WO2020152967A1 - Copper alloy plate material and method for manufacturing same - Google Patents

Abstract

A copper alloy plate material according to the present invention has an alloy composition comprising 0.3 to 2.5% by mass of Co, 0.1 to 0.7% by mass of Si and a remainder made up by Cu and unavoidable impurities. When a longitudinal section of the copper alloy plate material which is parallel to the rolling direction of the copper alloy plate material is subjected to a crystal orientation analysis by an EBSD method, the ratio of the area of a measurement spot region having a reliability index (CI value) of 0.2 or less to the total area of all of measurement spot regions is 40% or less. When the longitudinal section is divided into a pair of surface layer parts respectively including both surfaces of the plate material and a center part located between the pair of surface layer parts and the average value of the reliability indices (CI values) of the pair of surface layer parts is defined as CI_S and the average value of the reliability indices (CI values) of the center part is defined as CI_C, the ratio of CI_S to CI_C (i.e., CI_S/CI_C ratio) is 0.8 to 2.0 inclusive. The copper alloy plate material can achieve both of excellent bending workability and high strength at a high level.

Description

Copper alloy sheet and method for producing the same

The present invention relates to a copper alloy plate and a method for manufacturing the same.

As a copper alloy plate material, for example, a copper alloy plate material used for electric/electronic parts and automobile in-vehicle parts, conventionally, a Cu—Ni—Si-based alloy (which is a high-strength copper alloy mainly strengthened by precipitation strengthening or work hardening) ( Corson alloys) have been widely used.

However, the Cu-Ni-Si alloy has a maximum conductivity of about 50% IACS, and when it is energized with a large current, the amount of heat generated by resistance increases, which causes the spring property of the contact portion to deteriorate and the terminal to be fixed. It is not suitable for use as a terminal material for a large current because the function of the terminal may be significantly reduced due to deterioration of the mold.

Therefore, it is required to develop a terminal material to replace the Cu-Ni-Si alloy. For example, in Patent Document 1, a Cu—Co—Si based alloy is used in place of the Cu—Ni—Si based alloy, and the frequency of equiaxed grains and twin grain boundaries in the recrystallization structure is controlled to control the plate material. It is disclosed that bendability and conductivity can be improved.

However, the Cu—Co—Si alloy strip described in Patent Document 1 has not been examined in terms of strain that greatly affects bending workability and strength, and there is room for further improvement in bending workability and strength. there were.

Further, in Patent Document 2, in a copper alloy containing Mg in the range of 3.3 atomic% or more and 6.9 atomic% or less, the strain introduced during processing was measured by the SEM-EBSD method in the rolling width direction. On the other hand, it is said that the bending workability can be improved by keeping the value within the range defined by the ratio of the measurement points having a low CI value on the vertical surface (that is, the TD surface).

Further, in Patent Document 3, in titanium copper containing Ti in an amount of 2.0 to 4.0% by mass, the area ratio having a reliability index (CI value) of 0.2 or less measured by SEM-EBSD method for surface strain It is said that the bending workability can be improved by setting the ratio to 20% or less.

In both Patent Documents 2 and 3, improvement in bending workability is recognized, but there is no description about Cu—Co—Si alloys. In addition, in Patent Document 2, conductivity is 31.8 to 45. Only a low value in the range of 1% IACS was obtained, and the numerical value of conductivity is not shown in Patent Document 3.

Japanese Patent No. 5534610 Japanese Patent No. 5903838 Japanese Patent No. 6080822

An object of the present invention is to use a Cu—Co—Si alloy having a higher conductivity than a Cu—Ni—Si alloy, and to achieve excellent bending workability and high strength at a high level. And to provide a manufacturing method thereof.

The present inventor uses a copper alloy material having a Cu—Co—Si alloy composition having a higher electrical conductivity than Cu—Ni—Si alloy to produce a copper alloy sheet material by rolling. When a crystal orientation analysis was performed on a vertical cross section parallel to, by an electron backscattering diffraction (EBSD) method, the area ratio of a measurement spot region having a small reliability index (CI value) in the vertical cross section was controlled to be low, and by achieve an appropriate ratio of the average value of the reliability index (CI value) in each of the surface portion and the central portion of the longitudinal section (CI S _/ CI _C ratio), it is possible to develop processed structure, its As a result, they have found that the strength can be improved while ensuring bending workability, and have completed the present invention.

In order to achieve the above object, the gist of the present invention is as follows.
(I) A copper alloy plate containing 0.3 to 2.5 mass% of Co and 0.1 to 0.7 mass% of Si, and the balance of Cu and unavoidable impurities. The crystal orientation analysis performed on the longitudinal section parallel to the rolling direction of the alloy sheet material by the electron backscatter diffraction (EBSD) method showed that all the measurement of the measurement spot area where the reliability index (CI value) was 0.2 or less. The area ratio of the spot region is 40% or less, and the longitudinal section is divided into a pair of surface layer portions each including both surfaces of the plate material and a central portion located between the pair of surface layer portions. when the indicator is, the average value of the reliability index (CI value) of the surface layer portion of the pair and CI _S, the average value of the reliability index (CI value) of the central portion and CI _C, CI _C copper alloy sheet ratio CI _{S (CI S} / CI _C ratio), which is characterized in that 0.8 to 2.0 relative to.
(II) 0.3 to 2.5% by mass of Co and 0.1 to 0.7% by mass of Si, 0.05 to 1.0% by mass of Cr and 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 0.01 to 0.15 mass% % And Zr are at least one optional additive selected from the group consisting of 0.01 to 0.15 mass %, and the balance is a copper alloy sheet material having an alloy composition of Cu and inevitable impurities, A crystal orientation analysis performed by an electron backscattering diffraction (EBSD) method on a longitudinal section parallel to the longitudinal direction of the copper alloy plate material shows that a reliability index (CI value) is 0.2 or less in a measurement spot region. An area ratio of 40% or less in all the measurement spot regions, and a pair of surface layer portions each including both surfaces of the plate member in the longitudinal section, and a central portion located between the pair of surface layer portions. divided into bets, the average value of the reliability index (CI value) of the surface layer portion of the pair and CI _S, the average value of the reliability index (CI value) of the central portion when the CI _C, the ratio of the CI _S for CI _{C (CI} S / CI _C ratio), the copper alloy sheet which is characterized in that 0.8 to 2.0.
(III) The copper alloy plate material according to (II), which contains the optional additive component in a total amount of 1.5% by mass or less.
(IV) The tensile strength when stretched in parallel with the rolling direction is 600 MPa or more, the electrical conductivity is more than 50% IACS, and the W bending test according to Japan Copper and Brass Association (JCBA) T307:2007 is conducted. The root mean square roughness Rq on the bending outer surface of the bent portion after performing r/t=0 in the Goodway direction is 7.0 μm or less, (I) to (III) above. Copper alloy plate material.
(V) A method for producing the copper alloy sheet according to any one of (I) to (IV) above, which has a substantially same alloy composition as the alloy composition of the copper alloy sheet. The casting step [step 1], the first chamfering step [step 2], the homogenizing heat treatment step [step 3], the hot rolling step [step 4], the cooling step [step 5], the second chamfering step [ Step 6], the first cold rolling step [Step 7], the solution heat treatment step [Step 8], the aging heat treatment step [Step 9], the second cold rolling step [Step 10] and the annealing step [Step 11]. Sequentially, the temperature rising rate in the homogenizing heat treatment step [step 3] is set to 10 to 110° C./sec and the holding temperature is 950 to 1250° C., and the cooling start temperature in the surface layer portion of the plate material in the cooling step [step 5] Of 680 to 850° C. and an average cooling rate of 5 to 20° C./sec, the achievable temperature in the aging heat treatment step [step 9] is 450 to 650° C. and the holding time of 500 to 20000 sec, and the second cooling In the inter-rolling step [Step 10], when the processing rate per pass is 10% or more and 40% or less, and the rolling roll diameter is R, the processing amount is Δh, and the final plate thickness is h, the parameter M is A method for producing a copper alloy sheet material, which is represented by the following formula (1) and is 6 or more and 40 or less.
M={(R·Δh) ^0.5 }/h ··· (1)
(VI) After the solution heat treatment step [step 8] and before the aging heat treatment step [step 9], an additional cold rolling step [step 12] is further performed, and the copper alloy sheet material according to the above (V). Manufacturing method.

The copper alloy sheet of the present invention contains 0.3 to 2.5 mass% of Co and 0.1 to 0.7 mass% of Si, and further contains 0.05 to 1.0 mass of Cr, if necessary. %, 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 %, An alloy containing 0.01 to 0.15% by mass of Zn and 0.01 to 0.15% by mass of Zr, and at least one optional additive component selected from the group consisting of Cu and unavoidable impurities in the balance. A copper alloy sheet having a composition, and a crystal orientation analysis performed by an electron backscattering diffraction (EBSD) method on a longitudinal section parallel to the rolling direction of the copper alloy sheet has a reliability index (CI value) of 0. An area ratio of the measurement spot areas of 2 or less to all the measurement spot areas is 40% or less, and a pair of surface layer portions each including both surfaces of the plate having the vertical cross section and a pair of surface layer portions. divided into a central portion is positioned sandwiched, the average value of the reliability index of the surface layer portion of the pair (CI value) and CI _S, the average value of the reliability index of the central portion (CI value) CI _C when the ratio of CI _S for CI _{C (CI} S / CI _C ratio), by 0.8 to 2.0, which has a higher conductivity than Cu-Ni-Si alloy, Excellent bending workability and high strength can both be achieved at a high level.

Further, in the method for producing a copper alloy sheet according to the present invention, a copper alloy material having an alloy composition substantially the same as the alloy composition of the above copper alloy sheet is cast into a step [step 1] and a first chamfering step [step 2]. , Homogenizing heat treatment step [step 3], hot rolling step [step 4], cooling step [step 5], second chamfering step [step 6], first cold rolling step [step 7], solution heat treatment The step [step 8], the aging heat treatment step [step 9], the second cold rolling step [step 10] and the annealing step [step 11] are sequentially performed, and the temperature rising rate in the homogenization heat treatment step [step 3] is set to 10 ~110°C/sec and a holding temperature of 950 to 1250°C, the cooling start temperature in the surface layer portion of the plate material in the cooling step [step 5] is 680 to 850°C, and the average cooling rate is 5 to 20°C/sec. In the aging heat treatment step [step 9], the ultimate temperature is 450 to 650° C. and the holding time is 500 to 20,000 seconds, and in the second cold rolling step [step 10], the working rate per pass is 10%. When the rolling roll diameter is R, the working amount is Δh, and the final plate thickness is h, the parameter M is represented by the following formula (1), and is 6 or more and 40 or less. According to the above, the above-mentioned copper alloy plate material can be manufactured.

FIG. 1 is a schematic diagram for explaining a method of obtaining a reliability index (CI value) by performing a crystal orientation analysis by an EBSD method on a copper alloy sheet material of the present invention in a longitudinal section parallel to the rolling direction. .. FIG. 2 is a scanning electron microscope showing the bending outer surface state of the bent portion after the W bending test was performed in the Goodway direction at r/t=0 for the two types of copper alloy sheet materials according to the embodiment of the present invention. It is a SEM photograph when observed using (SEM), when (a) is Example 12 (Rq=5.7 μm), (b) is Example 9 (Rq=3.0 μm). Indicate the case.

Hereinafter, preferred embodiments of the copper alloy sheet material of the present invention will be described in detail.
The copper alloy sheet according to the present invention is a copper alloy sheet containing Co in an amount of 0.3 to 2.5% by mass and Si in an amount of 0.1 to 0.7% by mass, with the balance being Cu and inevitable impurities. Therefore, in the crystal orientation analysis performed by the electron backscattering diffraction (EBSD) method on the longitudinal section parallel to the rolling direction of the copper alloy sheet material, the numerical value of the reliability index (CI value) is 0.2 or less. The area ratio is 40% or less, and the longitudinal section is divided into a pair of surface layer portions each including both surfaces of the plate material, and a central portion located between the pair of surface layer portions, the average value of the reliability index (CI value) of the surface layer portion of the pair and CI _S, the average value of the reliability index (CI value) of the central portion when the CI _C, the CI _S for CI _C The ratio (CI _S /CI _C ratio) is 0.8 or more and 2.0 or less.

(I) Composition of Copper Alloy Sheet Material First, the reason for limiting the composition of the copper alloy sheet material of the present invention will be described.
The copper alloy sheet material of the present invention contains 0.3 to 2.5 mass% of Co and 0.1 to 0.7 mass% of Si.

<Co: 0.3 to 2.5 mass%>
Co (cobalt) is finely precipitated in the mother phase (matrix) of Cu as a second phase particle consisting of a simple substance or a compound with Si, for example, in a size of about 50 to 500 nm. It is an important component which has effects of precipitation hardening by suppressing dislocation movement, further suppressing grain growth to increase material strength by refining crystal grains, and improving bending workability. In order to exert such an effect, it is necessary that the Co content is 0.3% by mass or more. Further, Co has a smaller decrease rate of conductivity when it forms a solid solution than Ni, but when the Co content exceeds 2.5 mass %, the decrease in conductivity becomes remarkable and exceeds 50% IACS. Therefore, the Co content needs to be 2.5 mass% or less. For example, in the case of a general Cu-Ni-Si alloy (Cu-2.3 mass% Ni-0.65 mass% Si), the conductivity is about 38%IACS, but the Co content is 0.3. With the copper alloy sheet material of the present invention in the range of up to 2.5% by mass, a high numerical value is obtained in which the electrical conductivity exceeds 50% IACS. Further, the tensile strength of the copper alloy sheet material of the present invention depends on the manufacturing conditions, but by adopting specific manufacturing conditions, about 600 MPa can be obtained after aging precipitation, and a copper alloy made of a Cu-Ni-Si-based alloy High strength equivalent to plate material can be obtained. The Co content is preferably in the range of 0.8 to 1.6 mass% in order to satisfy both properties of tensile strength and conductivity in a well-balanced manner. Therefore, the Co content is set in the range of 0.3 to 2.5 mass %.

<Si: 0.1 to 0.7 mass%>
Si (silicon) finely precipitates in the Cu mother phase (matrix) as precipitates of second-phase particles composed of a compound together with Co, Cr, etc., and these precipitates suppress dislocation movement to cause precipitation hardening. Further, it is an important component having an action of suppressing grain growth and increasing the material strength by refining the crystal grains. In order to exert such an effect, the Si content needs to be 0.1% by mass or more. Further, when the Si content exceeds 0.7 mass %, the conductivity is remarkably lowered and the conductivity exceeding 50% IACS cannot be obtained. Therefore, the Si content is 0.7 mass% or less. There is a need to. Therefore, the Si content is set to the range of 0.1 to 0.7 mass %. The Si content is preferably in the range of 0.2 to 0.5 mass% in order to satisfy both properties of tensile strength and conductivity in a well-balanced manner.

<Optional additive components>
The copper alloy sheet material of the present invention contains Co and Si as essential essential contained components, and further contains 0.05 to 1.0 mass% of Cr and 0.05 to 0% of Ni as optional sub-additive components. 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 0.01 to 0.15 It may contain at least one optional additive component selected from the group consisting of mass% and Zr of 0.01 to 0.15 mass %.

(Cr: 0.05 to 1.0 mass%)
Cr (chromium) is finely precipitated as a compound or a simple substance in the matrix of Cu as a compound or a simple substance in the form of a precipitate having a size of, for example, about 50 to 500 nm, and this precipitate suppresses dislocation movement. It is a component that has the effect of precipitation hardening and further increasing the material strength by suppressing grain growth and refining the crystal grains, and also improving bendability. In order to exert this effect, the Cr content is preferably 0.05% by mass or more. Further, when the Cr content is 1.0% by mass or less, the rate of decrease in conductivity is small and the conductivity over 50% IACS tends to be obtained. Therefore, the Cr content is preferably 0.05 to 1.0% by mass.

(Ni: 0.05 to 0.7 mass%)
Ni (nickel) is finely precipitated as a compound or simple substance in the matrix of Cu (matrix) in the form of a precipitate having a size of, for example, about 50 to 500 nm, and this precipitate suppresses dislocation movement. It is a component which has effects of precipitation hardening, further suppressing grain growth, increasing the material strength by refining the crystal grains, and improving bending workability. To exert this effect, the Ni content is preferably 0.05% by mass or more. Further, when the Ni content is 0.7% by mass or less, the rate of decrease in conductivity is small, and a conductivity over 50% IACS tends to be obtained. Therefore, the Ni content is preferably 0.05 to 0.7 mass %.

(Fe: 0.02 to 0.5 mass%)
Fe (iron) 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 mass% or more. Further, if the Fe content is more than 0.5% by mass, not only the improvement effect cannot be expected, but also the conductivity tends to decrease. Therefore, the Fe content is preferably 0.02 to 0.5 mass %.

(Mg: 0.01 to 0.3 mass%)
Mg (magnesium) is a component having an action of improving stress relaxation resistance. In order to exert such an effect, the Mg content is preferably 0.01% by mass or more. If the Mg content is more than 0.3% by mass, the conductivity tends to decrease. Therefore, the Mg content is preferably 0.01 to 0.3 mass %.

(Mn: 0.01 to 0.5 mass%)
Mn (manganese) forms a solid solution in the parent phase to improve the rolling workability, suppresses the rapid development of grain boundary reaction type precipitation, and controls the discontinuous precipitation cell structure generated by grain boundary reaction type precipitation. It is a component that has an enabling effect. In order to exert such an effect, the Mn content is preferably 0.01% by mass or more. Further, if the Mn content is more than 0.5% by mass, not only the improvement effect cannot be expected, but also the conductivity may decrease and the bendability may deteriorate. Therefore, the Mn content is preferably 0.01 to 0.5 mass %.

(Zn: 0.01 to 0.15 mass%)
Zn (zinc) 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. Further, if the Zn content is more than 0.15 mass %, the conductivity tends to decrease. Therefore, the Zn content is preferably 0.01 to 0.15 mass %.

(Zr: 0.01 to 0.15 mass%)
Zr (zirconium) is a component mainly having a function of refining crystal grains to improve strength and bending workability. In order to exert such an effect, the Zr content is preferably 0.01 mass or more. Further, if the Zr content is more than 0.15 mass %, a compound is formed, and the conductivity and the press punching workability tend to be remarkably lowered. Therefore, the Zr content is preferably 0.01 to 0.15% by mass.

(Total content of optional additives: 1.5 mass% or less)
When two or more optional additive components selected from the group consisting of Cr, Ni, Fe, Mg, Mn, Zn and Zr described above are contained, the total content of the optional additive components should be 1.5% by mass or less. Preferably. This is because, if the total content of the optional additional components is 1.5% by mass or less, the press punching workability and the conductivity will not be significantly reduced.

<Remainder: Cu and inevitable impurities>
In addition to the above essential components and optional additives, the balance consists of Cu (copper) and unavoidable impurities. The term "unavoidable impurities" as used herein refers generally to metal products, which are present in the raw materials and are inevitably mixed in the manufacturing process. It is an allowable impurity because it does not affect the product characteristics. Examples of the components that can be cited as the inevitable impurities include silver (Ag), tin (Sn), oxygen (O), and the like. The upper limit of the content of these components may be 0.05 mass% for each of the above components, and 0.20 mass% for the total amount of the above components.

(II) Reliability index CI of the EBSD method
The copper alloy sheet of the present invention has a reliability index (CI value) of 0.2 or less in the crystal orientation analysis performed by the electron backscattering diffraction (EBSD) method on the longitudinal section parallel to the rolling direction of the copper alloy sheet. The area ratio of the measurement spot area occupying in all the measurement spot areas is 40% or less, and the longitudinal section is formed into a pair of surface layer portions including both surfaces of the plate material and a pair of surface layer portions. was divided into a central portion positioned pinched, the average value of the reliability index (CI value) of the surface layer portion of the pair and CI _S, the average value of the reliability index (CI value) of the central portion when to the CI _C, the ratio of the CI _S for _{CI C (CI S / CI C} ) is 0.8 to 2.0.

The present inventor has conducted a study to make excellent bending workability and high strength compatible with each other at a high level by using a Cu—Co—Si alloy having higher conductivity than the Cu—Ni—Si alloy. It was found that the bending workability deteriorates as the strain introduced into the rolled plate material, particularly the surface layer portion of the plate material, increases.

Further, when a method for evaluating the magnitude of strain introduced into this plate material was further studied, a crystal obtained by electron backscattering diffraction (EBSD) was applied to a longitudinal section parallel to the rolling direction of the copper alloy plate material. In the azimuth analysis, the reliability index CI in each measurement spot area is calculated, and the area ratio of the measurement spot area having a reliability index (CI value) of 0.2 or less in all the measurement spot areas is 40% or less. In some cases, it has been found that a rolling structure having a relatively small strain is maintained, and bending workability tends to be ensured without deterioration. However, even when the area ratio is 40% or less, a high level of bending workability may not be obtained in some cases.

Therefore, the present inventor has further conducted intensive was conducted study, in the vertical section, the average CI _S reliability index of the surface layer portion (CI value), the average value of the reliability index of the central portion (CI value) by the ratio of CI _S a _(CI S / CI _C ratio) of 0.8 to 2.0 for CI _C, it made it possible to achieve both excellent bending property and high strength at a high level. When the CI S _/ CI _C ratio is less than 0.8, the surface distortion surface layer of the sheet material is compared to the central portion (inside) is too large, the proportion of bending workability for tensile strength of the plate becomes lower Therefore, it becomes impossible to achieve a good balance between tensile strength and bending workability. Also, the when the CI S _/ CI _C ratio is greater than 2.0, although the bending ratio of workability is increased relative to the tensile strength of the plate material, uneven distribution of strain in the center portion of the plate (inside) is increased This is because there is a high possibility that variations in shape will occur during press working. _Therefore, CI S / CI _C ratio of 0.8 to 2.0, preferably 1.0 to 1.8.

The calculation method of the reliability index (CI value) is as follows. The crystal orientation measured by the electron backscatter diffraction (EBSD) method is used for each measurement spot area (spot size: 0.5 μm×0.5 μm) by using analysis software. ) Was calculated. A longitudinal section parallel to the rolling direction of the copper alloy sheet, in other words, a section perpendicular to the rolling direction of the copper alloy sheet, is mechanically polished with water-resistant abrasive paper and diamond abrasive before measurement by the EBSD method. After that, finish polishing was performed using a colloidal silica solution. Then, the measurement was performed by the EBSD method 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. The scan step was performed in 0.1 μm steps in order to measure fine crystal grains. In the analysis, an inverse pole figure IPF (Inverse Pole Figure) was confirmed by the analysis based on the EBSD measurement result of 64×10 ⁴ μm ² . The electron beam was generated by thermoelectrons from the W filament of the scanning electron microscope. The probe diameter at the time of measurement is about 0.015 μm. As the measuring device for the EBSD method, OIM5.0 (trade name) manufactured by TSL Solutions Co., Ltd. was used.

FIG. 1 illustrates a method for obtaining a reliability index (CI value) by performing crystal orientation analysis (mapping) by the EBSD method on a copper alloy sheet material 10 of the present invention in a longitudinal section parallel to the rolling direction. It is a schematic diagram. As shown in FIG. 1, each measurement spot region is scanned in the longitudinal direction parallel to the rolling direction with an electron beam from one surface layer portion 11a through the central portion 12 to the other surface layer portion 11b, and all the scanning spots are scanned. The area ratio occupied by the measurement spot region having a reliability index (CI value) of 0.2 or less was calculated with respect to the measurement spot region.

Further, the surface layer portions 11a and 11b of the plate material in the present invention mean plate material portions corresponding to ⅛ of the plate thickness respectively from both sides of the plate material, and the central portion 12 is a pair of surface layer portions 11a. And 11b means a sandwiched plate material portion.

Further, the average value CI _S reliability index of the surface layer portion of the plate member (CI value), method of calculating the average value CI _C reliability index of the central portion of the plate member (CI value), the thickness direction (FIG plate material 10 vertical lines) are drawn on the longitudinal section of the plate material at predetermined intervals (for example, 20 μm intervals), and from the distribution of the CI value on each line, the surface layer portion and the central portion of the plate material are respectively extracted. The average value of the reliability index (CI value) was calculated. For the measurement, 10 fields of view were measured for each strip, and the average value was used as the value. The reliability index (CI value) of this EBSD method is a value measured by the analysis software OIM Analysis of the EBSD device, and the crystal pattern of the evaluation/analysis result is not good, that is, the processed structure is The greater the distortion associated with, the lower the CI value.

(III) Tensile Strength In the present invention, the tensile strength when pulled in parallel with the rolling direction is preferably 600 MPa or more. The measurement of the tensile strength was performed on three test pieces of No. 13B specified in JIS Z2241:2011 cut out from the rolling parallel direction, and the tensile strength was an average value of the tensile strengths obtained from the three test pieces. And

(IV) Conductivity (EC)
The copper alloy sheet material of the present invention preferably has a conductivity of more than 50% IACS. The electrical conductivity can be calculated from the numerical value of the specific resistance measured by the four-terminal method in a constant temperature bath kept at 20°C (±0.5°C).

(V) root mean square roughness Rq
The copper alloy sheet material of the present invention has a root mean square roughness on the bending outer surface of the bending portion after a W bending test according to the Japan Copper and Brass Association (JCBA) T307:2007 in the Goodway direction at r/t=0. It is preferable that the thickness Rq is 7.0 μm or less. This is because when the root mean square roughness Rq is 7.0 μm or less, the surface roughness of the bending outer surface of the bending portion is sufficiently small, and the bending workability tends to be good. Each test material was bent according to the test method of Japan Copper and Brass Association technical standard JCBA-T307:2007. A plurality of test pieces with a width of 10 mm and a length of 30 mm were sampled from each test material so that the rolling direction and the longitudinal direction of the test pieces were parallel, and a W-shaped jig with a bending angle of 90 degrees and a bending radius of 0 mm. Was used to perform a W bending test. Then, with respect to the outer peripheral portion of the bent portion, unevenness of the bent surface of the 90°W bending test piece was measured with a laser microscope at a pitch of 0.1 μm. The root mean square roughness Rq is calculated in accordance with JIS B0601:2013 by substituting it into the following equation (2). The small surface roughness of the bent portion indicates that the bending workability of the material is good.

However, 1 is a reference length.

(VI) Method of Manufacturing Copper Alloy Sheet Material According to One Embodiment of the Present Invention The copper alloy sheet material described above can be realized by controlling the alloy composition and the manufacturing process in combination. Hereinafter, a suitable method for producing the copper alloy sheet of the present invention will be described.

In the method for manufacturing a copper alloy sheet according to the embodiment of the present invention, a copper alloy material having substantially the same alloy composition as the above-described alloy composition of the copper alloy sheet is cast in the step [step 1], Chamfering step [step 2], homogenizing heat treatment step [step 3], hot rolling step [step 4], water cooling step [step 5], second chamfering 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 annealing step [step 11] are sequentially performed, and the homogenization heat treatment step [step 3 ], the holding temperature is 950 to 1250° C., the cooling start temperature in the surface layer part of the plate material in the cooling step [step 5] is 680 to 850° C., and the average cooling rate is 5 To 20° C./sec, the temperature reached in the aging heat treatment step [step 9] is 450 to 650° C., the holding time is 500 to 20000 seconds, and the second cold rolling step [step 10] is 1 pass. When the processing rate per unit is 10% or more and 40% or less, and the rolling roll diameter is R, the processing amount is Δh, and the final plate thickness is h, the parameter M is represented by the following formula (1), It is 6 or more and 40 or less.
M={(R·Δh) ^0.5 }/h ··· (1)

In the method for producing a copper alloy sheet according to the present invention, in particular, the homogenizing heat treatment step [step 3] and the aging heat treatment step [step 9] are controlled, and the cooling step [after the hot rolling step [step 4]] is performed. 5] and controlling the second (final) cold rolling step [step 10]. That is, in the homogenizing heat treatment step [step 3], the temperature rising rate is 10 to 110° C./sec and the holding temperature is 950 to 1250° C., and in the cooling step [step 5] performed after the hot rolling step [step 4]. The cooling start temperature in the surface layer part of the plate material is 680 to 850° C., the average cooling rate is 5 to 20° C./sec, and the ultimate temperature in the aging heat treatment step [step 9] is 450 to 650° C. and the holding time is 500 to 20,000. Second, and in the second (final) cold rolling step [Step 10], the working rate per pass is 10% or more and 40% or less, and M={(R·Δh) ^0.5 }/ It is necessary to set the parameter M represented by h to 6 or more and 40 or less.

(I) Casting process [Process 1]
In the casting step, a copper alloy material having the alloy components shown in Table 1 is melted in a high-frequency melting furnace in the air, and the ingot is cast into a predetermined shape (for example, thickness 300 mm, width 500 mm, length 3000 mm). To manufacture. The alloy composition of the copper alloy material may not always completely match the alloy composition of the copper alloy sheet material produced by adhering to the melting furnace or volatilizing depending on the additive components in each step of production. However, it has an alloy composition substantially the same as that of the copper alloy sheet.

(Ii) First surface cutting step [Step 2]
The first chamfering step removes the oxide film formed on the surface of the ingot obtained in the casting step (step 1) in which the copper alloy material is melted, so that both sides of the ingot have a thickness of 0.5 mm or more. It is a process of scraping off just that much.

(Iii) Homogenization heat treatment step [Step 3]
In the homogenizing heat treatment step, the temperature rising rate is 10 to 110° C./sec and the holding temperature is 950 to 1250° C. If the temperature rising rate in the homogenizing heat treatment step is less than 10°C/sec or more than 110°C/sec or the holding temperature is less than 950°C, the solid solution of the crystallized product produced during casting becomes insufficient, and the product is produced. In addition, it becomes impossible to obtain a satisfactory level of strength and conductivity in the copper alloy sheet material. On the other hand, if the holding temperature in the homogenizing heat treatment step exceeds 1250° C., the vicinity of the crystal grain boundaries is partially in the liquid phase, cracks are likely to occur during hot rolling, and production may not be possible in some cases.

(Iv) Hot rolling process [Process 4]
The hot rolling step is a step in which the ingot immediately after the homogenizing heat treatment is hot rolled to a predetermined thickness to produce a hot rolled sheet. The hot rolling conditions are, for example, preferably a rolling temperature of 600 to 1100° C., a rolling frequency of 4 or more, and a total rolling rate of 60% or more. The term "rolling rate" as used herein means a value obtained 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 to express it as a percentage. That is, it is represented by the following formula.
[Rolling rate]={([Cross sectional area before rolling]−[Cross sectional area after rolling])/[Cross sectional area before rolling]}×100(%)

(V) Cooling process [Process 5]
The cooling step is also performed after the hot rolling step (step 4), and is a surface layer portion (a plate material corresponding to 1/8 of the plate thickness from the surface of the plate material) of the plate material (hot rolled plate) in the cooling step. It is necessary to set the cooling start temperature in (part) to 680 to 850°C and the average cooling rate to 5 to 20°C/sec. If the cooling start temperature is lower than 680° C. or the average cooling rate is lower than 5° C./sec, coarse precipitation of solute elements will proceed during cooling, and the copper alloy sheet produced will not have satisfactory strength and electrical conductivity. Because. On the other hand, if the cooling start temperature exceeds 850° C. or the average cooling rate exceeds 20° C./sec, the formation of the rolling structure becomes insufficient, which adversely affects the bendability after the final step. In addition, if the average cooling rate exceeds 20° C./sec, the precipitation of the surface is too small, the crystal grain coarsening of the surface progresses in the solution treatment step, and strain easily accumulates, and the target CI value is obtained. Is not satisfied, and bending workability deteriorates.

(Vi) Second chamfering process [process 6]
The second chamfering step is a step of scraping both the front and back surfaces of the hot rolled material by a thickness of 0.5 mm or more in order to remove the oxide film on the surface of the hot rolled material.

(Vii) First cold rolling step [Step 7]
The first cold rolling step is a step of producing a cold rolled sheet by performing cold rolling until a predetermined thickness is obtained after the second chamfering step. It is preferable that the cold rolling condition is, for example, two or more rolling cycles and a total rolling work rate of 50% or more.

(Viii) Solution heat treatment step [Step 8]
The solution heat treatment step is a step of performing heat treatment at a temperature rising rate of 1 to 150° C./second, an ultimate temperature of 800 to 1000° C., a holding time of 1 to 300 seconds, and a cooling rate of 1 to 200° C./second.

(Ix) Additional cold rolling process [Process 12]
The additional cold rolling step is a step that is optionally performed after the solution heat treatment step [step 8] and before the aging heat treatment step [step 9], and is not an essential step. By performing the additional cold rolling step, the tensile strength can be further improved without impairing the bending workability. It is preferable that the rolling conditions are, for example, one or more rolling cycles and a total rolling rate of 10 to 70%.

(X) Aging heat treatment process [Process 9]
In the aging heat treatment step, it is necessary that the ultimate temperature is 450 to 650° C. and the holding time is 500 to 20,000 seconds. When the ultimate temperature is less than 450° C. or the holding time is less than 500 seconds, the amount of aging precipitation is insufficient and the strength and conductivity are insufficient. On the other hand, if the reached temperature exceeds 650° C. or exceeds 20,000 seconds, coarsening of precipitates occurs and the strength becomes insufficient.

(Xi) Second (final) cold rolling step [Step 10]
In the second (final) cold rolling step, the rolling rate per pass is set to 10% or more and 40% or less, and the parameter M represented by M={(R·Δh) ^0.5 }/h is set. It is necessary to be 6 or more and 40 or less. If the rolling rate per pass is less than 10%, the amount of work hardening is small and sufficient tensile strength cannot be obtained, and if the rolling rate per pass exceeds 40%, a large shearing force is applied to the entire plate material. This is because distortion occurs and bending workability deteriorates. Also, if the parameter M is less than 6, strain accumulates on the surface and the target CI value distribution is not satisfied. On the other hand, if the parameter M exceeds 40, the load on the rolling equipment becomes extremely large, and Because it is not the target. As the second cold rolling condition, for example, it is preferable that the number of times of rolling is 2 or more and the total rolling rate is 10% or more. The parameter M becomes smaller as R and Δh become smaller or h becomes larger. In particular, as a significant effect on the CI value, when R becomes small, the contact length between the material and the roll is reduced, and only the vicinity of the surface is sheared, so that the strain amount becomes relatively high and the inside is uniform. CI _S / CI _C for not distorted state tends to be low. On the other hand, the parameter M increases as R or Δh increases or h decreases. In particular, as a significant effect on the CI value, Δh, that is, when the processing amount increases, the area ratio at which the CI value becomes 0.2 or less decreases, and the workability tends to decrease. Therefore, the rolling roll diameter R, by properly setting the etching amount Δh and final thickness h, CI value, CI _S / CI _C, more it is possible to control the strength and bending workability.

(Xii) Annealing process [Process 11]
The annealing step is a heat treatment performed after the second (final) cold rolling step. The annealing conditions are preferably, for example, an ultimate temperature of 200 to 600° C. and a holding time of 1 to 3600 seconds.

(VII) Uses of Copper Alloy Plate Material The copper alloy plate material of the present invention is suitable for use in, for example, lead frames, connectors, terminal materials, relays, switches, sockets for in-vehicle parts and electric/electronic devices.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and includes all aspects included in the concept of the present invention and the scope of the claims, and various modifications within the scope of the present invention. Can be modified to

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

(Invention Examples 1 to 16 and Comparative Examples 1 to 9)
The oxide film formed on the surface of the ingot (size: (thickness 300 mm, width 500 mm, length 3000 mm)) obtained in the casting step (step 1) for melting the copper alloy material having the alloy composition shown in Table 1 is removed. For this purpose, after performing the first surface-polishing step (step 2) in which both the front and back surfaces are each cut by a thickness of 0.5 mm or more, the homogenization heat-treatment step (step 3) and then the hot rolling step (step 4) under the conditions of a rolling temperature of 600 to 1100° C., a rolling number of 4 times or more, and a total working rate of 60% or more. The cooling step (step 5) was performed under the conditions of the cooling start temperature and the cooling rate, and then both front and back surfaces of the hot rolled material were shaved by a thickness of 0.5 mm or more in order to remove the oxide film on the surface. After performing the second chamfering step (step 6), the first cold rolling step (step 7) is performed under the condition that the number of rolling times is 2 times or more and the total working rate is 50% or more, and then the temperature rising rate is 1 to The solution heat treatment step (step 8) is performed under the conditions of 150° C./second, ultimate temperature of 800 to 1000° C., holding time of 1 to 300 seconds, and cooling rate of 1 to 200° C./second. After performing the aging heat treatment step (step 9) under the condition of the holding time, under the conditions of the rolling rate of 2 times or more and the total working rate of 5% or more so that the processing rate per pass and the parameter M shown in Table 2 are obtained. The second cold rolling step (step 10) was performed at that temperature, and then the annealing step (step 11) was performed at an ultimate temperature of 200 to 600° C. and a holding time of 1 to 3600 seconds. , 6 to 8 and 12, and Comparative Examples 1, 3, 8 and 9, after the solution heat treatment step and before the aging heat treatment step, an additional cold rolling step (step 12) was performed at a total rolling work rate of 5 to It was further performed at 70% In this way, the copper alloy sheet material of the present invention was produced.

[Various measurement and evaluation methods]
The following characteristic evaluations were performed using the copper alloy sheet materials according to the present invention example and the comparative example. The evaluation conditions for each characteristic are as follows.

[1] Method for measuring composition of copper alloy sheet material The alloy composition was measured by ICP analysis.

[2] EBSD measurement method After mechanically polishing a vertical section parallel to the rolling direction of each of the prepared test materials (copper alloy plate materials) with water-resistant abrasive paper and diamond abrasive grains, a colloidal silica solution is used. Finish polishing was performed. Then, the measurement was performed by the EBSD method 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. The scan step was performed in 0.1 μm steps in order to measure fine crystal grains. In the analysis, an inverse pole figure IPF (Inverse Pole Figure) was confirmed by the analysis from the EBSD measurement result of 64×10 ⁴ μm ² . The electron beam was generated by thermoelectrons from the W filament of the scanning electron microscope. The probe diameter at the time of measurement is about 0.015 μm. As the measuring device for the EBSD method, OIM5.0 (trade name) manufactured by TSL Solutions Co., Ltd. was used.

[3] Method of measuring reliability index CI The area ratio of the measurement spot area having a reliability index (CI value) of 0.2 or less to the entire measurement spot area is parallel to the rolling direction as shown in FIG. In a vertical cross section, an electron beam was scanned from one surface layer portion 11a through the central portion 12 to the other surface layer portion 11b, and calculation was performed from all the scanned measurement spot regions. Further, the average value CI _S reliability index of the surface layer portion of the sample material (CI value), method of calculating the average value CI _C reliability index of the central portion of the test material (CI value), the sheet thickness Draw 10 lines that scan the vertical cross section of the plate at predetermined intervals (for example, 20 μm intervals) in the vertical direction (vertical direction in FIG. 1), and from the distribution of the CI value on each line, determine the surface layer of the plate. The average value of each reliability index (CI value) in the central part was obtained. For the measurement, 10 fields of view were measured for each strip, and the average value was used as the value. The reliability index (CI value) of the EBSD method is a value measured by the analysis software OIM Analysis of the EBSD device.

[4] Tensile Strength Tensile strength was measured with three test pieces of No. 13B specified in JIS Z2241:2011 cut out from the rolling parallel direction, and the tensile strength was obtained from the three test pieces. The average value of tensile strength was used. In this example, a tensile strength of 600 MPa or more was regarded as a pass level.

[5] Method of measuring conductivity (EC) The conductivity can be calculated from the numerical value of the specific resistance measured by the four probe method in a constant temperature bath kept at 20°C (±0.5°C). The distance between the terminals was 100 mm. In the present embodiment, the case where the conductivity exceeds 50% IACS was regarded as the pass level.

[6] Method of Measuring Root Mean Square Roughness Rq Each of the test materials was bent according to the test method of Japan Copper and Brass Association Technical Standard JCBA-T307:2007. And 10 mm wide x 30 mm long test pieces were sampled from each test material so that the longitudinal direction of the test pieces and the longitudinal direction of the test pieces were parallel, and a W-shaped jig with a bending angle of 90 degrees and a bending radius of 0 mm was used. , W bending test was performed. Then, with respect to the outer peripheral portion of the bent portion, the unevenness of the bent surface of the 90°W bending test piece was measured with a laser microscope at a pitch of 0.1 μm. The root mean square roughness Rq was calculated according to JIS B0601:2013 by substituting it into the following equation (2). In this example, the case where the root mean square roughness Rq was 7.0 μm or less was regarded as the pass level.

From the results of Tables 1 to 3, all of the copper alloy sheet materials of Examples 1 to 16 of the present invention have an alloy composition within the appropriate range of the present invention and a measurement spot whose reliability index (CI value) is 0.2 or less. region, the area ratio to the total measurement spot area is not more than 40%, and CI for S _/ CI _C ratio is 0.8 to 2.0, processability balance performance and tensile bending strength is superior And the conductivity was more than 50% IACS.

On the other hand, none of the copper alloy sheet of Comparative Example 1-9, the alloy composition, since at least one of the area ratio and CI S _/ CI _C ratio is outside the appropriate range of the present invention, at least the bending workability and tensile strength One did not reach the passing level.

10 Copper alloy plate material 11a, 11b Surface layer part of copper alloy plate material 12 Central part of copper alloy plate material

Claims (6)

1. A copper alloy plate material containing 0.3 to 2.5% by mass of Co and 0.1 to 0.7% by mass of Si, with the balance being Cu and unavoidable impurities.
   A crystal orientation analysis performed by an electron backscattering diffraction (EBSD) method on a longitudinal section parallel to the rolling direction of the copper alloy sheet material is
   The area ratio of the measurement spot area having a reliability index (CI value) of 0.2 or less to all the measurement spot areas is 40% or less, and
   The vertical cross section is divided into a pair of surface layer portions each including both surfaces of the plate material and a central portion located between the pair of surface layer portions, and the reliability index of the pair of surface layer portions ( when the average value of the CI value) and CI _S, the average value of the reliability index (CI value) of the central portion and CI _C, the ratio of the CI _S for CI _{C (CI} S / CI _C ratio), A copper alloy plate material, which is 0.8 or more and 2.0 or less.
2. Contains 0.3 to 2.5% by mass of Co and 0.1 to 0.7% by mass of Si, further contains 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% by mass, Mg 0.01 to 0.3% by mass, Mn 0.01 to 0.5% by mass, Zn 0.01 to 0.15% by mass and Zr Is a copper alloy sheet containing at least one optional additive component selected from the group consisting of 0.01 to 0.15% by mass, the balance being Cu and unavoidable impurities.
   A crystal orientation analysis performed by an electron backscattering diffraction (EBSD) method on a longitudinal section parallel to the longitudinal direction of the copper alloy plate material is as follows.
   The area ratio of the measurement spot area having a reliability index (CI value) of 0.2 or less to all the measurement spot areas is 40% or less, and
   The vertical cross section is divided into a pair of surface layer portions each including both surfaces of the plate material and a central portion located between the pair of surface layer portions, and the reliability index of the pair of surface layer portions ( when the average value of the CI value) and CI _S, the average value of the reliability index (CI value) of the central portion and CI _C, the ratio of the CI _S for CI _{C (CI} S / CI _C ratio), A copper alloy plate material, which is 0.8 or more and 2.0 or less.
3. The copper alloy sheet material according to claim 2, wherein the total amount of the optional additive components is 1.5% by mass or less.
4. The tensile strength when stretched parallel to the rolling direction is 600 MPa or more,
   Conductivity is above 50% IACS, and
   The root mean square roughness Rq of the bent outer surface of the bent portion was 7.0 μm or less after the W bending test according to the Japan Copper and Brass Association (JCBA) T307:2007 was performed at r/t=0 in the Goodway direction. The copper alloy sheet material according to any one of claims 1 to 3.
5. A method for manufacturing the copper alloy sheet according to any one of claims 1 to 4,
   A copper alloy material having an alloy composition that is substantially the same as the alloy composition of the copper alloy sheet material is added to a casting step [step 1], a first chamfering step [step 2], a homogenizing heat treatment step [step 3], and a hot work. Rolling process [process 4], cooling process [process 5], second chamfering process [process 6], first cold rolling process [process 7], solution heat treatment process [process 8], aging heat treatment process [process 9] ], the second cold rolling step [step 10] and the annealing step [step 11] are sequentially performed,
   In the homogenizing heat treatment step [step 3], the temperature rising rate is 10 to 110° C./sec and the holding temperature is 950 to 1250° C.
   In the cooling step [step 5], the cooling start temperature in the surface layer portion of the plate material is 680 to 850° C., and the average cooling rate is 5 to 20° C./sec.
   In the aging heat treatment step [step 9], the ultimate temperature is 450 to 650° C., the holding time is 500 to 20,000 seconds, and
   In the second cold rolling step [Step 10], when the working rate per pass is 10% or more and 40% or less, and the rolling roll diameter is R, the working amount is Δh, and the final plate thickness is h. The parameter M is represented by the following equation (1), and is 6 or more and 40 or less, the manufacturing method of the copper alloy sheet material.
   M={(R·Δh) ^0.5 }/h ··· (1)
6. The method for producing a copper alloy sheet according to claim 5, further comprising an additional cold rolling step [step 12] after the solution heat treatment step [step 8] and before the aging heat treatment step [step 9].

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