WO2018198995A1

WO2018198995A1 - Copper alloy sheet and method for manufacturing same

Info

Publication number: WO2018198995A1
Application number: PCT/JP2018/016389
Authority: WO
Inventors: 岳己磯松; 翔一檀上; 樋口　優
Original assignee: 古河電気工業株式会社
Priority date: 2017-04-26
Filing date: 2018-04-23
Publication date: 2018-11-01
Also published as: JP7145847B2; JPWO2018198995A1; KR20200002779A; CN110573635B; CN110573635A; KR102499442B1

Abstract

Provided is a copper alloy sheet that is manufactured using a Cu-Co-Si-based alloy and has excellent press punching processability while having high strength and high conductivity. The copper alloy sheet has an alloy composition including 0.3-1.9 mass% of Co, 0.1-0.5 mass% of Si, and the balance Cu and inevitable impurities, wherein the proportion, in the total crystal grain boundary, of the total quantity of Σ7 grain boundary and Σ9 grain boundary, which are special grain boundaries, is 1.5% or more, the proportion being obtained from the result of measurement by an EBSD method, the ratio Σ9/Σ7 is 1.0-5.0, and the orientation density of an α-fiber (Φ1 = 0°-45°) is within the range of 3.0-25.0.

Description

Copper alloy sheet and manufacturing method thereof

The present invention relates to a copper alloy sheet material applied to, for example, lead frames, connectors, terminal materials, relays, switches, sockets and the like for in-vehicle components and electrical / electronic devices, and a manufacturing method thereof.

Copper alloy sheet materials are widely used in applications such as lead frames, connectors, terminal materials, relays, switches, sockets, etc. for in-vehicle components and electrical / electronic devices. The characteristic items required for the copper alloy sheet used for such applications include tensile strength, yield strength (yield stress), bending workability, conductivity, fatigue characteristics, and the like.

In recent years, the required characteristics for copper alloy materials have become more severe as electrical and electronic devices and in-vehicle parts become more functional and denser. In particular, for copper alloy plate materials for terminals, reduction in weight and reduction in material usage are being studied by thinning and narrowing the material. In order to ensure the contact pressure in the leaf spring portion formed of the thin plate material as described above, it is necessary to increase the material strength.

In addition, since electric / electronic parts are generally formed by pressing or bending a plate material, the plate material must have excellent press punching workability. In particular, in the case of a copper alloy sheet for a terminal, if the press punching process is inferior, the shape of the cut surface when the press punching process is performed becomes unstable. Along with this, there is a problem in that the arrangement intervals between the terminals formed in a row cannot be made uniform, and variations occur, and variations in size and shape tend to occur among the terminals. Since this is not desirable in manufacturing on-vehicle components and electrical / electronic components, the copper alloy sheet material must also have excellent press punching workability.

Furthermore, terminals used for high current applications are required to be formed of a copper alloy material having high conductivity.

In recent years, with the increase in the battery capacity of electronic devices and the increase in the size of liquid crystal displays, the value of current flowing through terminals in terminals and charging terminals has increased.

Conventionally, Cu-Ni-Si alloys (Corson alloys), which are high-strength copper alloys strengthened mainly by precipitation strengthening and work hardening, have been widely used as copper alloy materials for electrical and electronic equipment and automobiles. Has been.

However, the Cu—Ni—Si alloy has a conductivity of about 50% IACS at the maximum, and when it is energized with a large current, the amount of heat generated by resistance increases, and heat reduces the spring property of the contact portion and fixes the terminal. Since the function of the terminal may be remarkably lowered due to deterioration of the mold or the like, it is not suitable for use as a terminal material for large current.

Therefore, it is required to develop a terminal material that can replace the Cu—Ni—Si alloy. For example, in Patent Document 1, a Cu—Co—Si alloy is used instead of a Cu—Ni—Si alloy, and the frequency of equiaxed grains and twin grain boundaries is controlled in the recrystallized structure. It is disclosed that bending workability and conductivity can be improved. However, Patent Document 1 does not discuss any press punching workability.

Japanese Patent No. 5534610

An object of the present invention is to provide a copper alloy sheet using a Cu—Co—Si based alloy, having high strength and high electrical conductivity, and having excellent press punching workability.

The copper alloy sheet material of the present invention controls the Σ7 grain boundary and the Σ9 grain boundary with respect to all the grain boundaries, and exhibits α-fiber (Φ1 = 0 ° to 45 °) indicating a rolling texture and a recrystallization texture. By developing it, the load concentration on the surface where the material and the die come into contact during press processing is suppressed, and the fluctuation height of the boundary line between the sag (surface) and the shear surface specified from the cut surface generated by press punching is small. Become. As a result, the inventors have found that the press punching processability is remarkably improved, and the gap between the terminals formed continuously and the variation in the size and shape of the terminals are reduced, and the present invention is completed. It came.

That is, the gist configuration of the present invention is as follows.
(1) From the result of having an alloy composition containing 0.3 to 1.9% by mass of Co and 0.1 to 0.5% by mass of Si, with the balance being Cu and inevitable impurities, measured by the EBSD method. The ratio of the total amount of the special grain boundary Σ7 grain boundary and Σ9 grain boundary in the total crystal grain boundary obtained is 1.5% or more, Σ9 / Σ7 is 1.0 to 5.0, α− A copper alloy sheet characterized in that the orientation density of fiber (Φ1 = 0 ° to 45 °) satisfies a range of 3.0 to 25.0.
(2) Containing 0.3 to 1.9% by mass of Co and 0.1 to 0.5% by mass of Si, 0.05 to 1.0% by mass of Cr, and 0.05 to 0. 7 mass%, Fe 0.02-0.5 mass%, Mg 0.01-0.3 mass%, Mn 0.01-0.5 mass%, Zn 0.01-0.15 mass % And Zr containing at least one component selected from the group consisting of 0.01 to 0.15% by mass, the balance having an alloy composition consisting of Cu and inevitable impurities, obtained from the results of measurement by the EBSD method The ratio of the total amount of the special grain boundary Σ7 grain boundary and Σ9 grain boundary in all the grain boundaries is 1.5% or more, Σ9 / Σ7 is 1.0 to 5.0, α-fiber (Φ1 = 0 ° to 45 °), a copper alloy sheet characterized by satisfying a range of 3.0 to 25.0.
(3) The copper alloy sheet according to (2) above, containing a total of 1.5% by mass or less of at least two components selected from the group consisting of Cr, Ni, Fe, Mg, Mn, Zn and Zr.
(4) The shear plane specified by observing the cut surface by press punching with a scanning electron microscope (SEM), wherein the tensile strength in the rolling parallel direction is 500 MPa or more, the electrical conductivity exceeds 50% IACS. As for the fracture surface, the difference Δt between the maximum value tmax and the minimum value tmin of the total dimension measured in the sheet thickness direction is 30% or less of the sheet thickness T, as described in any one of (1) to (3) above. Copper alloy sheet material.
(5) A method for producing the copper alloy sheet according to any one of (1) to (4) above,
A copper alloy material having the above alloy composition is cast into a casting step [Step 1], a first face grinding step [Step 2], a homogenization heat treatment step [Step 3], a hot rolling step [Step 4], and a water cooling step [Step 5]. ], Second face milling step [step 6], first cold rolling step [step 7], solution heat treatment step [step 8], aging heat treatment step [step 9], second cold rolling step [step 10]. And an annealing step [Step 11] are sequentially performed.
(6) A method for producing the copper alloy sheet according to any one of (1) to (4) above,
A copper alloy material having the above alloy composition is cast into a casting step [Step 1], a first face grinding step [Step 2], a homogenization heat treatment step [Step 3], a hot rolling step [Step 4], and a water cooling step [Step 5]. ], Second face milling step [step 6], first cold rolling step [step 7], solution heat treatment step [step 8], second cold rolling step [step 10], aging heat treatment [step 9], A method for producing a copper alloy sheet material, comprising sequentially performing a third cold rolling step [Step 12] and an annealing step [Step 11].
(7) A method for producing the copper alloy sheet according to any one of (1) to (4) above,
A copper alloy material having the above alloy composition is cast into a casting step [Step 1], a first face grinding step [Step 2], a homogenization heat treatment step [Step 3], a hot rolling step [Step 4], and a water cooling step [Step 5]. ], A second face milling step [Step 6], a first cold rolling step [Step 7], an aging heat treatment step [Step 9], and a second cold rolling step [Step 10]. A method for producing an alloy sheet.

According to the present invention, it has become possible to provide a copper alloy sheet material that uses a Cu—Co—Si based alloy, has high strength and high conductivity, and is excellent in press punching workability.

FIG. 1 is a typical crystal orientation distribution diagram of a copper alloy sheet material measured by EBSD and obtained from ODF (orientation distribution function) analysis. In FIG. 1, it is indicated by Euler angles in three directions, ie, a direction RD parallel to the rolling direction and a sheet width direction TD, which are orthogonal to the two axes in the rolling surface, and a normal direction ND of the rolling surface. The azimuth rotation is denoted as Φ, the ND axis azimuth rotation as Φ ₁ , and the TD axis azimuth rotation as Φ ₂ . FIG. 2 is a partial perspective view schematically showing the copper alloy sheet according to the embodiment of the present invention in a state where a cut surface after press punching is visible.

Hereinafter, preferred embodiments of the copper alloy sheet according to the present invention will be described in detail below.
The copper alloy sheet according to the present invention has an alloy composition containing 0.3 to 1.9% by mass of Co and 0.1 to 0.5% by mass of Si, with the balance being Cu and inevitable impurities. The total of the special grain boundary Σ7 grain boundary and Σ9 grain boundary with respect to all crystal grain boundaries obtained from the results measured by the method is 1.5% or more, Σ9 / Σ7 is 1.0 to 5.0, The orientation density of α-fiber (Φ1 = 0 ° to 45 °) satisfies the range of 3.0 to 25.0.

Here, the “copper alloy sheet” is obtained by processing a copper alloy material (before processing and having a predetermined alloy composition) into a plate shape, having a specific thickness and being stable in shape. This means something with a spread in the direction of the cage plane, and in the broad sense includes strips. In the present invention, the thickness of the plate material is not particularly limited, but is preferably 0.05 to 1.0 mm, more preferably 0.06 to 0.8 mm.

[Ingredient composition]
First, the component composition and action of the copper alloy sheet according to the present invention will be described.

<Essential component>
The copper alloy sheet according to the present invention contains Co and Si as essential components.
(Co: 0.3 to 1.9% by mass)
Co is finely precipitated in the Cu matrix (matrix) as a second phase particle precipitate made of a single substance or a compound with Si, for example, with a size of about 50 to 500 nm. This precipitate is an important component that acts to precipitate and harden by suppressing dislocation movement, and further suppresses grain growth and raises the material strength by refining crystal grains, and also improves bending workability. is there. In order to exhibit such an effect, the Co content needs to be 0.3% by mass or more. In addition, Co has a lower rate of decrease in conductivity when dissolved than Ni, but when the Co content exceeds 1.9% by mass, the decrease in conductivity becomes significant, exceeding 50% IACS. Since the conductivity cannot be obtained, the Co content needs to be 1.9% by mass or less. For example, in the case of a general Cu—Ni—Si based alloy (Cu-2.3 mass% Ni—0.65 mass% Si), the conductivity is about 38% IACS, but the Co content is 0.3%. The copper alloy sheet material of the present invention in the range of ˜1.9 mass% has a high value of 60% IACS or higher in electrical conductivity. Further, the tensile strength of the copper alloy sheet of the present invention depends on the production conditions, but by adopting specific production conditions, a copper alloy made of a Cu-Ni-Si alloy can be obtained at about 600 MPa after aging precipitation. High strength equivalent to that of plate material can be obtained. In order to satisfy both properties of tensile strength and conductivity in a balanced manner, the Co content is preferably in the range of 0.8 to 1.6% by mass.

(Si: 0.1-0.5% by mass)
Si is finely precipitated in the Cu matrix (matrix) as precipitates of second phase particles made of a compound together with Co, Cr, and the like. This precipitate is an important component having the effect of precipitating and hardening by suppressing dislocation movement, and further suppressing the grain growth and increasing the material strength by refining crystal grains. In order to exert such an effect, it is necessary to make the Si content 0.1% by mass or more. Further, if the Si content exceeds 0.5% by mass, the decrease in conductivity becomes remarkable, and the conductivity exceeding 50% IACS cannot be obtained. Therefore, the Si content is reduced to 0.5% by mass or less. There is a need to. In order to satisfy both properties of tensile strength and electrical conductivity in a well-balanced manner, the Si content is preferably in the range of 0.2 to 0.5% by mass.

<Optional components>
In addition to the essential components of Co and Si, the copper alloy sheet material of the present invention further includes, as optional components, 0.05 to 1.0% by mass of Cr and 0.05 to 0.7% by mass of Ni. %, Fe 0.02 to 0.5 mass%, Mg 0.01 to 0.3 mass%, Mn 0.01 to 0.5 mass%, Zn 0.01 to 0.15 mass%, and Zr may contain at least one component selected from the group consisting of 0.01 to 0.15% by mass.

(Cr: 0.05 to 1.0% by mass)
Cr is finely precipitated in the Cu matrix (matrix) as a compound or simple substance, for example, in the form of a precipitate having a size of about 50 to 500 nm. This precipitate is a component having an action of precipitating and hardening by suppressing dislocation movement, and further suppressing the grain growth and increasing the material strength by refining the crystal grains and improving the bending workability. In order to exhibit this effect, the Cr content is preferably 0.05% by mass or more. Moreover, if Cr content is 1.0 mass% or less, the fall of electrical conductivity will not become remarkable and there will be no tendency for the electrical conductivity exceeding 50% IACS not to be obtained. Therefore, the Cr content is set to 0.05 to 1.0% by mass.

(Ni: 0.05 to 0.7% by mass)
Ni is finely precipitated in the matrix (matrix) of Cu as a compound or simple substance, for example, in the form of a precipitate having a size of about 50 to 500 nm. This precipitate is a component having an action of precipitating and hardening by suppressing dislocation movement, and further suppressing the grain growth and increasing the material strength by refining the crystal grains and improving the bending workability. In order to exert this effect, the Ni content is preferably 0.05% by mass or more. Moreover, if Ni content is 0.7 mass% or less, the fall of electrical conductivity will not be remarkable and there will be no tendency for the electrical conductivity exceeding 50% IACS not to be obtained. Therefore, the Ni content is 0.05 to 0.7% by mass.

(Fe: 0.02-0.5% by mass)
Fe is a component having an effect of improving product characteristics such as conductivity, strength, stress relaxation characteristics, and plating properties. In order to exert such an effect, the Fe content is preferably 0.02% by mass or more. Moreover, if Fe is 0.5 mass% or less, there is no tendency for electrical conductivity to fall. Therefore, the Fe content is set to 0.02 to 0.5% by mass.

(Mg: 0.01 to 0.3% by mass)
Mg is a component having an effect of improving the stress relaxation resistance. In order to exert such an effect, the Mg content is preferably 0.01% by mass or more. Further, if the Mg content is 0.3% by mass or less, the conductivity does not tend to decrease. Therefore, the Mg content is set to 0.01 to 0.3% by mass.

(Mn: 0.01 to 0.5% by mass)
Mn dissolves in the matrix phase to improve wire drawing workability, suppresses rapid development of grain boundary reactive precipitation, and enables control of discontinuous precipitation cell structure caused by grain boundary reactive precipitation. It is a component having the action of In order to exert such an effect, the Mn content is preferably 0.01% by mass or more. Moreover, if content of Mn is 0.5 mass% or less, there exists no possibility that the fall of electrical conductivity or the deterioration of bending workability may arise. Therefore, the Mn content is set to 0.01 to 0.5% by mass.

(Zn: 0.01 to 0.15% by mass)
Zn is a component that has an effect of improving bending workability and improving adhesion and migration characteristics of Sn plating and solder plating. In order to exert such an effect, the Zn content is preferably 0.01% by mass or more. Moreover, if Zn content is 0.15 mass% or less, there is no tendency for electroconductivity to fall. Therefore, the Zn content is set to 0.01 to 0.15% by mass.

(Zr: 0.01 to 0.15 mass%)
Zr is a component having an effect of mainly refining crystal grains and improving strength and bending workability. In order to exert such an effect, the Zr content is preferably set to 0.01 mass or more. Moreover, if Zr content is 0.15 mass% or less, a compound will be formed and there will be no tendency for electrical conductivity and press punching workability to fall remarkably. Therefore, the Zr content is set to 0.01 to 0.15% by mass.

(Total content when containing at least two optional additional components)
In the case where at least two optional additive components selected from the group consisting of Cr, Ni, Fe, Mg, Mn, Zn and Zr are contained, the total content is preferably 1.5% by mass or less. This is because if the total content is 1.5% by mass or less, press punching workability and electrical conductivity are not greatly reduced. For this reason, the said total content shall be 1.5 mass% or less.

<Remainder>
The balance consists of Cu and inevitable impurities other than the essential components and optional components described above. The “inevitable impurities” referred to here are mostly metal products that are present in raw materials or inevitably mixed in the manufacturing process, and are essentially unnecessary, but are trace amounts, It is an acceptable impurity because it does not affect the product characteristics.

[Rolling texture]
In the present invention, the ratio of the total amount of the special grain boundary Σ7 grain boundary and Σ9 grain boundary in the total grain boundary obtained from the result of measurement by the EBSD method is 1.5% or more, and Σ9 / Σ7 1.0 to 5.0, and the orientation density of α-fiber (Φ1 = 0 ° to 45 °) must satisfy the range of 3.0 to 25.0. . The “orientation density” here is also expressed as a crystal orientation distribution function (ODF), where the random crystal orientation distribution is set to 1, and the number of times of accumulation is greater than that. It is used to quantitatively analyze the abundance ratio of the crystal orientation of the texture and the dispersion state. The orientation density is based on the EBSD and X-ray diffraction measurement results, and the crystal orientation distribution analysis by the series expansion method based on three or more kinds of positive point map measurement data such as (100), (110), (112) positive point map Calculated by the method. The special grain boundaries Σ7 and Σ9 are called special grain boundaries and are crystal grain boundaries that form a corresponding lattice. When there is no simple orientation relationship between crystal grains, Σ is large and a grain boundary that does not have special properties is called a random grain boundary. α-fiber refers to the fact that the crystal orientation group that develops when pure copper is rolled and recrystallized is connected like a fiber when shown on the ODF map. The orientation density of α-fiber changes depending on the frequency of rolling and recrystallization.

In order to improve the press punching workability of the copper alloy sheet material, the present inventors have intensively studied the relationship with the rolling texture. As a result, the alloy composition is limited to the above range, the ratio of the total amount of the special grain boundary Σ7 grain boundary and Σ9 grain boundary in the total grain boundary is 1.5% or more, and Σ9 / Σ7 is 1.0 to By controlling the orientation density of α-fiber (φ ₁ = 0 to 45 °) within the range of 3.0 to 25.0, the punching workability is greatly improved. I found out.

That is, Σ7 and Σ9 of the special grain boundaries have relatively low grain boundary energy compared to other special grain boundaries, and the ratio of the total amount of the special grain boundaries Σ7 grain boundary and Σ9 grain boundary in the total crystal grain boundary is This is because, if it is 1.5% or more, even in the case of processing that is locally heavily loaded such as press processing, it is easy to deform against external force, and excellent press punching workability can be obtained stably.

Also, the Σ9 grain boundary has a greater contribution to press punching workability than the Σ7 grain boundary. On the other hand, the Σ7 grain boundary is superior to other special grain boundaries, although it contributes less to press punching workability than the Σ9 grain boundary. Note that each of the Σ7 and Σ9 grain boundaries has a lower grain boundary energy than the other special grain boundaries, and is considered to contribute to press punchability during processing. For this reason, by limiting Σ9 / Σ7 to 1.0 to 5.0, excellent press punchability can be exhibited.

Further, by limiting the orientation density of α-fiber (in the range of φ ₁ = 0 ° to 45 °) within the range of 3.0 or more and 25.0 or less, high strength can be obtained in addition to press punchability. It is possible to obtain excellent strength by manufacturing with the manufacturing method described later.

FIG. 1 is a typical crystal orientation distribution diagram of a copper alloy sheet measured by EBSD and obtained from an ODF (orientation distribution function) analysis, which is a biaxial orthogonal direction in a rolling plane, The Euler angles in the three directions of the parallel direction RD and the sheet width direction TD and the normal direction ND of the rolled surface are shown, that is, the RD axis orientation rotation is Φ, the ND axis orientation rotation is Φ ₁ , and the TD axis orientation shows the rotating [Phi _2. Here, α-fiber is accumulated in a range of φ ₁ = 0 ° to 45 °.

The EBSD method was used for the analysis of the rolling texture in the present invention. The EBSD method is an abbreviation for Electron Backscatter Diffraction, and is a crystal orientation analysis technique using reflected electron Kikuchi line diffraction that occurs when a sample is irradiated with an electron beam in a scanning electron microscope (SEM). In the EBSD measurement in the present invention, a sample area of 800 μm × 1600 μm containing 200 or more crystal grains was scanned and measured in 0.1 μm steps. The measurement area and the scanning step may be determined according to the size of crystal grains of the sample. As for the orientation difference, the orientation difference between adjacent measurement points of 10 ° or more is regarded as a crystal grain boundary. For analysis of the crystal grains after the measurement, analysis software OIM Analysis (trade name) manufactured by TSL Solutions was used. Information obtained in the analysis of crystal grains by EBSD includes information up to a depth of several tens of nm at which the electron beam penetrates the sample. Further, the measurement location in the plate thickness direction is preferably near the position of 1/8 to 1/2 times the plate thickness t from the sample surface.

In this specification, the crystal orientation display method includes a crystal plane index (h k l) perpendicular to the Z axis (parallel to the rolling plane (XY plane)) and a vertical axis (parallel to the YZ plane) to the X axis. Using the index [u v w] of the crystal direction, it is expressed in the form of (h k l) [u v w]. Also, the equivalent orientation under the cubic symmetry of the copper alloy, such as (1 3 2) [6 -4 3] and (2 3 1) [3 -4 6] A parenthesis representing the generic name is used, and {h k l} <u v w> is used. Typical crystal orientations include Brass orientation {011} <211>, S orientation {123} <634>, Copper orientation {112} <111>, Goss orientation {110} <001>, RDW orientation {012} <100. >, BR orientation {236} <385> and the like. Here, α-fiber is in the range of φ ₁ = 0 ° to 45 °, and exists as an alloy-type fiber texture that continuously changes from the Goss orientation to the Brass orientation. The alloy of the copper alloy sheet material of the present invention The component is an alloy-type texture, which is a structure obtained by controlling the additive elements Co and Si within a specified range. The presence of α-fiber within a specified range can significantly improve press punching workability.

[Tensile strength]
In the present invention, the tensile strength in the rolling parallel direction is preferably 500 MPa or more. If the tensile strength in the rolling parallel direction is 500 MPa or more, there is no tendency for the strength of the plate material to be insufficient when the terminal is formed from a thin plate or narrowed plate material, and sufficient contact pressure at the leaf spring portion of the terminal This is because there is no possibility that it cannot be secured.

[conductivity]
In the present invention, it is preferable that the electrical conductivity exceeds 50% IACS. If the electrical conductivity exceeds 50% IACS, the resistance heating value will not be large even when energized with a large current, and the function of the terminal will be reduced due to a decrease in the spring property of the contact part due to heat or deterioration of the mold for fixing the terminal. This is because there is no risk of significant decrease.

[Shape of cut surface by press punching]
In the present invention, the shear plane and the fractured surface specified by observing the cut surface by press punching with a scanning electron microscope (SEM) are the difference between the maximum value tmax and the minimum value tmin of the total dimension measured in the plate thickness direction. Δt is preferably 30% or less of the plate thickness T.

FIG. 2 is a partial perspective view of a copper alloy sheet according to a representative embodiment. The copper alloy sheet 1 shown in FIG. 2 shows a state in which a press punching process is performed by lowering an upper die (punch) while being fixed on a lower die (die) (not shown), A surface (cut) 2 is provided. Further, the cut surface 2 is configured in the order of the sag 3, the sheared surface 4 and the fracture surface 5 from the upper surface 1 a side of the pressed copper alloy sheet material 1. A so-called burr 6 is also formed, which is a thin fin-like portion protruding outward from the regular cross-sectional shape.

The present inventors pay particular attention to the fluctuation height Δt of the boundary line 7 between the sag (surface) 3 and the shearing face 4, and this fluctuation height Δt, that is, a predetermined thickness with respect to the plate thickness T of the copper alloy sheet material 1. More specifically, the cut surface 2 formed by press punching was observed with a scanning electron microscope (SEM). As a result, the present inventors control the difference Δt between the maximum value tmax and the minimum value tmin of the total dimension obtained by measuring the specified shear surface 4 and fracture surface 5 in the plate thickness direction to 30% or less of the plate thickness T. As a result, it has been found that the press punching processability is remarkably improved. And as above-mentioned, control of this fluctuation height (DELTA) t is obtained from the result measured by the EBSD method, and the ratio of the total amount of the special grain boundary (SIGMA) 7 grain boundary and (SIGMA9) grain boundary which occupies for all the crystal grain boundaries is 1. 5% or more, Σ9 / Σ7 is 1.0 to 5.0, and the orientation density of α-fiber (Φ1 = 0 ° to 45 °) is within the range of 3.0 to 25.0. Can be realized. When the fluctuation height Δt exceeds 30% of the plate thickness T, the press punching processability is inferior, and there is a tendency that the distance between the terminals formed continuously and the variation in the size and shape of the terminals increase.

In addition, since the cut surface 2 formed by the press punching process has generation | occurrence | production of the burr | flash 6, etc., the sagging 3 and the burr | flash 6 generate | occur | produce in the board thickness T of the copper alloy board | plate material 1 and the cut surface 2 after a process. Therefore, since the thickness T of the copper alloy sheet 1 cannot be measured correctly, the total dimension of the shear surface 4 and the fracture surface 5 is measured based on the position of the lower surface 1b of the copper alloy sheet 1 that has not been processed. To do.

<Method for producing copper alloy sheet>
Next, the specific example of the manufacturing method of the copper alloy sheet | seat material of this invention is demonstrated below.
(Production method A)
In the method for producing a copper alloy sheet according to the present invention, in order to remove the oxide film formed on the surface of the ingot obtained in the casting step (step 1) for melting the copper alloy material, both sides of the front and back sides are each 0.5 mm or more. After performing the first chamfering step (step 2) of scraping with a thickness, a homogenization heat treatment step (step 3) is performed at a holding temperature of 800 to 1200 ° C. and a holding time of 0.1 to 10 hours, and then a rolling temperature of 600 The hot rolling step (step 4) was performed under the conditions of ˜1100 ° C., rolling number of 4 times or more, and total processing rate of 60% or more, followed by rapid cooling by the water cooling step (step 5). Thereafter, in order to remove the oxide film on the surface, a second chamfering step (step 6) is performed in which both the front and back surfaces of the hot-rolled material are each cut to a thickness of 0.5 mm or more. Thereafter, after performing the first cold rolling step (step 7) under the conditions of the rolling number of times of 2 times or more and the total processing rate of 50% or more, the heating rate is 1 to 150 ° C./second, the ultimate temperature is 800 to 1000 ° C., A solution heat treatment step (step 8) is performed at a holding time of 1 to 300 seconds and a cooling rate of 1 to 200 ° C./second, and then an aging heat treatment step at an ultimate temperature of 300 to 650 ° C. and a holding time of 0.2 to 15 hours (Step 9) is performed. Next, after performing the second cold rolling step (step 10) under the condition that the number of rolling is 2 times or more and the total processing rate is 5% or more, annealing is performed at an ultimate temperature of 200 to 600 ° C. and a holding time of 1 to 3600 seconds. A process (process 11) is performed. In this way, the copper alloy sheet material of the present invention is produced.

(Production method B)
Moreover, as another manufacturing method of a copper alloy plate material, after performing the process 1 to the process 8, the aging heat treatment process (process 9) is performed after the second cold rolling process (process 10) is performed, and then further In addition, the number of times of rolling is two times or more, the third cold rolling step (step 12) may be performed under conditions of a total processing rate of 10% or more, and then the annealing step (step 11) may be performed. It is possible to produce the copper alloy sheet of the present invention.

(Manufacturing method C)
Furthermore, as another manufacturing method of the copper alloy material, after performing from step 1 to step 7, the aging heat treatment step (step 9) is performed without performing the solution heat treatment step (step 8), and then the second A cold rolling step (step 10) may be performed, and the copper alloy sheet material of the present invention can also be produced by such a method.

The copper alloy material contains 0.3 to 1.9% by mass of Co and 0.1 to 0.5% by mass of Si. Further, if necessary, 0.05 to 1.0% by mass of Cr and Ni 0.05 to 0.7 mass%, Fe 0.02 to 0.5 mass%, Mg 0.01 to 0.3 mass%, Mn 0.01 to 0.5 mass%, Zn 0. It contains at least one component selected from the group consisting of 01 to 0.15% by mass and Zr from 0.01 to 0.15% by mass, and the balance has an alloy composition consisting of Cu and inevitable impurities.

The “rolling ratio” here is a value expressed as a percentage by dividing the value obtained by subtracting the cross-sectional area after rolling from the cross-sectional area before rolling by the cross-sectional area before rolling and multiplying by 100. That is, it is represented by the following formula.
[Rolling ratio] = {([Cross sectional area before rolling] − [Cross sectional area after rolling]) / [Cross sectional area before rolling]} × 100 (%)

In the present invention, a homogenization heat treatment step (step 3), a hot rolling step (step 4), and an aging heat treatment step (step 9), which are particularly common steps among the structures constituting the manufacturing methods A to C described above. It is important to control. That is, the temperature increase rate in the homogenization heat treatment step is 10 to 110 ° C./second, the holding temperature is 950 to 1250 ° C., the cooling start temperature in the hot rolling step (step 4) is 680 to 850 ° C., and the cooling rate is 20 to It is necessary to set the temperature to 130 ° C./second, the temperature reached in the aging heat treatment step (step 9) to 450 to 650 ° C., and the holding time to 500 to 20000 seconds. Further, in order to sufficiently develop the rolling texture and control the orientation density of α-fiber within an appropriate range, the aging heat treatment step (step 9) needs to be heat-treated within the above range.

If the heating rate in the homogenization heat treatment step (step 3) is 10 ° C./second or more or 110 ° C./second or less, or the holding temperature is 950 ° C. or more, the crystallization product produced during casting is sufficiently dissolved and produced. In a copper alloy sheet, a satisfactory level of strength and electrical conductivity can be obtained. On the other hand, when the holding temperature in the homogenization heat treatment step (step 3) is 1250 ° C. or lower, the vicinity of the crystal grain boundary partially becomes a liquid phase and cracks during hot rolling are likely to occur, and there is no case where it cannot be produced. Because. In addition, when the cooling start temperature in the hot rolling step (step 4) is 680 ° C. or higher or the cooling rate is 20 ° C./second or more, coarse precipitation of solute elements proceeds during cooling, and the produced copper alloy sheet is satisfactory. This is because there is no possibility that the strength and conductivity of the level cannot be obtained. On the other hand, if the cooling start temperature in the hot rolling step (step 4) is 850 ° C. or lower or the cooling rate is 130 ° C./second or lower, the formation of the rolled structure becomes sufficient, which adversely affects the press punchability after the final step. There is no. Furthermore, when the temperature reached in the aging heat treatment step (step 9) is 450 ° C. or higher or the holding time is 500 seconds or longer, the amount of aging precipitation is insufficient and the strength and conductivity do not tend to be insufficient. On the other hand, when the temperature reached in the aging heat treatment step (step 9) is 650 ° C. or less or 20000 seconds or less, the strength of the precipitate does not tend to be insufficient due to coarsening of the precipitate.

Therefore, in the present invention, the target structure and characteristics are obtained by appropriately controlling the conditions of the homogenization heat treatment step (step 3), the hot rolling step (step 4) and the aging heat treatment step (step 9). Is obtained.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, All the aspects included in the concept and claim of this invention are included, and it modifies | changes within the scope of the present invention. be able to.

Next, in order to further clarify the effects of the present invention, examples will be described below, but the present invention is not limited thereto.

(Invention Examples 1 to 16 and Comparative Examples 1 to 9)
Inventive Examples 1 to 16 and Comparative Examples 1 to 9 each contain Co and Si, and optional additional components to be added as necessary, so that the compositions shown in Table 1 are obtained, with the balance being Cu and inevitable impurities. The resulting copper alloy material was melted in a high-frequency melting furnace and cast (step 1) to obtain an ingot. In order to remove the oxide film formed on the surface of the ingot, after performing the first chamfering step (step 2) in which both the front and back surfaces are each cut to a thickness of 0.5 mm, the heating rate and holding shown in Table 2 are performed. A homogenization heat treatment step (step 3) is performed under temperature conditions, and then a hot rolling step (step 4) is performed under the conditions of the cooling start temperature and cooling rate shown in Table 2, followed by a water cooling step (step 5). ). Thereafter, in order to remove the oxide film on the surface, a second chamfering step (step 6) is performed in which both the front and back surfaces of the hot-rolled material are each cut to a thickness of 0.5 mm. Thereafter, after performing the first cold rolling step (step 7) so that the total processing rate becomes 50% or more, each step according to any one of the manufacturing methods A to C shown in Table 2 is sequentially performed, An alloy sheet was produced. Table 2 shows the ultimate temperature and holding time in the aging heat treatment step (step 9). For each produced copper plywood, the ratio of the total amount of special grain boundaries Σ7 grain boundary and Σ9 grain boundary in the total grain boundary, Σ9 / Σ7 ratio, orientation density of α-fiber (Φ1 = 0 ° -45 °) Table 2 also shows the ratio of fluctuation height Δt / plate thickness T.

[Evaluation methods]
Each copper alloy sheet produced was evaluated for the following characteristics.
(Measurement and analysis of crystal orientation by EBSD measurement)
The measurement was performed under the conditions of a measurement area of 64 × 10 ⁴ μm ² (800 μm × 800 μm) and a scan step of 0.1 μm by the EBSD method. The scan step was performed in 0.1 μm steps to measure fine crystal grains. In the analysis, an inverse pole figure IPF (Inverse Pole Figure) was confirmed from the EBSD measurement result of 64 × 10 ⁴ μm ^{2 in} the analysis. The electron beam was generated from thermionic electrons from the W filament of the scanning electron microscope. The probe diameter at the time of measurement is about 0.015 μm. OIM5.0 (trade name) manufactured by TSL Solutions was used as the measuring device for the EBSD method. As for the Σ9 / Σ7 ratio, the Σ7 grain boundary and the Σ9 grain boundary were calculated from the CBSD (Coincidence Site Lattice) on the measurement surface using the analysis software (OIM Analysis). The orientation density of α-fiber (Φ1 = 0 ° to 45 °) can be obtained by analyzing the results of EBSD using an analysis software (OIM Analysis) from a particular orientation function: ODF (Orientation Distribution Functions). Extracted. Regarding the difference in orientation, those having an orientation difference of 10 ° or more between adjacent measurement points were regarded as crystal grain boundaries.

(Tensile test)
In accordance with JIS Z 2241: 2011, three test pieces were cut out from each copper alloy sheet along the rolling parallel direction and measured, and the average value (MPa) is shown in Table 2. In this example, the case where the tensile strength was 500 MPa or more was evaluated as being at an acceptable level.

(Conductivity (EC))
The electrical conductivity of each copper alloy sheet was calculated from specific resistance values measured by a four-terminal method in a thermostatic chamber maintained at 20 ° C. (± 0.5 ° C.). In addition, the distance between terminals was 100 mm. In addition, in the present Example, the case where the electrical conductivity of a board | plate material exceeded 50% IACS was evaluated as the pass, and the case below 50% IACS was evaluated as the failure.

(Press punching workability)
Each prepared copper alloy sheet is adjusted so that the clearance between the upper mold (punch) and the lower mold (die) is 5.0% of the sheet thickness T, punched, and length dimension: 3.0 mm. , Width dimension: 1.0 mm, and the length dimension is punched so as to be perpendicular to the rolling direction to prepare a sample. Of the cut surfaces formed in each sample, the length dimension Observe an orthogonal cut surface (a surface parallel to the width dimension). The sample after pressing is fixed and observed with a SEM at 100 to 500 times. For SEM observation, SEMEDX TypeM manufactured by Hitachi, Ltd. was used. For the sheared surface and fractured surface identified by observing the cut surface by press punching with a scanning electron microscope (SEM), the difference Δt between the maximum value tmax and the minimum value tmin of the total dimension measured in the plate thickness direction was measured. . The measured Δt is 30% or less of the plate thickness T, “○” is assumed that the press punching workability is at an acceptable level, and the press punching workability is at an acceptable level when it exceeds 30% of the plate thickness T. It is shown in Table 2 as “x” as being unacceptable.

From the evaluation results shown in Table 2, in all of inventive examples 1 to 16, the alloy composition, the ratio of the total amount of the special grain boundary Σ7 grain boundary and Σ9 grain boundary in the total grain boundary, Σ9 / Σ7 ratio and α− Since all of the orientation densities of the fibers (Φ1 = 0 ° to 45 °) are within the appropriate range of the present invention, the tensile strength, conductivity and press punching workability were excellent. On the other hand, Comparative Examples 1 to 9 show the alloy composition, the ratio of the total amount of the special grain boundary Σ7 grain boundary and Σ9 grain boundary in the total grain boundary, the Σ9 / Σ7 ratio and α-fiber (Φ1 = 0 ° to 45 °). ) Is outside the proper range of the present invention, and the press punching workability was inferior.

1 Copper alloy sheet 2 Cut surface 3 Sag (surface)
4 Shear surface 5 Fracture surface 6 Burr 7 Boundary line between sag (surface) 3 and shear surface 4 Δt Fluctuation height of boundary line tmax Maximum value of total dimension of shear surface 4 and fracture surface 5 measured in thickness direction tmin Minimum value of total dimensions of shear plane 4 and fracture surface 5 measured in the thickness direction

Claims

Obtained from the result of measurement by the EBSD method having an alloy composition containing 0.3 to 1.9% by mass of Co and 0.1 to 0.5% by mass of Si with the balance being Cu and inevitable impurities The ratio of the total amount of the special grain boundary Σ7 grain boundary and Σ9 grain boundary in all the grain boundaries is 1.5% or more, Σ9 / Σ7 is 1.0 to 5.0, α-fiber (Φ1 = 0 ° to 45 °), a copper alloy sheet characterized by satisfying a range of 3.0 to 25.0.
It contains 0.3 to 1.9% by mass of Co and 0.1 to 0.5% by mass of Si, and further 0.05 to 1.0% by mass of Cr and 0.05 to 0.7% by mass of Ni. Fe, 0.02 to 0.5 mass%, Mg 0.01 to 0.3 mass%, Mn 0.01 to 0.5 mass%, Zn 0.01 to 0.15 mass%, and Zr Including at least one component selected from the group consisting of 0.01 to 0.15 mass%, the balance having an alloy composition consisting of Cu and inevitable impurities, and the total crystal obtained from the result of measurement by the EBSD method The ratio of the total amount of the special grain boundary Σ7 grain boundary and Σ9 grain boundary in the grain boundary is 1.5% or more, Σ9 / Σ7 is 1.0 to 5.0, α-fiber (Φ1 = 0 ° A copper alloy sheet characterized by having an orientation density of ˜45 ° satisfying the range of 3.0 to 25.0.
The copper alloy sheet material according to claim 2, comprising a total of 1.5 mass% or less of at least two components selected from the group consisting of Cr, Ni, Fe, Mg, Mn, Zn and Zr.
Shear surface and fracture surface identified by observing the cut surface by press punching with a scanning electron microscope (SEM), the tensile strength in the rolling parallel direction is 500 MPa or more, the electrical conductivity exceeds 50% IACS The copper alloy sheet according to any one of claims 1 to 3, wherein a difference Δt between the maximum value tmax and the minimum value tmin of the total dimension measured in the sheet thickness direction is 30% or less of the sheet thickness T.
A method for producing a copper alloy sheet according to any one of claims 1 to 4,
A copper alloy material having the above alloy composition is cast into a casting step [Step 1], a first face grinding step [Step 2], a homogenization heat treatment step [Step 3], a hot rolling step [Step 4], and a water cooling step [Step 5]. ], Second face milling step [step 6], first cold rolling step [step 7], solution heat treatment step [step 8], aging heat treatment step [step 9], second cold rolling step [step 10]. And an annealing step [Step 11] are sequentially performed.
A method for producing a copper alloy sheet according to any one of claims 1 to 4,
A copper alloy material having the above alloy composition is cast into a casting step [Step 1], a first face grinding step [Step 2], a homogenization heat treatment step [Step 3], a hot rolling step [Step 4], and a water cooling step [Step 5]. ], Second face milling step [step 6], first cold rolling step [step 7], solution heat treatment step [step 8], second cold rolling step [step 10], aging heat treatment [step 9], A method for producing a copper alloy sheet material, comprising sequentially performing a third cold rolling step [Step 12] and an annealing step [Step 11].
A method for producing a copper alloy sheet according to any one of claims 1 to 4,
A copper alloy material having the above alloy composition is cast into a casting step [Step 1], a first face grinding step [Step 2], a homogenization heat treatment step [Step 3], a hot rolling step [Step 4], and a water cooling step [Step 5]. ], A second face milling step [Step 6], a first cold rolling step [Step 7], an aging heat treatment step [Step 9], and a second cold rolling step [Step 10]. A method for producing an alloy sheet.