KR101590242B1 - Cu-Ni-Si ALLOY WIRE HAVING EXCELLENT BENDABILITY - Google Patents

Abstract

The present invention aims at a Cu-Ni-Si-based alloy exhibiting improved bending workability even when notched. The present invention relates to a method for manufacturing a semiconductor device, which comprises 1.0 to 4.5% of Ni, 0.2 to 1.0% of Si, and the balance of copper and unavoidable impurities, The maximum value of the X-ray random intensity ratio in the range of the axis rotation angle alpha of 0 to 10 degrees perpendicular to the rotation axis of the meter is 3.0 to 15.0. Preferably, the number of inclusions having a particle diameter of 1 to 2 占 퐉 is 50 to 200 Mm 2 and at least one of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, Cr and Ag may be contained in an amount of 0.005 to 2.5% in total. After the hot rolling, the alloy bath is cooled to 600 to 300 ° C at a rate of 10 to 100 ° C / min, cold-rolled at a deformation rate of 1 × 10 ^-6 to 1 × 10 ^-4 / s, , And finally cold rolling, and then annealing may be performed.

Description

Cu-Ni-Si ALLOY WIRE HAVING EXCELLENT BENDABILITY, which is excellent in bending workability.

The present invention relates to a Cu-Ni-Si alloy alloy preferable as a material for a connector, a terminal, a relay, and a switch.

BACKGROUND ART [0002] With the recent miniaturization of electronic devices, miniaturization of electric and electronic parts is progressing. The copper alloy used for these parts is required to have good strength and electrical conductivity.

In the case of the in-vehicle terminal, along with miniaturization, the copper alloy to be used needs to have good strength and electrical conductivity. Further, in the case of the female arm terminal for automobile, the bending inner surface is often subjected to a notch machining process called a notching process before the press bending process. This is a process carried out to improve the shape accuracy after press bending. With the miniaturization of the product, the notching process tends to be deepened to further improve the shape accuracy of the terminal. Therefore, the copper alloy used for the vehicle-use arm terminals is required to have good bending workability in addition to good strength and electrical conductivity.

In response to this demand, a precipitation hardening type copper alloy such as a Korson alloy having high strength and electrical conductivity is used instead of the conventional solid solution copper alloy such as phosphor bronze or brass, and the demand thereof is increasing. Among the Korson alloys, the Cu-Ni-Si alloy is an alloy system having a high strength and a relatively high conductivity. The strengthening mechanism improves the strength and the conductivity by depositing Ni-Si intermetallic compound particles in the Cu matrix .

In general, strength and bending workability are opposite to each other, and it is desired to improve the bending workability of Cu-Ni-Si based alloy while maintaining high strength.

As a method for improving the bending workability of a Cu-Ni-Si alloy, there is a method of controlling the crystal orientation as described in Patent Documents 1 to 3. [ In Patent Document 1, by setting the area ratio of {001} <100> of the measurement result of the EBSP analysis to 50% or more, in Patent Document 2, the area ratio of {001} <100> The area ratio of {110} <112> of the measurement result of EBSP analysis is 20% or less, the area ratio of {121} <111> is 20% or less, {001 } &Lt; 100 &gt; is 5 to 60%, the bending workability is improved.

Japanese Patent Application Laid-Open No. 2006-283059 Japanese Laid-Open Patent Publication No. 2006-152392 Japanese Laid-Open Patent Publication No. 2011-017072

However, in these methods, when the bending process is performed after the notching process, cracks are generated in the bending process portion. Especially, when the notch depth of the notching process is long, large cracks are generated, and improvement in the bending processability is insufficient in these methods.

Therefore, the object of the present invention is to improve the bending workability of a Cu-Ni-Si based alloy, particularly to improve the bending workability in the case of performing notching.

The inventors of the present invention investigated the relationship between the crystal orientation of the Cu-Ni-Si based alloy and the bending workability and found that the {001} &lt; 100 &gt; It has been found that the bending workability is improved by controlling the maximum value of the X-ray random intensity ratio of the region including the orientation, in particular, the bending workability after the notching processing is improved.

In order to control the X-ray random intensity ratio at both the surface layer and the center, it is preferable to control the deformation rate of the cold rolling after hot rolling by cooling the material at a specific speed after the hot rolling to have a specific amount of inclusions having a particle diameter of 1 to 2 占 퐉 I found something effective.

That is, the present invention relates to the following invention.

(1) Ni: 1.0 to 4.5 mass% and Si: 0.2 to 1.0 mass%, the balance being copper and inevitable impurities, and in both the surface layer and the center, A Cu-Ni-Si-based alloy having an excellent X-ray random intensity ratio of 3.0 to 15.0 and an excellent bending workability in a range of 0 to 10 degrees of axis rotation perpendicular to the rotational axis of the diffraction goniometer article.

(2) The Cu-Ni-Si alloy alloy according to (1), wherein the number of inclusions parallel to the rolling direction and parallel to the plate thickness direction and having a diameter of 1 to 2 占 퐉 is 50 to 200 number / mm2.

(3) A method for producing an alloy according to (1) or (2), which comprises 0.005 to 2.5 mass% of at least one of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, The Cu-Ni-Si-based alloy tank described above.

Cracking does not occur even when the inner surface of the bend is notched before press bending, and a Cu-Ni-Si alloy excellent in bendability can be obtained.

Fig. 1 is a {200} positive electrode point drawing showing a range of 0 to 10 degrees of the axis rotation angle perpendicular to the rotation axis of the diffraction goniometer according to the Schultz method as a gray portion (in the center circle).
2A is a schematic view of a notch processing step. Arrows in the figure indicate pressure directions.
Figure 2B is a schematic view of a 90 ° W bending process.

(1) Ni and Si concentration

Ni and Si are precipitated as an intermetallic compound such as Ni ₂ Si by aging treatment. This compound improves the strength, and as it precipitates, the Ni and Si solidified in the Cu matrix decrease, so that the conductivity is improved. However, if the Ni concentration is less than 1.0% by mass (expressed as%) or the Si concentration is less than 0.2%, desired strength can not be obtained. Conversely, if the Ni concentration exceeds 4.5% or the Si concentration exceeds 1.0% The hot workability deteriorates.

(2) Other added elements

The addition of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, Cr and Ag contributes to the strength increase. In addition, 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 concentration of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, Cr and Ag is less than 0.005%, the above effect can not be obtained. Conversely, And can not be used as materials for electric and electronic parts.

(3) X-ray random intensity ratio

It is effective to increase the maximum value of the X-ray random intensity ratio of the region including the {001} &lt; 100 &gt; orientation on the {200} positive electrode point drawing in order to improve the bending workability, particularly the bending workability after the notching processing. Also, in both the surface layer and the center portion, it is effective to improve the bending workability after the notching process by increasing the X-ray random intensity ratio. In the present specification, the term &quot; surface layer &quot; refers to a portion up to 1/6 depth from the front surface of the substrate to the center of the plate thickness, and &quot; center portion &quot; Further, the {001} &lt; 100 &gt; orientation on the {200} positive electrode point drawing indicates the angle of the axis rotation perpendicular to the rotation axis of the diffraction goniometer defined by the Schultz method and the angle ? = 0 to 10 degrees, and? = 0 to 360 degrees.

(X-ray diffractometer (RINT2500, manufactured by Rigaku Corporation) in the surface layer and the central part, X in the range of 0 to 10 deg. (See Fig. 1) on the {200} It has been found that when the maximum value of the linear random intensity ratio is 3.0 or more, the bending workability is good. If the maximum value is less than 3.0, the bending workability deteriorates. On the other hand, it is difficult to actually exceed the maximum value of 15.0. Therefore, the upper limit of the maximum value is 15.0. Preferably, the maximum value in both the surface layer and the center portion is 5.0 or more.

The reason for achieving excellent bending crack resistance by adjusting the X-ray random intensity ratio of the {001} &lt; 100 &gt; orientation is not clear, but the {001} &lt; 100 & It is considered that cracks do not occur at the time of bending. However, the present invention is not limited by the above theory. The ranges of? And? Were determined in consideration of the fluctuation of the peak positions of the X-ray intensity ratio from processing, heat treatment conditions and measurement errors.

The notch depth obtained by the notching process, which is conventionally performed in the terminal manufacturing process, reaches the central portion of the plate thickness in a deep one. Even when the maximum value of the X-ray random intensity ratio of the surface layer only is increased, micro cracks are generated in the central portion of the plate thickness at the time of notching, and this is propagated to the surface layer in the bending process after the notching process. Therefore, it is effective to improve the bending workability to adjust the crystal orientation by increasing the maximum value of the X-ray random intensity ratio in both the surface layer and the center portion.

On the other hand, in Patent Documents 1 to 3, the crystal orientation of the surface was controlled and measured, and the crystal orientation of the central portion was not controlled (each of Claims 1 to 3 of Patent Documents 1 to 3). For this reason, in the bending process after the notching process, micro cracks are generated in the central portion of the plate thickness, and the bending workability is poor.

(4) Inclusion

In the present invention, the term &quot; inclusive &quot; refers to generally coarse crystallization products produced in the solidification process during casting, oxides and sulfides generated by reaction in the molten metal during melting, As a concept including a precipitate produced by the precipitation reaction in the solid phase matrix during the cooling process after the solidification process of the Si phase, that is, the cooling process after solidification, the hot rolling process, the cooling process after the solution process, and the aging process, (So-called second phase particles) that are observed in the matrix by means of the particles. &Quot; Particle size of inclusions &quot; refers to the minimum diameter of the inclusions measured under SEM observation. Quot; number of inclusions &quot; is the average number of particles per unit square mm actually calculated for particles different in shape from the parent phase by SEM observation after etching in a cross section parallel to the rolling direction of the material and parallel to the plate thickness direction .

As described above, the inclusions of the present invention also include particles formed in a process after hot rolling. What is mainly contributed to the aimed action in the present invention is inclusions of a certain size existing after hot rolling.

Concretely, when the number of inclusions having a particle diameter of 1 to 2 占 퐉 is 50 to 200 pieces / mm2 in the rolling parallel cross section after hot rolling, the maximum value of the X-ray random intensity ratio in both the surface layer and the center portion becomes 3.0 or more. Mm &lt; 2 &gt; / mm &lt; 2 &gt;, the maximum value of the X-ray random intensity ratio becomes less than 3.0, and the bending workability is deteriorated.

The number of inclusions having a particle size exceeding 1 占 퐉 after hot-rolling is almost the same as the number of the final products obtained through the production process of a Cu-Ni-Si alloy including cold rolling, solution treatment and aging treatment.

Specifically, when cold rolling is performed on a material having an inclined particle diameter of 1 to 2 占 퐉 uniformly distributed in the thickness direction of the steel sheet after hot rolling, the deformation is integrated in the periphery of the inclusions, . When the solution is subjected to the solution treatment, the crystal grains of the {001} &lt; 100 &gt; orientation are uniformly recrystallized in the plate thickness direction, so that the X-ray intensity ratio within the above range can be obtained.

However, if there is a coarse inclusion having a grain size of 1 to 2 占 퐉 after the hot rolling of the precipitation hardening type copper alloy in the related art, the fine second phase particles are not sufficiently precipitated in the subsequent solution treatment step, It is thought that the bending workability is deteriorated because there is a fear that the bending workability is reduced and the bending work becomes a starting point of the crack. For this reason, in the production step of the precipitation-strengthening type copper alloy, sufficient heat is applied during hot rolling so that inclusions are not generated as much as possible after hot rolling, and quenched by hot water after hot rolling.

The above Patent Documents 1 to 3 do not pay attention to the conditions of the hot rolling step and control the crystal orientation of the rolled surface by controlling only the rolling degree or the solution treatment condition. However, in cold rolling after hot rolling, the crystal orientations of the surface layer and the center portion are different from each other because the processing deformation occurring in the surface layer and the center portion is different unless the deformation rate is controlled. In the solution treatment, the amount of heat received by the surface layer differs from that in the central portion, so that the desired crystal orientation can not be attained in the central portion where the influence of the heat amount is small. Therefore, in the manufacturing method of these patent documents, the crystal orientation of the central portion can not be controlled, and the maximum value of the X-ray random intensity ratio of the region including the {001} &lt; 100 &gt; orientation does not increase at the central portion.

(5) Manufacturing process

In the manufacturing process of the present invention, first, a raw material such as electric copper, Ni, Si, or the like is dissolved in an atmosphere melting furnace under coated with charcoal to obtain a molten metal having a desired composition. Then, the molten metal is cast into an ingot. Then, hot rolling is carried out and cold rolling and solution treatment (700 to 1,000 占 폚 for 10 to 300 seconds), aging treatment (350 to 550 占 폚 for 2 to 20 hours), final cold rolling %). Deformation removing annealing may be performed after the final cold rolling. Deformation-removing annealing is usually carried out at 250 to 600 DEG C for 5 to 300 seconds in an inert atmosphere such as Ar. Cold rolling may be carried out between the solution treatment and the aging treatment to increase the strength. After the solution treatment, final cold rolling and aging treatment may be carried out in this order, and the order of these steps may be changed. Rolled under the following conditions and subjected to cold rolling after the cold rolling in the following conditions, as long as it is employed in the manufacturing process of the Cu-Ni-Si alloy and is within the range of the usual solution treatment, aging treatment and final cold rolling as exemplified above The crystal grains of the desired orientation in both the surface layer and the center portion are recrystallized by the solution treatment, and the structure of the crystal orientation does not essentially change even after the aging treatment and the final cold rolling.

Hereinafter, the manufacturing conditions of the process which becomes very important in the method of manufacturing the alloy bath of the present invention will be described in detail.

(A) Hot rolling

The ingot is heated at 800 to 1,000 DEG C for 1 to 20 hours, homogenized and annealed, followed by rolling. After the rolling, the cooling rate during the reduction of the material temperature from 600 to 300 占 폚 is preferably 10 to 100 占 폚 / min, more preferably 20 to 80 占 폚 / min. When the cooling rate is out of the above range, inclusions having a particle diameter of 1 to 2 占 퐉 tend to fall outside the range of 50 to 200 number / mm2. That is, when the cooling rate is high, inclusions having a particle diameter of 1 to 2 占 퐉 become less than 50 pieces / mm2, so that uniform deformation can not be caused in the plate thickness direction in the next cold rolling step, and inclusions having a particle diameter of 1 to 2 占 퐉 Mm &lt; 2 &gt; / mm &lt; 2 &gt;, it is impossible to generate uniform deformation in the thickness direction in the subsequent cold rolling step, and the bendability decreases.

(B) Cold rolling after hot rolling

The deformation rate of cold rolling after hot rolling is preferably 1 x 10 ^-6 to 1 x 10 ^-4 / s, more preferably 5 x 10 ^-5 to 8.0 x 10 ^-5 / s. In the present invention, the &quot; deformation rate &quot; is specified as the rolling speed / roll contact arc (arc) length. When the strain rate is less than 1 x ^10-6 / s, the maximum value of the X-ray random intensity ratio of the obtained material is 3.0 or more in the surface layer but less than 3.0 in the central portion. On the other hand, if it exceeds 1 × 10 ^-4 / s, the maximum value of the X-ray random intensity ratio of the obtained material is 3.0 or more at the central portion, but is undesirable because it is less than 3.0 in the surface layer.

Example

Examples of the present invention will now be described with reference to comparative examples, which are provided for a better understanding of the present invention and its advantages, and are not intended to limit the invention.

In the high-frequency melting furnace, 2.50 kg of electric copper was dissolved in an alumina or magnesia crucible having an inner diameter of 110 mm and a depth of 230 mm under an argon atmosphere. An element other than copper was added in accordance with the composition shown in Table 1 and the molten metal temperature was adjusted to 1,300 DEG C and the molten metal was cast into an ingot having a size of 30 x 60 x 120 mm using a mold (cast iron) To prepare a copper alloy bath.

(Step 1) After heating at 950 占 폚 for 3 hours, hot-rolling to a thickness of 10 mm, the cooling rate until the material temperature was lowered from 600 占 폚 to 300 占 폚 was changed as shown in Table 1.

(Process 2) The oxide scale of the surface of the plate after hot rolling was grinded and removed by a grinder.

(Step 3) Cold-rolled to a plate thickness of 0.180 mm at a deformation rate shown in Table 1. The strain rate was determined from rolling speed / roll contact arc length.

(Step 4) As a solution treatment, heating was conducted at 800 캜 for 10 seconds in the air, and quenched in water.

(Step 5) As the aging treatment, an electric furnace was used and heated in an Ar atmosphere at 450 占 폚 for 5 hours.

(Step 6) Final cold rolling was performed to a thickness of 0.15 mm.

(Step 7) As deformation-removing annealing, heating was performed in an Ar atmosphere at 400 DEG C for 10 seconds.

The samples thus prepared were evaluated for various properties as follows.

(1) Inclusion

In the sample after hot rolling, the texture of the cross section parallel to the rolling direction and parallel to the plate thickness direction was developed by etching (water-ferric chloride), and FE-SEM (manufactured by Nihon FEI, XL30SFEG ) Was used to observe secondary electron images of a field of 1 mm 2 at a magnification of 750 times. Thereafter, the particle diameters and the number of inclusions in the observation field of view were obtained by using an image analyzer. The inclusion of the product after the final process was also measured, but it was confirmed that the number of inclusions having a particle size of 1 to 2 占 퐉 after hot rolling did not change much after the final process.

(2) the maximum value of the X-ray random intensity ratio

Using a Co sphere using an X-ray diffractometer (RINT2500, manufactured by Rigaku Corporation), the {200} positive electrode point of each sample was measured at a tube voltage of 30 kV and a tube current of 100 mA , And a {200} positive electrode point drawing was made. The X-ray intensity within the above-mentioned range was measured, and the ratio of the copper powder (Copper (powder) 2N5, manufactured by Kanto Kagaku Co., Ltd.) and the X-ray intensity measured in the same manner as the standard sample was calculated and the maximum value was obtained. The maximum value of the X-ray random intensity ratio of the surface layer is the rolled surface and the maximum value of the X-ray random intensity ratio of the central portion is the surface exposed to the center of the plate thickness (1/2 of the plate thickness depth) by spray etching of the ferric chloride solution Respectively. The measurement of the rolled surface was carried out after the surface of the rolled surface was exposed to a solution of 67% phosphoric acid + 10% sulfuric acid + water at 15 V for 60 seconds by electrolytic polishing, followed by washing with water and drying.

(3) 0.2% proof and conductivity

The 0.2% proof stress was measured in accordance with JIS Z 2241 using a tensile tester. The good strength in the present invention means that the 0.2% proof stress is in the range of 600 to 950 MPa, preferably 700 to 950 MPa.

The conductivity was measured according to JIS H 0505. In the present invention, the preferable conductivity means 30% IACS or more, preferably 35% IACS or more.

(4) Bendability

As the evaluation of the bending property, notching processing was performed at depths of 25, 50 and 75 탆 (see Fig. 2A). Thereafter, in accordance with JIS H 3130, bending with a bending radius of 0 mm and 90 W in the direction of Good Way was performed (see Fig. 2B). In FIG. 2A, the sample to which the notch is applied is turned upside down in FIG. 2B. The cross section in the direction parallel to the rolling direction of the bent portion and parallel to the plate thickness direction was mirror-finished by mechanical polishing and buff polishing, and the presence or absence of cracks was observed with an optical microscope (magnification: 50 times). The case where no cracks were observed in the optical microscope observation was evaluated as &amp; cir &amp;

In the present invention, &quot; excellent bending workability &quot; means that cracks can not be confirmed even in a notching process with a depth of 50 mu m when the above evaluation is performed on a sample having a thickness of 0.15 mm.

Examples are shown in Table 1. Inventive Examples 1 to 23 were within the specified range, and cracking was not confirmed even after the bending process was performed after the notching process, thereby exhibiting excellent bending workability.

In Comparative Example 1, the Ni and Si concentrations were all low, so the 0.2% proof stress was low. In Comparative Example 2, cracks occurred during hot rolling because both Ni and Si concentrations were high. In Comparative Example 3, the conductivity was low because the concentrations of the additive elements other than Ni and Si were high, and these were unsuitable as materials for electric and electronic parts.

Comparative Example 4 is an example in which the number of inclusions was large because the cooling rate of the hot rolling was slow. The maximum value of the X-ray random intensity ratio was less than 3.0 at the center portion in the surface layer, and the bending workability was bad. On the contrary, Comparative Examples 5 and 6 are examples of the prior art that were cooled after hot rolling. The number of inclusions was small because the cooling rate was high and the maximum value of the X-ray random intensity ratio was less than 3.0 at the center portion in the surface layer even if the deformation rate of the cold rolling was within an appropriate range.

Comparative Examples 7 and 8 are examples in which the deformation rate of cold rolling after hot rolling was fast. The maximum value of the X-ray random intensity ratio at the center portion was 3.0 or more, but the surface layer portion was less than 3.0, and the bending workability was bad even at the notching depth of 25 占 퐉 (1/6 of the plate thickness). In contrast, Comparative Examples 9 and 10 are examples in which the deformation rate of cold rolling after hot rolling was slow. Although the maximum value of the X-ray random intensity ratio of the surface layer portion was 3.0 or more, the center portion was less than 3.0, and cracking did not occur at a notching processing depth of 25 占 퐉, but cracks occurred at 50 占 퐉 (1/3 of the plate thickness) The bending workability was bad.

Comparative Example 11 is an example in which the maximum value of the X-ray random intensity ratio of the surface layer is adjusted to 3.0 or more by controlling the deformation rate of the cold rolling after the hot rolling is carried out in the same manner as in Patent Documents 1 to 3. Since the maximum value of the X-ray random intensity ratio at the center portion was less than 3.0, cracks occurred at a notching processing depth of 50 占 퐉 or more, and the bending workability after the notching processing was bad.

Industrial availability

The Cu-Ni-Si based copper alloy of the present invention is preferable as a material for a connector, a terminal, a relay, a switch and the like because cracking does not occur even when the inner surface of the bend is notched before the press bending process and the bendability is excellent.

S: Sample
d: Notching depth

Claims (3)

The balance of Ni and 1.0 to 4.5% by mass of Si and 0.2 to 1.0% by mass of Si, the balance of copper and inevitable impurities, and in both the surface layer and the center, the {200} The maximum value of the X-ray random intensity ratio in the range of the axis rotation angle? Of 0 to 10 degrees perpendicular to the rotation axis of the diffraction goniometer is 3.0 to 15.0, and the maximum value of the cross-section parallel to the rolling direction A Cu-Ni-Si alloy alloy having excellent bending workability with a number of inclusions having a particle diameter of 1 to 2 占 퐉 of 50 to 200 / mm2. delete The method according to claim 1,
Cu-Ni-Si alloy alloy containing 0.005 to 2.5 mass% of at least one of Sn, Zn, Mg, Fe, Ti, Zr, Cr, Al, P, Mn, Co, Cr and Ag in a total amount.

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