} <1 1 2> is not more than 20%, and the area ratio of the copper orientation {1 1 2} <1 1 1> is not more than 20%. The method according to claim 1,
Cu-Ni-Si-based alloy containing 0.005 to 3.0 mass% of at least one of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, Cr and Ag in a total amount. An ingot containing 0.8 to 4.5% by mass of Ni and 0.2 to 1.0% by mass of Si and the balance of copper and inevitable impurities is prepared and the ingot is heated at a temperature of 800 to 1000 캜 to a thickness of 5 to 20 mm , Cold rolling at a degree of processing of 30 to 99% is carried out and a heat treatment is performed at a softening degree of 0.25 to 0.75 to adjust the conductivity to a range of 20 to 45% IACS. Cold rolling, followed by solution treatment at 700 to 900 占 폚 for 5 to 300 seconds and aging treatment at 350 to 550 占 폚 for 2 to 20 hours,
The degree of softening is defined as a softening degree at a temperature T of S _T , and a manufacturing method of a Cu-Ni-Si-based alloy represented by the following formula:
S _T = (? _{0 -} ? _T ) / (? _{0 -} ? ₉₀₀ )
(σ ₀ is the tensile strength before annealing, σ _T and σ ₉₀₀ are the tensile strength after annealing at T ° C and 900 ° C, respectively). The method of claim 3,
Wherein the ingot is a Cu-Ni-Si alloy containing 0.005 to 3.0 mass% of at least one of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Gt; A novelty product comprising the copper alloy according to any one of claims 1 to 3. An electronic device part having the copper alloy according to claim 1 or 2.

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