JP7042979B2 - Copper alloy plate material and its manufacturing method - Google Patents

Description

The present disclosure relates to a copper alloy plate material and a method for producing the same.

Copper alloy plates used for connectors for electronic devices are generally stamped or stamped. With the recent miniaturization of electronic devices, the shape uniformity of stamped products is required more.

It is known that the shape uniformity of the pressed product is affected by the crystal grain size and the precipitation state of the copper alloy plate material. Attempts have been made to improve the shape uniformity of stamped products by controlling the structure of copper alloy plates.

For example, Patent Document 1 describes a copper alloy thin plate material in which the number density of second phase particles, the plate width in the direction perpendicular to rolling, the plate thickness, the maximum crossbow, the proof stress in the rolling direction, and the like are within predetermined ranges.

Further, in Patent Document 2, Cr: 0.15 to 0.4%, Si: 0.01 to 0.1%, and at least one element selected from the group consisting of Ti and Zr: 0 in total. It contains .005 to 0.15%, the balance is composed of copper and unavoidable impurities, and the average particle size distribution of the precipitate measured by the small-angle X-ray scattering method is 2.0 nm or more and 7.0 nm or less. In addition, copper alloys in which the standardized dispersion of the particle size distribution is in the range of 30 to 40% are described.

Further, Patent Document 3 contains Ni 2.0 to 3.5% and Si 0.5 to 1.0% by mass, the Ni / Si ratio is 3.5 to 4.5, and the balance is Cu. And the copper alloy material consisting of unavoidable impurities, the precipitate evaluated by the small angle scattering method has an average diameter of 2.0 to 3.5 nm and a standardized dispersion of 40% or less in the number distribution of the diameter. A high-strength copper alloy material having a value (R / t) obtained by dividing the minimum bending radius R at which cracking does not occur in the W bending test by the plate thickness t is 1.0 or less is described.

In the copper alloy thin plate material of Patent Document 1, the conductive spring member incorporated in a small mechanical component by controlling the number density of the second phase particles of the Cu—Ni—Co—Si based alloy and the flatness of the plate material. The strength has been increased and the dimensional accuracy during processing has been improved. In Patent Document 1, various material properties are attempted to be controlled in order to improve the dimensional accuracy of the stamped material, that is, the press workability. However, as the pitch of terminals of connectors and lead frames has been narrowed in recent years, the copper alloy thin plate material of Patent Document 1 does not satisfy the high dimensional accuracy required.

In the copper alloy of Patent Document 2, the strength, conductivity, and bending are controlled by controlling the particle size distribution of nanometer-order precipitates in the Cu—Cr—Si alloy based on the particle size distribution measured by the small-angle X-ray scattering method. Improved workability and stress resistance relaxation characteristics. However, Patent Document 2 does not pay attention to the dimensional accuracy of the copper alloy after press working, and it is considered that the copper alloy of Patent Document 2 cannot satisfy the high dimensional accuracy at the time of press working.

In the copper alloy material of Patent Document 3, the strength, conductivity, and bending workability are improved by controlling the particle size distribution of the precipitate of the Cu—Ni—Si based alloy. The particle size distribution of the Cu—Ni—Si based alloy is measured by the small-angle X-ray scattering method. Here, the X-ray small-angle scattering method has a feature that the thicker the copper alloy material as a sample, the smaller the amount of X-ray transmission, and it is difficult to obtain reliable data. In Patent Document 3, a sample having a thickness of 0.2 mm is mechanically and chemically thinned to a thickness of 35 μm, and the copper alloy material is measured with one surface or both surfaces removed. Therefore, in the copper alloy material of Patent Document 3, the precipitation state is not always uniform over the entire plate thickness, which is important for press workability. Further, according to the production method of Patent Document 3, the cooling rate in the solution heat treatment is 1 to 100 ° C./s, and precipitates are generated during cooling and in the subsequent aging heat treatment, so that the particle size of the precipitates can be made uniform. Not.

Patent No. 6573503 Japanese Unexamined Patent Publication No. 2016-21154 Japanese Unexamined Patent Publication No. 2012-162782

An object of the present disclosure is to provide a copper alloy plate material having an excellent balance between strength and conductivity and having excellent press workability and a method for producing the same.

[1] The total content of Co and Ni is 0.10% by mass or more and 5.00% by mass or less, and Si is 0.05% by mass or more and 1.50% by mass or less, and the content ratio of Co and Ni to Si (Co + Ni). ) / Si is 2.50 or more and 6.00 or less, the balance has an alloy composition of Cu and unavoidable impurities, and contains at least one element of Co and Ni obtained by neutron small angle scattering measurement. A copper alloy plate material characterized in that the half-value width of the peak in the particle size distribution curve of Si-based compound particles is 5 nm or less.
[2] The copper alloy plate material according to the above [1], wherein the particle diameter of the peak in the particle size distribution curve of the Si-based compound particles obtained by the small-angle neutron scattering measurement is 1 nm or more and 10 nm or less.
[3] The alloy composition further contains 0.10% by mass or more and 1.00% by mass or less in total of one or more elements selected from the group consisting of Mg, Sn, Zn, P, Cr and Zr. , The copper alloy plate material according to the above [1] or [2].
[4] The copper alloy plate material according to any one of the above [1] to [3], wherein the alloy composition contains Co in an amount of 0.50% by mass or more and 2.50% by mass or less.
[5] The copper alloy plate material according to any one of the above [1] to [4], wherein the alloy composition contains 2.00% by mass or more and 5.00% by mass or less of Ni.
[6] The copper alloy plate material according to any one of the above [1] to [5], wherein the plate thickness of the copper alloy plate material is 50 μm or more and 500 μm or less.
[7] The method for producing a copper alloy plate according to any one of the above [1] to [6], wherein a casting step [step 1], a homogenization treatment step [step 2], and a homogenization treatment step [step 2] are applied to the copper alloy material. The hot rolling step [step 3], face milling step [step 4], cold rolling step [step 5], solution heat treatment step [step 6] and aging heat treatment step [step 7] are performed in this order, and the hot rolling step is performed. In the rolling step [step 3], the rolled material is reverse-rolled in a temperature range where the hot rolling start temperature is 900 ° C. or higher and 1000 ° C. or lower and the hot rolling end temperature is 500 ° C. or higher and 900 ° C. or lower, and the cold rolling step [step 3]. In step 5], the standard deviation of the thickness of the rolled material in the longitudinal direction is within 10 μm, and in the solution heat treatment step [step 6], the first temperature rise rate from 25 ° C to 600 ° C is 80 ° C / s. As described above, the rolled material is heat-treated at a second temperature rising rate of 20 ° C./s or less from 600 ° C. to the maximum reached temperature and a cooling rate of 100 ° C./s or more from the maximum reached temperature to 300 ° C., and the aging heat treatment step [ Step 7] is a method for producing a copper alloy plate, which comprises holding a rolled material within 1 hour or more and 10 hours or less in a temperature range of 300 ° C. or higher and 550 ° C. or lower.
[8] The copper alloy plate material according to the above [7], further comprising an intermediate cold rolling step [step A] between the solution heat treatment step [step 6] and the aging heat treatment step [step 7]. Production method.
[9] The above-mentioned [7] or [8], further comprising a finish cold rolling step [step B1] and a tempering annealing step [step B2] in this order after the aging heat treatment step [step 7]. Manufacturing method of copper alloy plate material.

According to the present disclosure, it is possible to provide a copper alloy plate material having an excellent balance between strength and conductivity and having excellent press workability and a method for producing the same.

FIG. 1 is a perspective view for explaining a method for evaluating press workability. FIG. 2 is a diagram for explaining the ratio of sheared surfaces in the method for evaluating press workability. FIG. 3 is a cross-sectional view for explaining sagging in the method for evaluating press workability.

Hereinafter, a detailed description will be given based on the embodiment.

As a result of diligent research, the present inventors have made small-angle neutron scattering measurements that can measure the state of precipitates over the entire plate thickness of copper alloy plates in view of the demand for higher dimensional accuracy of pressed materials than before. By controlling and homogenizing the particle size distribution of Si-based compound particles over the entire plate thickness of the copper alloy plate material based on the measured values of neutron small-angle scattering measurement, the balance between strength and conductivity is excellent. , It has been found that a copper alloy plate material having excellent press workability can be obtained, and based on such findings, the present disclosure has been completed.

The copper alloy plate material of the embodiment contains Co and Ni in a total amount of 0.10% by mass or more and 5.00% by mass or less, and Si in an amount of 0.05% by mass or more and 1.50% by mass or less, and Co and Ni with respect to Si. Content ratio (Co + Ni) / Si is 2.50 or more and 6.00 or less, the balance has an alloy composition of Cu and unavoidable impurities, and at least one of Co and Ni obtained by neutron small angle scattering measurement. The half-price width of the peak in the particle size distribution curve of the Si-based compound particles containing the element is 5 nm or less.

First, the alloy composition of the copper alloy plate will be described.

The copper alloy plate material of the above embodiment contains Co and Ni in a total amount of 0.10% by mass or more and 5.00% by mass or less, and Si in an amount of 0.05% by mass or more and 1.50% by mass or less. It has an alloy composition in which the Ni content ratio (Co + Ni) / Si is 2.50 or more and 6.00 or less, and the balance is Cu and unavoidable impurities.

<Co and Ni total 0.10% by mass or more and 5.00% by mass or less>
Co (cobalt) and Ni (nickel) are elements that increase the strength of copper alloy plates. When the total of Co and Ni is 0.10% by mass or more, the strength of the copper alloy plate can be increased. Further, when the total of Co and Ni is 5.00% by mass or less, the decrease in the conductivity of the copper alloy plate can be suppressed and the generation of coarse crystals in the ingot is suppressed, which will be described later. After the solution heat treatment step [Step 6], the phenomenon that the coarse crystallization is generated by the remaining unsolidified crystallization and the coarse crystallization induces cracks during press working is suppressed, and the copper alloy is suppressed. The press workability of the plate material can be improved. Therefore, it contains Co and Ni in a total amount of 0.10% by mass or more and 5.00% by mass or less. From the viewpoint of increasing the strength of the copper alloy plate material, the total of Co and Ni is preferably 0.80% by mass or more, more preferably 1.40% by mass or more. Further, from the viewpoint of suppressing the decrease in the conductivity of the copper alloy plate material and improving the press workability, the total of Co and Ni is preferably 4.00% by mass or less, more preferably 3.50% by mass or less. ..

Further, in addition to the above-mentioned effects of Co and Ni, Co has an effect of promoting precipitation of Si-based compound particles in the aging heat treatment step [step 7] and increasing the conductivity of the copper alloy plate material as compared with Ni. .. Therefore, the alloy composition contains Co in an amount of preferably 0.50% by mass or more, more preferably 0.80% by mass or more, preferably 2.50% by mass or less, and more preferably 2.00% by mass or less. ..

Further, in addition to the above-mentioned effects of Co and Ni, Ni can have a higher solid solubility in copper than Co in the solution heat treatment step [step 6], and is therefore effective in increasing the strength of the copper alloy plate material by aging precipitation. It is a target. Therefore, the alloy composition contains Ni in an amount of preferably 2.00% by mass or more, more preferably 3.60% by mass or more, still more preferably 3.70% by mass or more, and preferably 5.00% by mass or less. It is preferably contained in an amount of 4.80% by mass or less.

Further, in the above range, the larger the content of both Co and Ni, the more effective the strength of the copper alloy plate material is. From the viewpoint of increasing the strength of the copper alloy plate material, it is preferable to increase the concentration of Ni alone as compared with increasing the concentration of Co alone. The reason is that Ni can lower the heat treatment temperature in the solution heat treatment step [step 6], which is important for increasing the amount of precipitation strengthening of Si-based compound particles, as compared with Co.

<Si: 0.05% by mass or more and 1.50% by mass or less>
Si (silicon) is an element that forms Si-based compound particles with Ni and Co and enhances the strength of the copper alloy plate material. When Si is 0.05% by mass or more, the strength of the copper alloy plate can be increased. Further, when Si is 1.50% by mass or less, the decrease in the conductivity of the copper alloy plate can be suppressed, and the generation of coarse crystallization in the ingot is suppressed. Therefore, the solution heat treatment step [ Step 6] The phenomenon that the coarse crystallized material induces cracks during press working, which is generated by the coarse crystallized product remaining in an unsolid solution state, is suppressed, and the press workability of the copper alloy plate material is improved. Can be improved. Therefore, Si is contained in an amount of 0.05% by mass or more and 1.50% by mass or less. From the viewpoint of increasing the strength of the copper alloy plate material, Si is preferably 0.07% by mass or more, more preferably 0.10% by mass or more. Further, Si is preferably 1.25% by mass or less, more preferably 1.00% by mass or less, from the viewpoint of suppressing a decrease in conductivity of the copper alloy plate material and improving press workability.

<(Co + Ni) / Si: 2.50 or more and 6.00 or less>
The content ratio of Co and Ni to Si (Co + Ni) / Si is 2.50 or more and 6.00 or less. When (Co + Ni) / Si is 2.50 or more, the Si content is not excessive with respect to the total amount of Co and Ni, so that the residual amount of Si in the matrix increases during the aging heat treatment step [Step 7]. The decrease in conductivity of the copper alloy plate material caused by this is suppressed. Further, when (Co + Ni) / Si is 6.00 or less, the total amount of Co and Ni is not excessive with respect to the content of Si, so that the decrease in the conductivity of the copper alloy plate material is suppressed. From the viewpoint of improving the conductivity of the copper alloy plate material, (Co + Ni) / Si is preferably 3.00 or more, more preferably 3.30 or more, preferably 5.00 or less, and more preferably 4.70. It is as follows.

<Auxiliary component of copper alloy plate: 0.10% by mass or more and 1.00% by mass or less>
The alloy composition of the copper alloy plate further contains 0.10% by mass or more and 1.00% by mass or less in total of one or more elements selected from the group consisting of Mg, Sn, Zn, P, Cr and Zr. be able to. That is, in the copper alloy plate material, in addition to the above basic components, as an optional component, one or more components selected from the group consisting of Mg, Sn, Zn, P, Cr and Zr are summed up. It can be contained in an amount of 0.10% by mass or more and 1.00% by mass or less. When the content of the auxiliary component is 0.10% by mass or more, the strength of the copper alloy plate material can be improved. Further, when the content of the auxiliary component is 1.00% by mass or less, the decrease in the conductivity of the copper alloy plate can be suppressed and the press workability can be improved.

Each sub-ingredient will be described below.

<Mg: 0.10% by mass or more and 0.30% by mass or less>
When the content of Mg (magnesium) is 0.10% by mass or more, the stress relaxation resistance of the copper alloy plate can be improved. When the Mg content is 0.30% by mass or less, it is possible to suppress a decrease in the conductivity of the copper alloy plate material. Therefore, the Mg content is preferably in the range of 0.10% by mass or more and 0.30% by mass or less.

<Sn: 0.10% by mass or more and 0.30% by mass or less>
When the Sn (tin) content is 0.10% by mass or more, the stress relaxation resistance of the copper alloy plate can be improved. When the Sn content is 0.30% by mass or less, it is possible to suppress a decrease in the conductivity of the copper alloy plate material. Therefore, the Sn content is preferably in the range of 0.10% by mass or more and 0.30% by mass or less.

<Zn: 0.10% by mass or more and 0.50% by mass or less>
When the Zn (zinc) content is 0.10% by mass or more, the adhesion and migration characteristics of Sn plating and solder plating can be improved. When the Zn content is 0.50% by mass or less, it is possible to suppress a decrease in the conductivity of the copper alloy plate material. Therefore, the Zn content is preferably in the range of 0.10% by mass or more and 0.50% by mass or less.

<P: 0.10% by mass or more and 0.30% by mass or less>
When the content of P (phosphorus) is 0.10% by mass or more, the precipitation of Si-based compound particles on the grain boundaries can be suppressed and the strength of the copper alloy plate can be increased. When the content of P is 0.30% by mass or less, the decrease in the conductivity of the copper alloy plate can be suppressed. Therefore, the content of P is preferably in the range of 0.10% by mass or more and 0.30% by mass or less.

<Cr: 0.10% by mass or more and 0.30% by mass or less>
When the Cr (chromium) content is 0.10% by mass or more, coarsening of crystal grains in the solution heat treatment step [step 6] can be suppressed. When the Cr content is 0.30% by mass or less, the formation of coarse Cr-containing crystallization in the casting step [Step 1] is suppressed, so that the coarse Cr-containing crystallization is pressed. It can be suppressed from becoming the starting point of cracks. Therefore, the Cr content is preferably in the range of 0.10% by mass or more and 0.30% by mass or less.

<Zr: 0.10% by mass or more and 0.20% by mass or less>
When the content of Zr (zirconium) is 0.10% by mass or more, coarsening of crystal grains in the solution heat treatment step [step 6] can be suppressed. When the Zr content is 0.20% by mass or less, the formation of coarse Zr-containing crystallization in the casting step [Step 1] is suppressed, so that the coarse Zr-containing crystallization is pressed. It can be suppressed from becoming the starting point of cracks. Therefore, the Zr content is preferably in the range of 0.10% by mass or more and 0.20% by mass or less.

<Remaining: Cu and unavoidable impurities>
The rest other than the components mentioned above are Cu (copper) and unavoidable impurities. The unavoidable impurities are unavoidably mixed in the manufacturing process, are impurities at a content level that can be unavoidably contained, and are allowable impurity components because they do not affect the characteristics of the copper alloy plate material. The smaller the content of unavoidable impurities, the more preferable. Examples of unavoidable impurities include elements such as Bi (bismuth), Se (selenium), As (arsenic), and Ag (silver). The upper limit of the content of unavoidable impurities is preferably 0.03% by mass for each of the above elements, and preferably 0.10% by mass for the total amount of the above elements.

Next, the plate thickness of the copper alloy plate material will be described.

In the method for producing a copper alloy plate material of the embodiment described later, the thicker the plate, the slower the first temperature rise rate and the cooling rate in the solution heat treatment step [step 6], and the second phase compound remaining after the heat treatment. Since the number of certain Si-based compound particles increases, the press workability of the copper alloy plate tends to decrease. From the viewpoint of suppressing deterioration of press workability, the plate thickness of the copper alloy plate material is preferably 500 μm or less, more preferably 400 μm or less, still more preferably 300 μm or less. Further, in order to satisfy strength such as rigidity, the plate thickness of the copper alloy plate material is preferably 50 μm or more. Copper alloy plate materials whose plate thickness is within the above numerical range are suitably used as electronic contact components such as connectors and lead frames, which tend to be thinner due to higher mounting densities of electronic components and the like.

Next, the small-angle neutron scattering measurement for the copper alloy plate will be described.

The copper alloy plate is measured by the small-angle neutron scattering method. First, the small-angle scattering method irradiates a sample, which is a measurement object, with neutrons and X-rays, and analyzes the neutrons and X-rays scattered at a small angle of 10 degrees or less to obtain average information on the microstructure in the sample. It is a method to acquire. In the small-angle scattering method, information on the average size and orientation of the second phase contained in the sample can be obtained.

In the embodiment, the state of the precipitate is evaluated over the entire plate thickness of the copper alloy plate material in view of the demand for higher dimensional accuracy of the pressed material than before. From this point of view, if the radiation source is capable of transmitting a copper alloy plate material having a thickness of, for example, 50 μm or more, highly accurate measurement can be performed over the entire plate thickness of the copper alloy plate material. Therefore, in the embodiment, the small-angle neutron scattering method is used.

The small-angle neutron scattering method provides average information for thicker samples than the small-angle X-ray scattering method. For example, in the case of X-rays from a Cu radiation source, the incident energy of the X-rays is 8.04 keV. When small-angle scattering measurement of a copper alloy plate is carried out using this X-ray, it is necessary to process the copper alloy plate to a thickness of 20 μm or less in order to secure sufficient X-ray transmittance. The information of the sample obtained by thinly processing the copper alloy plate is only a part (20 μm or less) of the copper alloy plate and does not reflect the whole of the copper alloy plate. That is, the small-angle X-ray scattering measurement is insufficient for the analysis of the above-mentioned copper alloy plate material. Therefore, in the embodiment, the small-angle neutron scattering measurement is performed using neutrons capable of sufficiently transmitting a plate thickness of 1000 μm or more.

The small-angle neutron scattering measurement uses the Ibaraki Prefectural Material Structure Analyzer (iMATERIA) installed in BL20 in the J-PARC (Japan Protocol Accelerator Research Complex), a high-intensity proton accelerator facility. A plurality of copper alloy plates having a plate thickness of 40 μm or more and 120 μm or less are stacked, and a copper alloy plate having a total thickness of about 2 mm is measured. The beam diameter of neutrons is 10 mm. The measurement time is 20 minutes. The analysis of converting the small-angle scattering profile obtained by the small-angle neutron scattering measurement to the particle size distribution is performed by Irena, a software developed by Jan Ilavsky of Argonne National Laboratory. In the analysis, fitting is performed using a spherical model, and the particle size distribution of the second phase is obtained.

Next, the half-value width of the peak in the particle size distribution curve of the Si-based compound particles obtained by the small-angle neutron scattering measurement of the copper alloy plate will be described.

The half-value width of the peak in the particle size distribution curve of the Si-based compound particles containing at least one of Co and Ni elements obtained by the small-angle neutron scattering measurement of the copper alloy plate is 5 nm or less. When the Si-based compound particles, which are the second phase compounds measured by the small-angle neutron scattering method, are 5 nm or less, the uniformity of the particle size distribution of the Si-based compounds is improved, so that cracks in the press punching material are generated and propagated. Is homogenized. When the behavior of cracks becomes uniform, the shape of the stamped fracture surface itself becomes uniform, and the internal strain of the stamped material is uniformly released, so that the dimensional accuracy of the stamped material is improved.

When the half width of the peak in the particle size distribution curve of the Si-based compound particles obtained by the small-angle neutron scattering measurement is 5 nm or less, the dimensional accuracy of the pressed material required for electronic contact parts such as connectors and lead frames can be obtained. The smaller the half width of the peak, the better the dimensional accuracy of the stamped material.

Next, the particle size of the peak in the particle size distribution curve of the Si-based compound particles obtained by the small-angle neutron scattering measurement of the copper alloy plate will be described.

The particle size of the peak in the particle size distribution curve of the Si-based compound particles obtained by the small-angle neutron scattering measurement of the copper alloy plate is preferably 1 nm or more and 10 nm or less. When the particle size of the peak is 1 nm or more, the Si-based compound particles grow into a matching precipitate that causes precipitation strengthening, so that the strength of the copper alloy plate can be further increased. When the particle size of the peak is 10 nm or less, the decrease in the strength of the copper alloy plate can be further suppressed. When the particle size of the peak is 3 nm or more, the strength of the copper alloy plate material is further improved. When the particle size of the peak is 8 nm or less, the decrease in the strength of the copper alloy plate material is further suppressed.

Next, the tensile strength of the copper alloy plate material will be described.

Copper alloy plates have high tensile strength. The tensile strength of the copper alloy plate material can be measured by performing a tensile test based on JIS Z 2241: 2011 using a JIS 13B test piece. The tensile strength of the copper alloy plate is the tensile strength in the direction parallel to rolling. The tensile strength of the copper alloy plate is 500 MPa or more, preferably 600 MPa or more, more preferably 700 MPa or more, still more preferably 800 MPa or more.

Next, the conductivity of the copper alloy plate material will be described.

The copper alloy plate has high conductivity. The conductivity of the copper alloy plate material can be calculated by measuring the specific resistance by the 4-terminal method in a constant temperature bath maintained at 20 ° C. (± 0.5 ° C.) with the distance between terminals being 100 mm. The conductivity of the copper alloy plate is 30% IACS or more, preferably 40% IACS or more, more preferably 50% IACS or more, still more preferably 60% IACS or more.

Next, the press workability of the copper alloy plate material will be described.

In the press fracture surface of the copper alloy plate material after press punching, it is preferable that the difference in the ratio of the shear surface to the fracture surface is small and the difference in the size of sagging is small. Copper alloy plates with a small difference in the ratio of sheared surfaces and a small difference in the size of sagging have excellent dimensional accuracy after press working.

The copper alloy plate material described above is suitable for electrical contact parts such as connectors and lead frames for electrical and electronic devices, which require a balance between strength and conductivity and high dimensional accuracy after press working. In particular, it is suitable for an electric contact component or the like in which a press punching process at a fine pitch is incorporated in the manufacturing process.

Next, a method for manufacturing the copper alloy plate material of the embodiment will be described.

The method for producing the copper alloy plate material of the embodiment is as follows: casting step [step 1], homogenization treatment step [step 2], hot rolling step [step 3], face milling step [step 4], and cooling on the copper alloy material. The hot rolling step [step 5], the solution heat treatment step [step 6], and the aging heat treatment step [step 7] are performed in this order. In the hot rolling step [step 3], the hot rolling start temperature is 900 ° C. or higher and 1000 ° C. Hereinafter, in the cold rolling step [step 5], the rolled material is reverse-rolled in a temperature range where the hot rolling end temperature is 500 ° C. or higher and 900 ° C. or lower, and the standard deviation of the rolled material in the longitudinal direction is within 10 μm. In the solution heat treatment step [Step 6], the first temperature rise rate from 25 ° C. to 600 ° C. is 80 ° C./s or more, and the second temperature rise rate from 600 ° C. to the maximum reached temperature is 20 ° C./s or less. In the aging heat treatment step [Step 7], the rolled material is heat-treated at a cooling rate of 100 ° C./s or more from the maximum reached temperature to 300 ° C. Hold the rolled material in.

In the casting step [step 1], a copper alloy ingot having a predetermined shape is obtained by melting the alloy component and casting. For example, melting is performed in the atmosphere using a high frequency melting furnace. The types of alloy components, casting conditions, etc. are set as appropriate.

In the homogenization treatment step [step 2], the copper alloy ingot obtained in the casting step [step 1] is subjected to a homogenization treatment under predetermined heating conditions (for example, at 1000 ° C. or lower for 1 hour). The homogenization treatment step [step 2] is performed, for example, in the atmosphere.

In the hot rolling step [step 3], the rolled material is reverse-rolled in a temperature range in which the hot rolling start temperature is 900 ° C. or higher and 1000 ° C. or lower and the hot rolling end temperature is 500 ° C. or higher and 900 ° C. or lower. By performing reverse rolling, the deformed structure of the rolled material becomes uniform, and the precipitation state of the size of the Si-based compound particles becomes uniform through the solution heat treatment step [step 6] and the aging heat treatment step [step 7]. be.

The hot rolling start temperature is 900 ° C. or higher and 1000 ° C. or lower. When the hot rolling start temperature is less than 900 ° C., the solid solubility is low, the residual amount of the Si-based compound increases in the solution heat treatment step [step 6], the strength of the copper alloy plate material decreases, and the stamping process is performed. The dimensional accuracy of the material is reduced. When the hot rolling start temperature is more than 1000 ° C., it is higher than the melting point of the copper alloy, and it becomes difficult to maintain the shape of the rolled material. From the viewpoint of improving the strength and press workability of the copper alloy plate material, the hot rolling start temperature is preferably 950 ° C. or higher, more preferably 990 ° C. or higher.

The hot rolling end temperature is 500 ° C. or higher and 900 ° C. or lower. When the hot rolling end temperature is less than 500 ° C., precipitation of the Si-based compound proceeds, the residual amount of the Si-based compound increases during the solution heat treatment step [step 6], and the strength of the copper alloy plate material decreases. , The dimensional accuracy of the stamped material is reduced. Further, since the hot rolling start temperature is 900 ° C. or higher and 1000 ° C. or lower, when the hot rolling end temperature is 900 ° C. or lower, workability such as temperature control in the hot rolling step [step 3] is easy. .. From the viewpoint of improving the strength and press workability of the copper alloy plate material, the hot rolling end temperature is preferably 600 ° C. or higher, more preferably 700 ° C. or higher.

In the face-cutting step [step 4], a face-cutting of a predetermined thickness (for example, 2.5 mm or more and 5.0 mm or less) is performed from the surface of the hot-rolled plate to remove the oxide film.

In the cold rolling step [step 5], the standard deviation of the thickness of the rolled material obtained by cold rolling in the longitudinal direction is within 10 μm. In the cold rolling step [step 5], the plate thickness of the rolled material is made uniform in order to make the temperature change of the entire rolled material during the temperature rise and cooling in the solution heat treatment step [step 6] uniform.

Conventionally, in general, the accuracy of the plate thickness in the cold rolling performed in a relatively upper process such as this process is lower than that in the cold rolling of the finish which determines the plate thickness performed in the lower process, and the plate thickness is reduced. There is a large variation in. If the plate thickness of the rolled material in the cold rolling step [step 5] varies widely as in the conventional cold rolling, the temperature change of the entire rolled material in the solution heat treatment step [step 6] varies. Increase. Therefore, the standard deviation in the longitudinal direction of the plate thickness of the rolled material in the cold rolling step [step 5] is set to 10 μm or less. If the standard deviation of the plate thickness of the rolled material is larger than 10 μm, the variation in the plate thickness increases, and the press workability of the copper alloy plate material deteriorates.

In the solution heat treatment step [step 6], the first temperature rise rate from 25 ° C. to 600 ° C. is 80 ° C./s or more, and the second temperature rise rate from 600 ° C. to the maximum reached temperature is 20 ° C./s or less, which is the maximum. The rolled material is heat-treated at a cooling rate of 100 ° C./s or higher from the reached temperature to 300 ° C. The rolled material in the solution heat treatment step [step 6] undergoes a two-step temperature rise in order to sufficiently dissolve the crystallization and precipitates generated up to the previous step.

In the first step, the first temperature rising rate from 25 ° C. (room temperature) to 600 ° C. is set to 80 ° C./s or higher to suppress precipitation during temperature rise. If the first temperature rising rate is less than 80 ° C./s, precipitation proceeds and press workability is deteriorated.

Next, in the second step, the second temperature rising rate from 600 ° C. to the maximum reached temperature is set to 20 ° C./s or less to promote solid solution. If the second temperature rising rate is more than 20 ° C./s, the solid solution is insufficient and the press workability is deteriorated. In order to promote solid solution, it is preferable to hold the product in a temperature range of 750 ° C. or higher and 1000 ° C. or lower for 10 seconds or more and 180 seconds or less.

Next, cooling is performed at a cooling rate of 100 ° C./s or higher from the maximum temperature reached to 300 ° C. If the cooling rate is less than 100 ° C./s, the amount of precipitates increases during cooling, and the particle size difference from the precipitates precipitated in the aging heat treatment step [step 7] is generated, so that the dimensional accuracy of the stamped material is high. descend. On the other hand, when rapid cooling at a cooling rate of more than 150 ° C./s is performed from a temperature of 750 ° C. or higher and 1000 ° C. or lower, high thermal stress is generated, and defects due to plastic deformation are likely to occur in the rolled material. Therefore, the upper limit of the cooling rate is preferably 150 ° C./s.

In the aging heat treatment step [step 7], the rolled material is held within 1 hour or more and 10 hours or less in a temperature range of 300 ° C. or higher and 550 ° C. or lower. When the holding temperature of the rolled material is less than 300 ° C. and more than 550 ° C., the strength of the copper alloy plate material decreases. Therefore, the holding temperature of the rolled material is preferably 450 ° C. or higher, and preferably 520 ° C. or lower.

As described above, when the conditions of the hot rolling step [step 3], the cold rolling step [step 5], the solution heat treatment step [step 6], and the aging heat treatment step [step 7] are set as described above, the copper alloy is formed. The half-value width of the peak in the particle size distribution curve of the Si-based compound particles obtained by the neutron small-angle scattering measurement of the plate material is 5 nm or less.

Further, the method for producing a copper alloy plate material of the above embodiment may further include an intermediate cold rolling step [step A] between the solution heat treatment step [step 6] and the aging heat treatment step [step 7]. preferable. The intermediate cold rolling step [step A] performed before the aging heat treatment step [step 7] further increases the strength of the copper alloy plate material.

Further, the method for producing a copper alloy plate material of the above embodiment may further include a finish cold rolling step [step B1] and a tempering annealing step [step B2] in this order after the aging heat treatment step [step 7]. preferable. The finish cold rolling step [step B1] performed after the aging heat treatment step [step 7] further increases the strength of the copper alloy plate material. Further, when the intermediate cold rolling step [step A] and the finishing cold rolling step [step B1] are performed, the strength of the copper alloy plate material is further increased. When the finish cold rolling step [process B1] is performed, the temper shrinking step [process B2] is performed after the finish cold rolling step [process B1] in order to reduce the residual stress.

In the finish cold rolling process [process B1], the processing ratio can be appropriately selected according to the desired strength. From the viewpoint of improving the strength and stress relaxation resistance of the copper alloy plate material, the processing rate of the finish cold rolling step [step B1] is preferably 5% or more and 60% or less. When the processing rate is 5% or more, the effect of improving the strength of the copper alloy plate material is great. When the processing rate is 60% or less, the residual stress decreases and the stress relaxation resistance of the copper alloy plate material increases.

In the temper annealing step [step B2], the heating temperature and the heating time can be appropriately selected according to the desired strength and stress relaxation resistance. From the viewpoint of improving the strength and stress relaxation resistance of the copper alloy plate, the heating temperature is preferably 300 ° C. or higher and 600 ° C. or lower, and the heating time is preferably 10 seconds or longer and 1 hour or shorter.

According to the embodiment described above, hot rolling is performed based on the measured value of the neutron small angle scattering measurement using the neutron small angle scattering measurement that can measure the state of the precipitate over the entire plate thickness of the copper alloy plate with high accuracy. While setting the conditions of the step [step 3], the cold rolling step [step 5], the solution heat treatment step [step 6], and the aging heat treatment step [step 7] within a predetermined range, the entire plate thickness of the copper alloy plate material is covered. By controlling the particle size distribution of the Si-based compound particles within a predetermined range, a copper alloy plate material having an excellent balance between strength and conductivity and excellent press workability can be obtained.

Although the embodiments have been described above, the present invention is not limited to the above embodiments, but includes all aspects included in the concept of the present disclosure and the scope of claims, and various modifications are made within the scope of the present disclosure. be able to.

Next, Examples and Comparative Examples will be described, but the present invention is not limited to these Examples.

(Examples 1 to 22 and Comparative Examples 1 to 11)
Each alloy component was melted in the atmosphere by a high-frequency melting furnace and cast by a mold to obtain a copper alloy ingot having the alloy composition shown in Table 1. Next, a homogenization heat treatment step was performed at 1000 ° C. for 1 hour in the air. Next, in the hot rolling step [step 3], reverse rolling is performed under the conditions of the hot rolling start temperature and the hot rolling end temperature shown in Table 2, and then in the face cutting step, the surface of the hot rolled material is surfaced. Was surface-cut to remove the oxide film. Next, in the cold rolling step [step 5], cold rolling was performed, and the standard deviation in the longitudinal direction of the plate thickness of the rolled material was set to the value shown in Table 2. Next, in the solution heat treatment step [step 6], as shown in Table 2, the first temperature rise rate from 25 ° C. to 600 ° C., the second temperature rise rate from 600 ° C. to the maximum temperature reached, and the maximum temperature reached. The rolled material was heat treated at a cooling rate from the highest temperature reached to 300 ° C. Next, in the aging heat treatment step [step 7], the rolled material was held at the heating temperature and heating time shown in Table 2. In this way, a copper alloy plate material was manufactured.

[Measurement and evaluation]
The copper alloy plates obtained in the above Examples and Comparative Examples were measured and evaluated as follows. The results are shown in Tables 3-5.

[1] Reliability of the small-angle neutron scattering method and the small-angle X-ray scattering method The transmittance of neutrons for small-angle neutron scattering measurement and the transmission of X-rays for small-angle X-ray scattering measurement in the copper alloy plate material obtained in Example 11 The results of the rate are shown in Table 3. The wavelength of the neutron was 0.7 nm, and the X-ray was CuKα (8.04 keV). In the case of neutrons, even a copper alloy plate having a plate thickness of 1000 μm sufficiently transmitted neutrons. Therefore, it was suggested that the small-angle neutron scattering method is highly reliable. On the other hand, in the case of X-rays, the transmittance of X-rays was very small in the copper alloy plate material having a plate thickness of 50 μm or more. Therefore, it was suggested that the X-ray small-angle scattering method can be used for copper alloy plates with a plate thickness of 30 μm or less, but has low reliability for thicker copper alloy plates. Furthermore, it was suggested that it is difficult to use the small-angle X-ray scattering method for copper alloy plates having a plate thickness of 100 μm or more because they hardly transmit X-rays. The reliability of each small-angle scattering method was ranked as follows.

◯: Transmittance is 25% or more Δ: Transmittance is 5% or more and less than 25% ×: Transmittance is less than 5%

[2] Small-angle neutron scattering measurement For the copper alloy plates obtained in the above examples and comparative examples, Ibaraki Prefecture materials installed in BL20 in the high-intensity proton accelerator facility J-PARC (Japan Protocol Accelerator Research Complex). Small-angle neutron scattering measurements were performed using a structural analyzer (iMATERIA). A plurality of copper alloy plates having a plate thickness of 120 μm were stacked, and a copper alloy plate having a total thickness of about 2 mm was measured. The beam diameter of the neutron was 10 mm. The measurement time was 20 minutes. The analysis of converting the small-angle scattering profile obtained by the small-angle neutron scattering measurement to the particle size distribution was performed with Irena, a software developed by Jan Ilavsky of Argonne National Laboratory. In the analysis, fitting was performed using a spherical model to determine the particle size distribution of the second phase. Then, the half width and the particle diameter of the peak in the particle size distribution curve of the Si-based compound particles were obtained.

[3] Tensile strength Tensile tests were conducted on the copper alloy plates obtained in the above Examples and Comparative Examples based on JIS Z 2241: 2011 using three JIS 13B test pieces (n = 3). The tensile strength was calculated by averaging the three measured values. The tensile strength of the copper alloy plate was the tensile strength in the direction parallel to rolling. If it is less than 500 MPa, the tensile strength is poor.

[4] Conductivity With respect to the copper alloy plates obtained in the above Examples and Comparative Examples, the 4-terminal method was performed in a constant temperature bath kept at 20 ° C (± 0.5 ° C) with a distance between terminals of 100 mm. The conductivity was calculated by measuring the specific resistance. If it is less than 30% IACS, the conductivity is poor.

[5] Press workability The following press workability was evaluated for the copper alloy plate materials obtained in the above Examples and Comparative Examples. First, as shown in FIG. 1, the clearance d along the rolling parallel direction is 5% of the plate thickness of the copper alloy plate material 1, the length in the rolling vertical direction is 20 mm, and the copper alloy plate material 1 is press-punched without lubrication. did. In the press fracture surface 2 of the copper alloy plate 1 after press punching, the ratio of the shear surface to the fracture surface and the size of sagging were measured, respectively.

The ratio (λ) of the sheared surface 3 on the pressed fracture surface 2 was calculated from the following equation (1). In the formula (1), as shown in FIG. 2, as shown in FIG. ₂ , the length of the sheared surface 3 in the plate thickness direction and the plate thickness direction of the fracture surface 4 at _a certain position in the vertical direction of rolling, respectively. Represents the length. Then, λ _max having the longest length a ₁ in the plate thickness direction of the sheared surface 3 and λ _min having the shortest length a ₁ in the plate thickness direction of the sheared surface 3 were measured, and the difference in λ (Δλ = λ) was measured. _max −λ _min ) was calculated. This measurement was performed on three copper alloy plates. Then, the average value (Δλ _av ) of the three Δλs was taken as the ratio of the shear planes.

λ = 100 × a ₁ / (a ₁ + a ₂ ) ・ ・ ・ Equation (1)

As shown in FIG. 3, the size of the sagging b was measured from the cross section of the press fracture surface 2 in the rolling parallel direction. Specifically, the sagging b was measured at each of the four cross sections at intervals of 4 mm along the vertical direction of rolling, and the difference (Δb) between the maximum and the minimum of the four sagging b was calculated. This measurement was performed on three copper alloy plates. Then, the average value ( _{Δba v} ) of the three Δb was taken as the size of the sagging.

The press workability was ranked as follows. In the × rank, the press workability is poor.

⊚: Δλ _av is 10% or less and Δba _av is 5 μm or less ◯: Δλ _av is 10% or less or Δba _av is 5 μm or less ×: Δλ _av is more than 10% and Δba _av is more than 5 μm

(Examples 23 to 25)
A copper alloy plate was manufactured in the same manner as in Example 2 except that the plate thickness was changed, and the copper alloy plate was measured and evaluated. The results are shown in Tables 6-9.

As shown in Tables 1 to 9, in Examples 1 to 25, since the half width of the peak of the alloy composition, the plate thickness, and the particle size distribution curve was within the predetermined range, the tensile strength, the conductivity, and the press workability were all within the predetermined ranges. Was also good. In particular, in Examples 2 to 4, the hot rolling start temperature and hot rolling end temperature of the hot rolling step [step 3], the first heating rate and the second heating rate of the solution heat treatment step [step 6] Since the cooling rate was within a suitable range and the half-value width of the peak in the particle size distribution curve of the Si-based compound particles as the second phase particles was small, the press workability was excellent. Further, in Example 4, Co, Co + Ni and Co + Ni / Si were preferable, and the balance between strength and conductivity was particularly good. In Example 8, the aging temperature in the aging heat treatment step [7] was slightly higher than the preferable range, the particle size of the peak was large, and the strength was slightly low. In Example 9, since the particle size of the peak was appropriate, the strength was improved as compared with Example 8. In Example 10, the aging temperature was more preferable than that in Example 9, and the strength was improved. In Example 22, the Ni concentration was more preferable and the strength was higher than in Examples 20 and 21.

Regarding the influence of the plate thickness, in the small-angle neutron scattering measurements of Examples 2 and 23 to 25, the half width and the particle diameter of the peak of the particle size distribution curve were the same. Since the X-ray transmission rate is low in the X-ray small-angle scattering measurement of Example 2, the half-value width and the particle size of the peak are the X-ray small-angle scattering measurement of Example 23 and the small-angle neutrons of Examples 2 and 23 to 25. It was very different from the scattering measurement. Further, in the X-ray small-angle scattering measurement of Examples 24 to 25, the measurement was impossible because the X-ray was hardly transmitted. Therefore, in the measurement of the particle size distribution of the Si-based compound in the copper alloy plate produced in the example, it was found that the small-angle neutron scattering method is good and the small-angle X-ray scattering method cannot be adopted.

On the other hand, in Comparative Examples 1 to 11, at least one of tensile strength, conductivity, and press workability was poor. In Comparative Example 1, the contents of Co and Ni were high, a large amount of coarse crystallization was generated, and the press workability was poor. In Comparative Example 2, the contents of Co and Ni were low, the content of Si was low, and the strength was poor. In Comparative Example 3, (Co + Ni) / Si was high and the strength was poor. In Comparative Example 4, (Co + Ni) / Si was low and the conductivity was poor. In Comparative Example 5, the hot rolling start temperature in the hot rolling step [step 3] was low, and many coarse Si-based compound particles were present at the time when the hot rolling was completed, and Si was present in the solution heat treatment step [step 6]. The system compound could not be completely dissolved, the half-price width of the above peak on the particle size distribution curve became large, and the press workability was poor. In Comparative Example 6, the hot rolling end temperature of the hot rolling step [step 3] was low, and when the hot rolling was completed, the precipitation of Si-based compound particles proceeded, and Si-based during the solution heat treatment step [step 6]. The compound could not be completely dissolved, the half-price width of the peak of the particle size distribution curve became large, and the press workability was poor. In Comparative Example 7, the first heating rate in the solution heat treatment step [step 6] was slow, the half width of the peak of the particle size distribution curve was large, and the press workability was poor. In Comparative Example 8, the solution heat treatment temperature was relatively low, the Si-based compound particles could not be sufficiently solid-dissolved, the amount of remaining Si-based compound particles increased, the half-value width of the peak of the particle size distribution curve became large, and the press was performed. The workability was poor. In Comparative Example 9, the second temperature rise rate in the solution heat treatment step [step 6] was high, solid dissolution was inhibited, the half width of the peak of the particle size distribution curve was large, and the press workability was poor. In Comparative Example 10, the standard deviation of the plate thickness of the rolled material in the cold rolling step [step 5] was large, the half width of the peak of the particle size distribution curve was large, and the press workability was poor. In Comparative Example 11, the first heating rate and the cooling rate in the solution heat treatment step [Step 6] were slow, the half width of the peak of the particle size distribution curve was large, and the press workability was poor.

1 Copper alloy plate 2 Press fracture surface 3 Shear surface 4 Fracture surface a ₁ Shear surface length a ₂ Fracture surface length b Dripping d Clearance

Claims (9)

The total content of Co and Ni is 0.10% by mass or more and 5.00% by mass or less, and Si is 0.05% by mass or more and 1.50% by mass or less, and the content ratio of Co and Ni to Si (Co + Ni) / Si. Has an alloy composition of 2.50 or more and 6.00 or less, and the balance is Cu and unavoidable impurities.
The half-value width of the peak in the particle size distribution curve of Si-based compound particles containing at least one of Co and Ni elements obtained by small-angle neutron scattering measurement is 5 nm or less .
A copper alloy plate material characterized in that the particle size of the peak in the particle size distribution curve of the Si-based compound particles obtained by the small-angle neutron scattering measurement is 1 nm or more and 14 nm or less . The copper alloy plate material according to claim 1, wherein the peak particle diameter in the particle size distribution curve of the Si-based compound particles obtained by the small-angle neutron scattering measurement is 1 nm or more and 10 nm or less. The alloy composition further comprises 0.10% by mass or more and 1.00% by mass or less in total of one or more elements selected from the group consisting of Mg, Sn, Zn, P, Cr and Zr. The copper alloy plate material according to 1 or 2. The copper alloy plate material according to any one of claims 1 to 3, wherein the alloy composition contains Co in an amount of 0.50% by mass or more and 2.50% by mass or less. The copper alloy plate material according to any one of claims 1 to 4, wherein the alloy composition contains Ni in an amount of 2.00% by mass or more and 5.00% by mass or less. The copper alloy plate material according to any one of claims 1 to 5, wherein the plate thickness of the copper alloy plate material is 50 μm or more and 500 μm or less. The method for manufacturing a copper alloy plate according to any one of claims 1 to 6.
Casting process [process 1], homogenization process [process 2], hot rolling process [process 3], face milling process [process 4], cold rolling process [process 5], solution heat treatment for copper alloy material Step [step 6] and aging heat treatment step [step 7] are performed in this order.
In the hot rolling step [step 3], the rolled material is reverse-rolled in a temperature range in which the hot rolling start temperature is 900 ° C. or higher and 1000 ° C. or lower and the hot rolling end temperature is 500 ° C. or higher and 900 ° C. or lower.
In the cold rolling step [step 5], the standard deviation of the thickness of the rolled material in the longitudinal direction is within 10 μm.
In the solution heat treatment step [step 6], the first temperature rise rate from 25 ° C. to 600 ° C. is 80 ° C./s or more, and the second temperature rise rate from 600 ° C. to the maximum reached temperature is 20 ° C./s or less. The rolled material is heat-treated at a cooling rate of 100 ° C / s or higher from the maximum temperature reached to 300 ° C.
The method for producing a copper alloy plate, which comprises holding the rolled material within 1 hour or more and 10 hours or less in a temperature range of 300 ° C. or higher and 550 ° C. or lower in the aging heat treatment step [step 7]. The method for producing a copper alloy plate material according to claim 7, further comprising an intermediate cold rolling step [step A] between the solution heat treatment step [step 6] and the aging heat treatment step [step 7]. The method for producing a copper alloy plate according to claim 7 or 8, further comprising a finish cold rolling step [step B1] and a tempering annealing step [step B2] in this order after the aging heat treatment step [step 7]. ..

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