CN106460099B

CN106460099B - Copper alloy sheet material, connector made of copper alloy sheet material, and method for manufacturing copper alloy sheet material

Info

Publication number: CN106460099B
Application number: CN201580028223.1A
Authority: CN
Inventors: 矶松岳己; 樋口优
Original assignee: Furukawa Electric Co Ltd
Current assignee: Furukawa Electric Co Ltd
Priority date: 2014-05-30
Filing date: 2015-05-29
Publication date: 2020-03-17
Anticipated expiration: 2035-05-29
Also published as: JP5972484B2; JPWO2015182776A1; KR101935987B1; WO2015182776A1; KR20170012282A; CN106460099A

Abstract

The invention provides a copper alloy material, which is a copper alloy plate material with the following composition: 1.0 to 6.0 mass% of Ni, 0.2 to 2.0 mass% of Si, and 0.000 to 3.000 mass% in total of at least 1 selected from the group consisting of B, Mg, P, Cr, Mn, Fe, Co, Zn, Zr, Ag and Sn, the balance being copper and unavoidable impurities, wherein the work hardening index n in the direction parallel to the Rolling Direction (RD)_RDIs 0.010 to 0.150, said n_RDWork hardening index n in the direction perpendicular to rolling (TD)_TDRatio n of_RD/n_TD0.500 to 1.500, and 5.0 to 30.0% of an average Sa of an area ratio S (D) of crystal grains having a deviation angle of 15 DEG or less from Cube orientation {001} < 100 > in a plane parallel to the surface of the rolling plane at a depth D of the copper alloy sheet, which is excellent in bending workability, has excellent strength, and has a low bending modulus as spring characteristics after bending, and the anisotropy of each of the bending workability, strength, and bending modulus in the rolling direction and the direction perpendicular to the rolling direction is small.

Description

Copper alloy sheet material, connector made of copper alloy sheet material, and method for manufacturing copper alloy sheet material

Technical Field

The invention relates to a copper alloy plate and a manufacturing method thereof. In particular, the present invention relates to a copper alloy sheet material excellent in bending workability, strength, and spring characteristics after bending, and a method for producing the same, and the copper alloy sheet material is suitable for use in lead frames, connectors, terminal materials, relays, switches, sockets, and the like for vehicle-mounted components and electric/electronic devices.

Background

The characteristic items required for copper alloy sheet materials used for applications such as lead frames for vehicle-mounted parts and electrical/electronic devices, connectors, terminal materials, relays, switches, and sockets include electrical conductivity, proof stress (yield stress), tensile strength, and bending workability. In recent years, the required characteristics have been improved with the miniaturization, weight reduction, high functionality, high density mounting, and high temperature of the use environment of electric and electronic devices. In particular, in sheet materials of copper or copper alloys used for parts for vehicle mounting and parts for electric/electronic devices, the demand for thinner wall is increasing, and the required strength level is further increasing.

Further, as one of the characteristic items required for copper alloy materials used for electric/electronic devices and vehicle-mounted parts, low flexural modulus is required. In recent years, as connectors and vehicle-mounted components are miniaturized, dimensional accuracy of terminals and tolerance of press working have become strict. By reducing the coefficient of deflection of the material, the influence of dimensional variation on the contact pressure of the contact portion can be reduced, and thus the design becomes easy.

Further, materials used for components such as connectors, terminals, lead frames, relays, and switches constituting vehicle-mounted components and electric/electronic components are required to have high strength capable of withstanding stress applied during assembly or operation of the vehicle-mounted components and the electric/electronic devices.

Conventionally, as a material for electric/electronic devices, in addition to an iron-based material, a copper-based material such as phosphor bronze, red copper, and brass has been widely used. These alloys improve strength by a combination of solid solution strengthening of Sn and Zn and work hardening by cold working such as rolling and wire drawing. In this method, the electric conductivity is insufficient, and since high strength is obtained by cold working at a high rolling reduction, the bending workability and the stress relaxation resistance are insufficient.

As a strengthening method of a copper alloy, there is a precipitation strengthening method of precipitating a fine second phase in a material. In addition to improving strength, this strengthening method has the advantage of simultaneously improving electrical conductivity, and is therefore carried out in a large number of alloy systems. However, with the recent miniaturization of electrical/electronic devices and vehicle-mounted parts for automobiles, copper alloys are being subjected to bending with a smaller radius for higher strength materials, and copper alloy sheet materials having excellent bending workability are strongly required. Further, even in the case of a plate material having high strength, high elasticity and good bending workability, it is not preferable that the plate material has poor properties in the rolling parallel direction (RD, rolling direction) and the rolling perpendicular direction (TD, width direction), and it is important that the plate material exhibits good properties in any direction. In particular, when used as a subminiature terminal, it is important to perform microfabrication on a lead mold (ピン type) with a narrow width, and to exhibit good characteristics in both the rolling parallel direction and the rolling perpendicular direction. In conventional Cu-Ni-Si based copper alloys, the rolling reduction is increased to obtain a large work hardening in order to obtain a high strength. However, this method deteriorates the bending workability as described above, and it is difficult to achieve both high strength and good bending workability.

In recent years, with the miniaturization of the entire module and the densification of electric components, terminals for electric/electronic devices, connectors, terminals for mounting on vehicles, and the like have been bent to a smaller radius than ever before, and further processed into complicated shapes. In both cases where the axis of bending is perpendicular to the rolling direction (GW bending) and parallel to the rolling direction (BW bending), complicated processing with a small bending radius is added, and the spring characteristics (contact pressure, amount of deflection) after further processing must be uniform (according to design values). Conventionally, when a plate material of a corson alloy (Cu-Ni-Si alloy) is processed and used as a contact portion of a terminal, only processing in a specific direction (GW or BW) is performed. However, as described above, since the terminal is recently processed into a complicated shape, it is designed to add several GW bends and BW bends to 1 terminal. In this case, a conventional material having anisotropy in bending, strength, and work hardening index is cracked in either of the GW and BW bending, and cannot be used as a terminal or a connector. In addition, when the anisotropic material has anisotropy, the spring characteristics after the processing are also deviated by the bending direction, and the anisotropic material cannot be used as a terminal or a connector.

Conventionally, several solutions have been proposed to improve the bending workability by controlling the work hardening index and the crystal orientation. For example, patent document 1 proposes that in a Cu — Ni — Si alloy, the bending workability of GW and BW is improved by controlling the tensile strength, proof stress, uniform elongation, total elongation, and work hardening index in both the rolling parallel direction (LD) and the rolling perpendicular direction (TD). Further, patent document 2 proposes to improve the bending workability by controlling the crystal orientation and work hardening index of the Cu — Ni — Si based alloy. Patent document 3 proposes that strength and bending workability can be achieved by controlling the Cube orientation area ratio to 10% or more.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2010-031379

Patent document 2: japanese patent laid-open publication No. 2013-047360

Patent document 3: japanese patent application laid-open publication No. 2011-117034

Disclosure of Invention

Problems to be solved by the invention

In the invention described in patent document 1, by controlling the mechanical properties in the direction parallel to the rolling direction and the direction perpendicular to the rolling direction, excellent properties with a balanced strength and bending workability are obtained. However, there is no description about the control of crystal orientation and crystal grain size. In the invention described in patent document 2, strength and bending workability are both achieved by controlling the crystal orientation and the work hardening index. However, the control of the anisotropy in the rolling parallel direction and the rolling perpendicular direction was not performed, and the control of the respective crystal orientations was performed, but the distribution in the sheet thickness direction was not described. In patent document 3, the bending workability is improved by the aggregation of Cube orientation area ratios. However, the work hardening index was not controlled, and the anisotropy in both the rolling parallel direction and the rolling perpendicular direction was not controlled.

In view of the above-described problems of the prior art, an object of the present invention is to provide a copper alloy sheet material which is excellent in bending workability, has excellent strength, has a low bending modulus as a spring characteristic after bending, has low anisotropy in the rolling parallel direction and the rolling perpendicular direction of each of the bending workability, strength and bending modulus, and is suitable for a lead frame, a connector, a terminal material, and the like for high-quality electric/electronic equipment, a connector, a terminal material, and the like for automobile-mounted use, and the like, a connector, a terminal material, a relay, a switch, a socket, and the like for which complicated processing such as GW bending and BW bending can be performed on 1 part can be performed.

Means for solving the problems

The present inventors have made extensive studies on a copper alloy sheet material of a Cu — Ni — Si alloy, which has greatly improved bending workability and strength and is suitable for use in electric/electronic components or automotive vehicle-mounted components, and as a result, have found that there is a correlation between the work hardening index, bending workability, and strength and their anisotropy. Further, by appropriately controlling the relationship between the work hardening indexes in the parallel rolling direction and the perpendicular rolling direction of the plate material, the anisotropy in both bending work and strength can be reduced. Further, as a result of the investigation, it was found that the bending workability and the anisotropy thereof can be improved by appropriately controlling the texture. The present invention has been completed based on these findings.

That is, according to the present invention, the following means is provided.

(1) A copper alloy sheet material having a composition of: the copper alloy sheet material is characterized by containing 1.0-6.0 mass% of Ni and 0.2-2.0 mass% of Si, and at least 1 selected from the group consisting of B, Mg, P, Cr, Mn, Fe, Co, Zn, Zr, Ag and Sn in a total amount of 0.000-3.000 mass%, with the remainder being copper and unavoidable impurities (wherein the above B, Mg, P, Cr, Mn, Fe, Co, Zn, Zr, Ag and Sn may or may not contain any one or more of them, but may be any additive component),

work hardening index n in parallel direction to Rolling (RD)_RDIs 0.010 to 0.150,

work hardening index n in the direction parallel to the rolling_RDWork hardening index n in the direction perpendicular to rolling (TD)_TDRatio n of_RD/n_TDIs in the range of 0.500 to 1.500,

when the plate thickness of the copper alloy plate material is t, the depth of the copper alloy plate material in the plate thickness direction from the surface of a rolling surface is D, and the area ratio of crystal grains within a deviation angle of 15 DEG from Cube orientation {001} < 100 > in a plane parallel to the surface of the rolling surface at the depth D of the copper alloy plate material is S (D), the average Sa of S (D) in the plate thickness direction is 5.0-30.0%.

(2) The copper alloy sheet according to item (1), wherein the total of 0.005 to 3.000 mass% of at least 1 selected from the group consisting of B, Mg, P, Cr, Mn, Fe, Co, Zn, Zr, Ag and Sn is contained.

(3) The copper alloy sheet material according to the item (1) or (2), wherein a ratio a/b of an average grain diameter a in a direction parallel to rolling to an average grain diameter b in a direction perpendicular to rolling is 0.8 or more with respect to crystal grains of the base material.

(4) The copper base alloy sheet according to any one of (1) to (3), wherein the bending coefficients in the parallel rolling direction and the perpendicular rolling direction are both 140GPa or less, and the bending coefficient in the parallel rolling direction is (E)_RD) Deflection coefficient in the direction perpendicular to the rolling (E)_TD) Ratio E of_TD/E_RDIs 1.05 or less.

(5) A connector comprising the copper alloy sheet material according to any one of (1) to (4).

(6) A method for producing a copper alloy sheet material according to any one of (1) to (4),

sequentially carrying out melting/casting process, ingot rolling process, homogenizing heat treatment process, hot rolling process, quenching process, cold rolling 1 process, cutting/trimming process, cold rolling 2 process, intermediate melting treatment process, quenching process and aging heat treatment process,

in the ingot rolling step, rolling is performed 1 or more times at a reduction ratio such that the rolling work per pass is 1.0% or more,

in the cold rolling 1 step, the average rolling pressure per pass is 50N/mm²Rolling in a manner of above and the total working ratio of 30% or more,

in the cold rolling 2 step, the average rolling pressure per pass is 50N/mm²Rolling in a mode of the total processing rate of more than 50 percent,

in the intermediate melting treatment step, the melting treatment is performed in a high temperature region having a temperature rise rate of 5 ℃/sec or more and a reaching temperature of 600 to 1100 ℃.

(7) The method for producing a copper alloy sheet material according to item (6), wherein the aging heat treatment step is followed by an acid pickling/polishing step, a cold rolling step (3), and a final annealing step.

The above and other features and advantages of the present invention will become more apparent from the following description, with reference to the accompanying drawings where appropriate.

Effects of the invention

The copper alloy sheet material of the present invention has excellent bending workability and excellent strength, and has less anisotropy in the directions parallel to rolling and perpendicular to rolling in the bending workability and strength. Therefore, the copper alloy sheet material of the present invention is a copper alloy sheet material having properties particularly suitable for lead frames, connectors, terminal materials, and the like for electric/electronic devices, connectors, terminal materials, and the like for automobile-mounted parts, relays, switches, sockets, and the like.

Further, according to the manufacturing method of the present invention, the copper alloy sheet material can be suitably manufactured.

Drawings

Fig. 1 is an explanatory view showing the relationship between the copper alloy sheet material 1 of the present invention and the rolling direction RD, the rolling perpendicular direction (width direction) TD, and the rolling surface normal direction (thickness direction) ND. The main surface of the sheet of the copper alloy sheet material 1 is referred to as a rolled surface 2.

Fig. 2 is an explanatory view showing a surface 3 parallel to the rolling surface at a depth D smaller than the plate thickness t of the copper alloy plate material.

Detailed Description

A preferred embodiment of the copper alloy sheet material of the present invention will be described. In the present invention, the "plate material" includes a "strip material".

In the present invention, by appropriately controlling the work hardening index in the parallel rolling direction and the perpendicular rolling direction of the plate material, it is possible to increase the strength and to improve the bending workability.

Generally, strain is accumulated in a metal structure (crystal) by plastic deformation of a metal material, and work hardening occurs, whereby the material strength (proof stress, tensile strength) is increased. Here, the greater the work hardening index of the metal material, the greater the increase in strength due to work hardening of the material. On the other hand, the smaller the work hardening index of the metal material, the smaller the work hardening amount in plastic deformation such as bending and press working, and the less susceptible to the influence of the working. That is, when the amount of deformation is the same, a material having a large work hardening index is easily strengthened.

From this point of view, in bending processing for a terminal or a connector, for example, the plastic deformation amount is larger in the vicinity of the apex portion of the bending than in other positions. Therefore, when a material having a high work hardening index is subjected to bending, the work hardening amount increases, and high strength is easily achieved. In general, when the material is strengthened, the bending workability tends to be deteriorated. Therefore, when the curved surface of the terminal or the connector is locally strengthened, a crack is generated from the position where the strengthening is performed. Therefore, in order to obtain good bending workability, it is necessary to control the work hardening index to be a certain value or less. In particular, as described above, in recent connectors for electric/electronic devices, connectors for vehicle-mounted components, and the like, there are cases where a GW bend whose axis of bending is perpendicular to the rolling direction and a BW bend whose axis of bending is parallel to the rolling direction are both complicated shapes, and therefore it is desirable to appropriately control the work hardening index in both the rolling parallel direction and the rolling perpendicular direction of the plate material.

In the present invention, the texture state of the copper alloy sheet material is also controlled in addition to the control of the work hardening index. Specifically, when the thickness of the copper alloy plate material is t, the depth in the thickness direction from the surface of the rolling surface of the copper alloy plate material is D, and the area ratio of crystal grains having a deviation angle of 15 DEG or less from Cube orientation {001} < 100 > in a plane parallel to the surface of the rolling surface at the depth D of the copper alloy plate material is S (D), the average Sa of S (D) in the thickness direction is 5.0% to 30.0%, thereby improving the bending workability and reducing the anisotropy while maintaining the material strength. In this way, by controlling both the work hardening index and the texture, the flexural coefficient, which is the spring characteristic after the bending process, is also excellent.

[ alloy composition ]

First, the composition of the copper alloy constituting the plate material of the present invention will be explained.

(essential addition of elements)

The contents of the essential elements Ni and Si to be added to the copper alloy constituting the sheet material of the present invention and the operation thereof will be described.

(Ni)

Ni is contained together with Si described later to form Ni precipitated in the aging precipitation heat treatment₂Si phase, which is an element contributing to the improvement of the strength of the copper alloy sheet material. The content of Ni is 1.00 to 6.00 mass%, preferably 1.20 to 5.80 mass%, and more preferably 1.50 to 5.50 mass%. By setting the Ni content in the above range, the Ni can be appropriately formed₂Si phase capable of improving the quality of the copper alloy sheetMechanical strength (tensile strength, 0.2% proof stress) of the material. In addition, the conductivity is also high. Further, hot rolling workability was also good.

(Si)

Si is contained together with the Ni to form Ni precipitated in the aging precipitation heat treatment₂The Si phase contributes to the improvement of the strength of the copper alloy sheet. The content of Si is 0.20 to 2.00 mass%, preferably 0.25 to 1.90 mass%, and more preferably 0.50 to 1.70 mass%. The best balance between conductivity and strength is 4.2 in terms of stoichiometric ratio for the Si content. Therefore, the content of Si is preferably in the range of 2.50 to 7.00, more preferably 3.00 to 6.50, in terms of Ni/Si. By setting the Si content in the above range, the tensile strength of the copper alloy sheet material can be improved. In this case, excessive Si is dissolved in the copper matrix, and the electrical conductivity of the copper alloy sheet is not lowered. Further, the castability during casting and the rolling workability in hot and cold conditions were also good, and no casting cracks or rolling cracks were generated.

(additional element)

Next, the kind of the sub-additive elements in the copper alloy constituting the plate material of the present invention and the effect of the addition thereof will be described. Preferable examples of the additive elements include B, Mg, P, Cr, Mn, Fe, Co, Zn, Zr, Ag and Sn. When the total amount of these elements is 3.000 mass% or less, adverse effects of lowering the conductivity are not caused, and therefore, it is preferable. In order to sufficiently utilize the effect of addition without lowering the conductivity, the total amount is preferably 0.005 to 3.000 mass%, more preferably 0.010 to 2.800 mass%, and particularly preferably 0.030 to 2.500 mass%. The effect of addition of each element is shown below.

(Mg、Sn、Zn)

The stress relaxation resistance is improved by adding Mg, Sn, Zn. In the case of adding the components in combination, the stress relaxation resistance is further improved by utilizing the synergistic effect as compared with the case of adding the components separately. Further, there is an effect that embrittlement of the solder is significantly improved. The content of each of Mg, Sn, and Zn is preferably 0.00 to 2.00 mass%, and more preferably 0.10 to 1.80 mass%.

(Mn、Ag、B、P)

When Mn, Ag, B and P are added, hot workability is improved and strength is improved. The content of each of Mn, Ag, B, and P is preferably 0.00 mass% to 1.00 mass%, and more preferably 0.050 mass% to 0.70 mass%.

(Cr、Zr、Fe、Co)

Cr, Zr, Fe, and Co are finely precipitated as compounds and simple substances, and contribute to precipitation hardening. Further, the compound precipitates in a size of 50nm to 500nm, and has an effect of making the crystal grain size fine by suppressing grain growth, thereby improving the bending workability. The respective contents of Cr, Zr, Fe, and Co are preferably 0.00 to 1.50 mass%, and more preferably 0.10 to 1.30 mass%.

[ work hardening index ]

In the copper alloy sheet material of the present invention, the work hardening index n in the rolling parallel direction of the sheet material_RDIs 0.01 to 0.15, preferably 0.01 to 0.10, more preferably 0.01 to 0.08, and still more preferably 0.01 to 0.06.

In addition, work hardening index n in the direction perpendicular to rolling of the plate_TDPreferably 0.01 to 0.15, more preferably 0.01 to 0.10, still more preferably 0.01 to 0.08, and particularly preferably 0.01 to 0.06.

Further, work hardening index n in the direction parallel to rolling_RDWork hardening index n in the direction perpendicular to rolling_TDRatio n of_RD/n_TDIs 0.50 to 1.50, preferably 0.70 to 1.40, more preferably 0.75 to 1.35, and still more preferably 0.80 to 1.30. By controlling the work hardening index to be the above, the Cube orientation area ratio can be easily controlled.

The reason why the work hardening index is set to be in this range is because, by setting the work hardening index to be constant or less, the work hardening amount at the time of bending the terminal is small, and good workability tends to be obtained.

[ texture ]

In the copper alloy sheet material of the present invention, when the sheet thickness of the copper alloy sheet material is represented by t, the depth of the copper alloy sheet material in the sheet thickness direction from the surface of the rolled surface is represented by D, and the area ratio of crystal grains having a deviation angle of 15 DEG or less from Cube orientation {001} < 100 > in a plane parallel to the surface of the rolled surface at the depth D of the copper alloy sheet material is represented by S (D), the average Sa of S (D) in the sheet thickness direction is 5.0% or more and 30.0% or less. For Cube orientation analysis, crystal orientation analysis in EBSD measurement was used. The area ratio of crystal grains having a deviation angle of 15 ° or less (including 0 °) from Cube orientation {001} < 100 > is the area ratio of Cube orientation. This is a ratio of an area of a crystal grain region having a deviation angle from Cube orientation of 15 ° or less in a total area of a surface when the surface is viewed from the plate thickness direction.

Fig. 1 is a diagram showing the relationship between the copper alloy sheet material 1 of the present invention and the rolling direction RD, the rolling perpendicular direction (width direction) TD, and the rolling surface normal direction (thickness direction) ND. The main surface of the sheet of the copper alloy sheet material is referred to as a rolled surface 2. Fig. 2 shows a plane 3 parallel to the rolling surface at the depth D of the copper alloy sheet.

The copper alloy sheet is generally produced by repeating rolling, and has a texture related to a rolling direction or the like. This texture is expressed with RD, TD, and ND perpendicular to each other as reference axes. The grain with Cube orientation {001} < 100 > referred to in the present invention means a state in which the {001} plane of the crystal is perpendicular to ND and the < 100 > direction of the crystal is parallel to RD with respect to the crystal (face-centered cubic lattice) of copper in the grain.

In the copper alloy sheet material of the present invention, the average Sa of the area ratios S (D) in the thickness direction of the surface 3 parallel to the rolled surface at the depth D from the surface is 5.0% to 30.0% with respect to the area ratio S (D) of the crystal grains having Cube orientation. That is, with respect to the surface 3 parallel to the rolled surface at the depth D in fig. 2, the area ratio of Cube orientation of the surface is s (D), and the average value of s (D) is Sa. The depth D takes a value of 0 to t. Therefore, the concept of Sa is expressed as a mathematical expression as follows.

[ number 1]

However, it is physically difficult to calculate Sa by measuring the area ratio s (D) of Cube orientations in all the surfaces from the front surface (D ═ 0) to the back surface (D ═ t) of the copper alloy sheet material. Therefore, in the present invention, Sa is obtained by measuring S (D1), S (D2) and. cndot. cndot.5 or more depths D1, D2 and. cndot. cndot.. The depth D is particularly preferably 5 kinds of D — 1/20t, 1/4t, 1/2t, 3/4t, and 19/20 t. In the thickness direction, it is preferable to select two or more depths D with respect to the center of the thickness (D: 1/2 t).

Hereinafter, the average Sa of the area ratios is also referred to as "the average of the area ratios of Cube orientations in the plate thickness direction". The average value of the area ratios of Cube orientations in the plate thickness direction is preferably 8.0% to 30.0%. By controlling Sa to 5.0% or more, the bending workability can be improved. This is considered to be because the occurrence of shear bands due to bending can be suppressed. Similarly, the occurrence of shear bands associated with compression deformation can be suppressed by setting the Cube orientation area ratio to 5.0% or more on the back surface in the plate thickness direction during bending. Further, by controlling the Cube orientation area ratio in the vicinity of the center of the sheet thickness to 5.0% or more, the development of cracks accompanying deformation can be suppressed in the same manner as the front surface and the back surface. Therefore, each value of the area ratio s (D) of the crystal grains having Cube orientation in the plane 3 parallel to the rolled surface at the depth D is also preferably 5.0% or more and 30.0% or less.

(evaluation of texture distribution in the thickness direction)

The area ratio of Cube-oriented grains in the copper alloy was measured by changing the amount of polishing in order to examine the distribution in the thickness direction. To observe the tissue from the plate thickness direction, one surface of the test piece was masked, and only the opposite surface was electropolished. At this time, polishing was performed while paying attention to the mirror finish of the test piece surface. In fact, it is understood that the microstructure can be grasped by fine adjustment of the polishing amount by electrolytic polishing, and detailed analysis can be performed by EBSD analysis. In the measurement of the prepared test piece, the area ratio of Cube-oriented crystal grains was measured by scanning in a range of 300. mu. m.times.300. mu.m at 0.1 μm steps by EBSD orientation analysis.

(EBSD method)

In the present invention, the EBSD method is used for the analysis of the crystal orientation. The EBSD method is an abbreviation of electron back scatter Diffraction, and is a crystal orientation analysis technique using electron Diffraction reflected from chrysanthemums generated when a sample is irradiated with an electron beam in a Scanning Electron Microscope (SEM). The crystal orientation of each crystal grain was analyzed by scanning a sample area of 300. mu. m.times.300 μm containing 200 or more crystal grains at a pitch of 0.1 μm. The measurement area and the scanning pitch were set to 300X 300. mu.m and 0.1. mu.m depending on the size of the sample crystal grains. The area ratio of each orientation can be determined by obtaining the area of a crystal grain having a normal line to the crystal grain in a range within ± 15 ° from an ideal orientation of Cube orientation {001} < 100 > and determining the area ratio of each orientation as a ratio of the obtained area to the total measured area. The information obtained in the orientation analysis by EBSD includes orientation information of a depth of up to several 10nm where an electron beam enters a sample, but is sufficiently small relative to the measurement width, and therefore is described as an area ratio in the present specification. In addition, OIM Analysis (product name) was used for Analysis of EBSD measurement results.

[ method for producing copper alloy sheet Material ]

First, a conventional method for producing a precipitation-type copper alloy will be described.

In a conventional method for producing a precipitation type copper alloy, a copper alloy material is melted/cast [ step 1] to obtain an ingot, which is subjected to a homogenization heat treatment [ step 3], hot rolling [ step 4], water cooling [ step 5], surface cutting [ step 6] and cold rolling [ step 7] in this order to be thinned, and the intermediate melting treatment [ step 10], the aging precipitation heat treatment [ step 11] and the finish cold rolling [ step 13] are performed at a temperature of 700 to 1000 ℃ to satisfy a required strength. After finish cold rolling [ step 13], final annealing for strain relief [ step 14] may be performed. Further, an oxide film removing step (pickling/polishing step 12) may be added between the aging precipitation heat treatment step (step 11) and the finish cold rolling step (step 13). In this series of steps, the texture of the material is roughly determined by recrystallization occurring in the intermediate melt processing, and is finally determined by the rotation of orientation occurring in the finish cold rolling.

In contrast, in the method of the present invention, a copper alloy sheet material is produced through a production process different from the conventional method, wherein the average Sa of Cube orientation area ratios in the sheet thickness direction, and the work hardening indexes in both the rolling parallel direction and the rolling perpendicular direction are controlled.

Specifically, in the present invention, melting/casting [ step 1], ingot rolling [ step 2], homogenization heat treatment [ step 3], hot rolling [ step 4], water cooling [ step 5], surface cutting [ step 6], cold rolling 1[ step 7], cutting/dressing [ step 8], cold rolling 2[ step 9], intermediate melting treatment [ step 10], water cooling [ step 10-2], aging precipitation heat treatment [ step 11], acid washing/polishing [ step 12], cold rolling 3[ step 13], and final annealing [ step 14] are performed in this order. The pickling/polishing [ step 12], the cold rolling 3[ step 13] and the final annealing [ step 14] may be omitted as long as the sheet material having desired properties can be obtained.

Wherein a predetermined additive element is added to the melt/casting [ step 1] to obtain an ingot. The cooling rate during casting is usually 0.1 ℃/sec to 100 ℃/sec.

Then, in the ingot rolling [ step 2], a certain cold rolling is applied to the ingot to partially recrystallize near the grain boundaries during the homogenization heat treatment, and further, to contribute to the formation of equiaxed grains in the subsequent recrystallization of the intermediate melt. The rolling reduction ratio per pass in the ingot rolling [ step 2] is 1.0% or more (preferably 5.0% or less), and the number of passes is 1 or more.

Then, homogenization heat treatment is performed so that the temperature is 800 ℃ to 1100 ℃ inclusive and the holding time is5 minutes to 20 hours [ step 3 ]. Thereafter, hot rolling is performed in a working temperature region of 1100 ℃ or lower (preferably 800 ℃ or higher) in a plurality of passes [ step 4] until a predetermined plate thickness is reached, and cooling (quenching, so-called quenching) is performed immediately after the completion of the hot rolling by water cooling [ step 5 ]. Thereafter, surface cutting is performed to remove the oxide film on the surface of the hot rolled material [ step 6], and then cold rolling 1 is performed [ step 7 ].

In cold rolling 1[ step 7]]In the above-described cold rolling, the cold rolling is performed in several to several tens passes so that the total rolling reduction rate becomes 30% or more (preferably 60% or less). In order to grow a certain Cube-oriented grain at the time of recrystallization and control the work hardening index, the average rolling pressure at the time of rolling per pass was controlled to 50N/mm²The above.

Next, in order to adjust the shape of the material end during cold rolling, cutting is performed [ step 8], and both unnecessary ends are removed by trimming.

Thereafter, cold rolling 2[ step 9]]The cold rolling is performed in several to several tens passes so that the total rolling reduction rate is 50% or more (preferably 80% or less). Here, the average rolling pressure per pass of rolling is controlled to 50N/mm in order to grow Cube-oriented grains during recrystallization and to control the work hardening index²The above.

Thereafter, the solute element is dissolved at a temperature rise rate of 5.0 ℃/sec or more and an arrival temperature of 600 to 1100 ℃ by an intermediate melting treatment [ step 10], and the solution is held at the arrival temperature for a certain period of time (preferably 1 second to 5 hours), whereby Cube-oriented crystal grains are formed as the grains grow. Although the worked structure is temporarily formed in the cold rolling 1 and the cold rolling 2 before the intermediate melting treatment [ step 10], the equiaxed grains described below can be obtained by recrystallization by the intermediate melting treatment [ step 10 ]. When the temperature and time are satisfied, water cooling is performed to rapidly perform cooling (so-called quenching) (step 10-2).

Then, an aging precipitation heat treatment is performed at a holding temperature of 400 to 700 ℃ for 5min to 10 hours to satisfy the required strength [ step 11 ].

Thereafter, in order to remove the oxide film on the surface of the plate material, pickling/polishing is performed as necessary [ step 12 ]. Thereafter, final finish rolling is performed by cold rolling 3[ step 13] as necessary. In the case of cold rolling 3[ step 13] performed to maintain the equiaxed grains formed in the intermediate melting treatment [ step 10], the rolling reduction is performed at a rolling reduction ratio of 1.0% or more and as low as possible. The upper limit of the reduction ratio in the cold rolling 3[ step 13] is preferably 40% or less.

Then, the strain in the sheet material is removed by final annealing (thermal annealing) at 200 to 700 ℃ for 1 minute to 5 hours, if necessary [ step 14 ]. This final anneal is also referred to as a de-strain anneal.

Preferred conditions for each step will be described in more detail below.

In the ingot rolling [ step 2], cold rolling is applied to the ingot, whereby nuclei are generated in the vicinity of grain boundaries at the time of reheating in the homogenization heat treatment of the next step, and further, the nuclei contribute to the formation of equiaxed grains in the recrystallization in the subsequent intermediate melting. The cold rolling reduction rate per pass is 1.0% or more, and the number of passes is 1 or more. The cold rolling reduction per pass is preferably 2.0% or more and the number of passes is 3 or more, and more preferably the cold rolling reduction per pass is 3.0% or more and the number of passes is5 or more.

In cold rolling 1[ step 7]]In order to control the subsequent intermediate melting treatment [ step 10]]The Cube orientation area ratio and work hardening index at the time of medium recrystallization are rolled several times to several tens of times so that the total work ratio is 30% or more, and the average rolling pressure per pass is controlled to 50N/mm²The above. Preferably, the average rolling pressure is 60N/mm²Above, more preferably 70N/mm²The above.

In the cold rolling 2[ step 9]]And cold rolling 1[ step 7]]Similarly, the intermediate melting treatment is controlled [ step 10]]The Cube orientation area ratio and work hardening index at the time of medium recrystallization are rolled several times to several tens of times so that the total working ratio is 50%, and the average rolling pressure per pass is controlled to 50N/mm²The above. Preferably, the average rolling pressure is 60N/mm²Above, more preferably 70N/mm²The above.

In the subsequent intermediate melting treatment [ step 10], by recrystallization in a high temperature region at a temperature rise rate of 5 ℃/sec or more and a temperature of 600 to 1100 ℃, equiaxed grains are obtained in which the ratio a/b of the average grain diameter (dimension) a in the parallel direction to the rolling and the average grain diameter b in the perpendicular direction to the rolling is 0.8 or more. Since the number of equiaxed grains is large, anisotropy of work hardening index is reduced. The grain size ratio a/b is preferably 0.85 or more, more preferably 0.9 or more (preferably 1.1 or less). Since the reduction ratio of the cold rolling 3 after the intermediate melting treatment is small, the crystal grain size a/b of the base material of the copper alloy sheet material of the present invention is 0.8 or more even if the rolling is performed under the condition of the cold rolling 3[ step 13 ].

Here, the reduction ratio (or the reduction ratio of the cross section during rolling) is a value defined by the following equation.

Machining rate (%) { (t1-t2)/t1} × 100

In the formula, t1 represents the thickness before rolling, and t2 represents the thickness after rolling.

[ thickness of plate ]

The thickness of the copper alloy sheet material of the present invention is not particularly limited, but is preferably 0.04mm to 0.50mm, and more preferably 0.05mm to 0.45 mm.

[ characteristics of copper alloy sheet Material ]

The copper alloy sheet material of the present invention can satisfy the characteristics required for a copper alloy sheet material for connectors, for example. The copper alloy sheet material of the present invention preferably has the following characteristics.

In terms of bending workability, it is preferable that cracks not occur on the surface after bending in any of the cases where the axis of bending is perpendicular to the rolling direction (GW bending) and parallel to the rolling direction (BW bending) in a 180 ° U bending test in which R/t represented by a bending radius R and a plate thickness t is 1.0. Further, it is preferable that the test piece having a narrow width of 1.0mm or less is similarly subjected to 180 ° U bending with an R/t of 1.0, and has bending workability such that no crack is generated on the surface after either of the GW bending and the BW bending.

The Tensile Strength (TS) of the sheet is preferably 650MPa or more in both the rolling parallel direction (RD) tensile strength (TS-RD) and the rolling perpendicular direction (TD) tensile strength (TS-TD) of the sheet. Further, the ratio TS-RD/TS-TD is preferably 1.10 or less, more preferably 1.08 or less. The upper limit of the tensile strength is not particularly limited, and is, for example, 1020MPa or less.

The 0.2% proof stress (YS) of the sheet material is preferably 600MPa or more of the 0.2% proof stress (YS-RD) in the direction parallel to the rolling direction and the 0.2% proof stress (YS-TD) in the direction perpendicular to the rolling direction of the sheet material. The ratio YS-RD/YS-TD is preferably 1.10 or less, and more preferably 1.08 or less. The upper limit of the 0.2% proof stress is not particularly limited, and is, for example, 1000MPa or less.

The bending modulus (E) after the 180 DEG bending is preferably 140GPa or less in both the bending modulus (E-RD) in the direction parallel to the rolling direction and the bending modulus (E-TD) in the direction perpendicular to the rolling direction of the plate material. Further, the ratio E-RD/E-TD is preferably 1.05 or less, more preferably 1.03 or less. The upper limit of the flexural coefficient is not particularly limited, and is, for example, 140GPa or less.

The conductivity is preferably 20.0% or more of ICAS. Here, "% IACS" represents the conductivity when the resistivity of the International Standard soft Copper (International interconnected coater Standard) is 1.7241 × 10-8 Ω m, which is 100% IACS. The upper limit of the conductivity is not particularly limited, and is, for example, 50% IACS or less.

The detailed measurement conditions for each characteristic are as described in the examples unless otherwise specified.

Examples

The present invention will be described in further detail below with reference to examples, but the present invention is not limited to these examples.

(examples 1 to 16 and comparative examples 1 to 14)

In each of examples and comparative examples, an alloy material containing Ni and Si in respective amounts shown in table 1 and, if necessary, additional elements and the like, and the balance being Cu and inevitable impurities was melted in a high-frequency melting furnace, and the alloy material was cooled at a cooling rate of 0.1 ℃/sec to 100 ℃/sec and cast [ step 1], thereby obtaining an ingot.

The ingot is processed at a processing rate of 1.0% or more and a pass number of 1 or moreIngot rolling by cold rolling [ step 2]]. Then, the ingot is subjected to a homogenization heat treatment at 800 to 1100 ℃ for 5 minutes to 20 hours [ step 3]]. Then, hot rolling is performed at 800 ℃ to 1100 ℃ as hot working [ step 4]]Further, water quenching and cooling are performed [ step 5]]And obtaining the hot rolled plate. Next, the surface of the hot-rolled sheet is subjected to surface cutting [ step 6]]The oxide film is removed. Thereafter, cold rolling 1[ step 7]]Rolling is performed in several to several tens of passes to achieve a total reduction ratio of 30% or more. The average rolling pressure per pass at this time was 50N/mm²The above. Then, both ends of the rolled material are cut [ step 8]]. Thereafter, cold rolling 2[ step 9]]Rolling in several to several tens passes to obtain a total working ratio of 50% or more and an average rolling pressure of 50N/mm per pass²The above. Thereafter, an intermediate melting treatment is performed [ step 10]]Heat treatment is carried out at a temperature rise rate of 5 ℃/sec or more and at a reaching temperature of 600 to 1100 ℃ for 1 second to 5 hours, and then quenching is carried out [ step 10-2]]. Here, by recrystallization in a high temperature region, equiaxed grains are obtained in which the ratio a/b of the dimension a in the parallel direction to the rolling direction to the dimension b in the perpendicular direction to the rolling direction is 0.8 or more. Then, an aging precipitation heat treatment is performed at a holding temperature of 400 to 700 ℃ for a holding time of 5min to 10 hours [ step 11]]So that it meets the required strength. Then, in order to remove the oxide film on the surface of the plate material, pickling/polishing is performed [ step 12]]. Thereafter, cold rolling is performed 3[ step 13]]And carrying out final finish rolling. In the cold rolling 3[ step 13]]In order to maintain the intermediate melting treatment [ step 10]]The equiaxed grains formed in (1) above are rolled at a rolling reduction rate as low as possible of 1.0%. Specifically, cold rolling is performed 3[ step 13]]The rolling processing rate is 1.0-40.0%. Then, final annealing is performed by holding the steel sheet at 200 to 700 ℃ for 1 minute to 5 hours [ step 14]]And removing the strain in the plate.

As shown in table 2, the production conditions of the examples and comparative examples are changed from the above conditions to the column of "step X" (X is the number of steps).

As described above, a copper alloy sheet having a final sheet thickness (t) of 0.15mm was obtained.

The following characteristic study was performed for each sample.

(a) Work hardening index [ n value ]

For the test pieces of the examples and comparative examples, the work hardening index was measured from the slope of the plastic deformation region of the stress-strain curve by a tensile test using a test piece No. JIS 5. The tensile test was performed according to JIS Z2241. For the evaluation criteria, the work hardening index (n) in the direction parallel to the rolling direction was set_RD) A work hardening index (n) in the direction perpendicular to rolling is set to 0.010 to 0.150 as a pass_TD) A work hardening index (n) in a direction parallel to the rolling direction of 0.010 to 0.150_RD) Work hardening index (n) in the direction perpendicular to rolling_TD) Ratio n of_RD/n_TDThe value is 0.500 to 1.500, and the value outside the range is determined as pass, and the value is determined as fail.

(b) Cube orientation area ratio

The samples of examples and comparative examples were subjected to EBSD measurement of crystal orientation under conditions of a measurement area of 300. mu. m.times.300. mu.m and a scanning pitch of 0.1. mu.m. In the analysis, the EBSD measurement result of 300. mu. m.times.300. mu.m was divided into 25 blocks, and the area ratio of the crystal grains having Cube orientation in each block was confirmed as follows. The electron beam uses thermal electrons from a W filament of a scanning electron microscope as a generation source. OIM5.0 (product name) manufactured by TSL Solutions was used as a measuring device for the EBSD method, and OIM Analysis was used for Analysis.

Further, in polishing before EBSD measurement, the target portion tissue is exposed by electropolishing for tissue observation. The exposed portions after the polishing were observed at 5 positions with EBSD where the depth D was 1/20t, 1/4t, 1/2t, 3/4t, and 19/20t with respect to the plate thickness t. The occupancy rate (i.e., area ratio) of Cube-oriented crystal grains with respect to the measurement field of view was obtained for each of the 5 positions. Then, the average Sa of the area ratios of the 5 positions was obtained and is shown as "average (%) in the sheet thickness direction of Cube orientation area ratio".

(c)180 degree U bend test

For the test materials of the examples and comparative examples, a test piece in a rolling perpendicular direction and a test piece in a rolling parallel direction, which were punched out by pressing so as to be perpendicular to the rolling direction and to have a width of 0.25mm and a length of 1.5mm, were subjected to the test; the test piece in the parallel rolling direction was punched out by pressing so as to be parallel to the rolling direction and to have a width of 0.25mm and a length of 1.5 mm. The case of W bending a test piece in the parallel rolling direction with a bent axis at right angles to the rolling direction was referred to as gw (good way), and the case of W bending a test piece in the perpendicular rolling direction with a bent axis parallel to the rolling direction was referred to as bw (bad way), and after 90 ° W bending processing was performed according to the japanese copper drawing association technical standard JCBA-T307(2007), 180 ° tight bending processing was performed by a compression tester without applying an inside radius. The curved surface was observed with a 100-fold scanning electron microscope to examine the presence or absence of cracks. The case without cracks is set as "good" and is represented by "a"; the case of cracking was regarded as "poor" and indicated by "D". When cracks are generated, the maximum width is 30 to 100 μm and the maximum depth is 10 μm or more with respect to the size of the cracks.

(d) Tensile Strength [ TS ]

For the test materials of the examples and comparative examples, a rolling perpendicular direction test piece punched out by pressing so as to be perpendicular to the rolling direction, have a width of 0.25mm and a length of 1.5mm was subjected to a tensile test, and a rolling perpendicular direction tensile strength (TS-TD) was obtained. Further, a test piece in the parallel rolling direction, which was punched out by pressing so as to be parallel to the rolling direction and to have a width of 0.25mm and a length of 1.5mm, was subjected to a tensile test to obtain a tensile strength (TS-RD) in the parallel rolling direction. The tensile strength was measured according to JIS Z2241.

Anisotropy in the direction parallel to rolling and in the direction perpendicular to rolling of the tensile strength was confirmed. The TS of 600MPa or more is defined as pass, and the TS of less than 600MPa is defined as fail.

(e) Conductivity [ EC ]

The electric conductivity was calculated by measuring the resistance in a constant temperature bath maintained at 20 ℃ (± 0.5 ℃) by a four-terminal method. The distance between the terminals was 100 mm. The EC was determined to be not less than 20% IACS, and the TS was determined to be less than 20% IACS.

(f) Flexural modulus [ E ]

The rolling perpendicular deflection coefficient (E) was determined from the rolling perpendicular test piece of each of the test materials of examples and comparative examples based on JCBA T312 which is a technical standard of the Japan copper elongation Association_TD) The test piece in the vertical direction of rolling was punched out by pressing so as to have a width of 0.25mm and a length of 1.5mm, which were perpendicular to the direction of rolling. Further, from the test piece in the parallel rolling direction, the bending coefficient (E) in the parallel rolling direction was determined_RD) The test piece in the parallel rolling direction was punched out by pressing so as to be parallel to the parallel rolling direction and to have a width of 0.25mm and a length of 1.5 mm. The samples were taken from 5 positions in the width direction of the coil, and the average of the measurement results was taken.

The test pieces bent at 180 ° U were fixed to a jig, and the test pieces were each pressed 10 times to obtain the average values of the displacement (pressing depth) f and the stress w.

The flexural modulus E (GPa) is represented by the following formula (1).

E＝4a/b×(L/t)3(1)

a is the slope of the displacement (depth of penetration) f and the stress w, b is the width of the test piece, L is the distance between the fixed end and the load point, and t is the thickness of the test piece. The fixed end in L is the apex of the curve.

Anisotropy of the flexural modulus in the rolling parallel direction and the rolling perpendicular direction was confirmed. E is 110GPa or more and E is less than 110 GPa.

(g) 0.2% proof stress [ YS ]

For the samples of each example and comparative example, the proof stress in the rolling perpendicular direction (YS-TD) was determined from a test piece in the rolling perpendicular direction which was punched out by pressing so as to be perpendicular to the rolling direction and to have a width of 0.25mm and a length of 1.5 mm. The rolling parallel direction 0.2% proof stress (YS-RD) was obtained from a rolling parallel direction test piece punched out by pressing so as to be parallel to the rolling direction and have a width of 0.25mm and a length of 1.5 mm.

In the measurement of the flexural coefficient, the 0.2% proof stress y (mpa) was calculated from the indentation amount (displacement) to the elastic limit of each test piece by the following formula (2).

Y＝{(3E/2)×t×(f/L)×1000}/L(2)

E is a deflection coefficient, t is a plate thickness, L is a distance between a fixed end and a load point, and f is a displacement.

Anisotropy in the rolling parallel direction and the rolling perpendicular direction of 0.2% proof stress was confirmed. YS of 600MPa or more is regarded as pass, and YS of less than 600MPa is regarded as fail.

[ TABLE 1]

TABLE 1

	Ni	Si	B	Mg	P	Cr	Mn	Fe	Co	Zn	Zr	Ag	Sn
														Example 1	3.750	0.950	-	0.150	-	0.200	-	-	-	0.500	-	-	0.150
Example 2	2.300	0.600	-	0.150	-	0.150	-	-	-	0.500	-	-	0.150
														Example 3	3.800	0.900	-	0.150	-	0.190	-	-	-	0.450	-	-	0.140
Example 4	3.800	0.900	-	0.100	-	0.150	-	-	-	0.400	-	-	0.150
														Example 5	2.300	0.550	-	0.100	-	-	-	-	-	0.500	-	-	0.150
Example 6	3.850	0.650	-	0.100	-	0.100	-	-	-	0.400	-	-	0.100
														Example 7	2.500	0.600	-	0.050	-	-	-	-	-	0.050	-	-	-
Example 8	3.000	0.650	-	0.150	-	-	-	-	-	-	-	-	-
														Example 9	1.500	0.600	-	-	-	-	-	-	1.150	-	-	-	-
Example 10	2.490	0.910	-	-	-	-	-	-	1.310	-	-	-	-
														Example 11	2.800	0.600	-	-	-	-	-	-	-	0.400	-	-	0.500
Example 12	4.800	1.100	0.010	0.100	-	0.300	-	-	-	-	0.050	-	0.100
														Example 13	5.300	1.300	-	-	-	0.100	-	-	-	0.100	-	-	0.100
Example 14	6.000	1.800	-	-	-	0.200	-	-	-	0.100	-	-	0.200
														Example 15	3.000	0.850	-	0.100	0.200	0.500	0.120	0.100	-	1.350	0.100	0.300	0.200
Example 16	2.300	0.500	-	-	-	-	-	-	0.005	-	-	-	-
														Comparative example 1	1.500	0.600	-	-	-	-	-	-	1.150	-	-	-	-
Comparative example 2	2.000	0.500	-	-	-	-	-	-	-	1.000	-	-	0.500
														Comparative example 3	2.800	0.650	-	-	-	-	-	-	-	0.600	-	-	0.500
Comparative example 4	3.200	0.700	-	-	-	-	-	-	-	0.400	-	-	0.500
														Comparative example 5	2.800	0.600	-	-	-	-	-	-	-	0.400	-	-	0.500
Comparative example 6	3.800	0.800	-	0.200	-	-	0.150	-	-	-	-	-	-
														Comparative example 7	2.700	0.600	0.050	-	-	-	-	-	-	1.500	-	0.050	0.300
Comparative example 8	3.000	0.700	-	0.300	0.100	0.400	-	-	-	1.000	0.900	0.050	0.300
														Comparative example 9	6.400	2.200	-	0.100	-	0.200	-	-	-	0.400	-	-	0.500
Comparative example 10	0.900	0.070	-	-	-	-	-	-	-	-	-	-	-
														Comparative example 11	0.850	0.200	-	-	-	0.100	-	0.010	-	0.400	-	-	0.300
Comparative example 12	6.500	1.750	-	0.100	-	-	-	-	-	-	-	-	-
														Comparative example 13	1.200	0.150	-	0.100	-	-	0.120	-	-	0.200	-	-	-
Comparative example 14	5.900	2.350	-	0.100	-	0.100	-	-	-	-	0.100	-	-

Note: the unit is% by mass and "-" is not included.

[ TABLE 2]

From the results shown in table 2, it is understood that the bending workability, tensile strength, 0.2% proof stress, electrical conductivity, and flexural coefficient are all good in the samples according to the examples of the present invention. In the bending workability, no crack was generated at the bent top in the 180 ° U bend test. In particular, the bending workability, tensile strength, 0.2% proof stress, electrical conductivity, and flexural modulus are small in anisotropy in both the rolling parallel direction and the rolling perpendicular direction.

Therefore, the copper alloy sheet material of the present invention is preferably used as a copper alloy sheet material suitable for lead frames, connectors, terminal materials, and the like for electric/electronic devices, connectors, terminal materials, relays, switches, sockets, and the like for automobiles and the like.

On the other hand, as is clear from the results shown in table 2, the samples of the comparative examples were inferior in any of the characteristics.

Comparative examples 1 to 7 are test examples manufactured under manufacturing conditions not specified in the present invention. In comparative examples 1 to 7, both the work hardening index and the average Sa of Cube orientation area ratio were outside the range specified in the present invention. The bending workability was poor in comparative examples 2 to 7, and the anisotropy in the rolling parallel direction and the rolling perpendicular direction was large and poor in all of comparative examples 1 to 7, in which any of the tensile strength, 0.2% proof stress, electric conductivity, and flexural coefficient was large.

Further, comparative examples 8 to 14 are test examples of alloy compositions deviating from the composition defined in the present invention. The average Sa of Cube orientation area ratios of comparative examples 8 to 14 is outside the range specified in the present invention. In comparative examples 8 to 14, at least 1 or more of them were inferior in bending workability, tensile strength, 0.2% proof stress, electrical conductivity, and flexural coefficient, including anisotropy in the rolling parallel direction and the rolling perpendicular direction.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

The present application claims priority based on japanese special application 2014-112974 filed in japan patent application 5, 30, 2014, the contents of which are incorporated by reference as part of the description of the present specification.

Description of the symbols

1 copper alloy sheet

2 rolled noodles

3 a surface parallel to the surface of the rolled surface at a depth D smaller than the thickness t of the copper alloy plate material (1)

Claims

1. A copper alloy sheet material having a composition of: 1.0 to 6.0 mass% of Ni, 0.2 to 2.0 mass% of Si, Ni/Si being 3.95 to 5.92, and containing 0.000 to 3.000 mass% in total of at least 1 selected from the group consisting of 0 to 0.01 mass% of B, 0 to 0.15 mass% of Mg, 0 to 0.20 mass% of P, 0 to 0.50 mass% of Cr, 0 to 0.12 mass% of Mn, 0 to 0.10 mass% of Fe, 0 to 1.31 mass% of Co, 0 to 1.35 mass% of Zn, 0 to 0.10 mass% of Zr, 0 to 0.30 mass% of Ag and 0 to 0.50 mass% of Sn, the balance being composed of copper and unavoidable impurities, wherein any one of the above B, Mg, P, Cr, Mn, Fe, Co, Zn, Zr, Sn and Ag may or more be contained, but is an optional additive component, the copper alloy sheet is characterized in that,

work hardening index n in the direction parallel to the rolling_RDIs 0.010 to 0.150,

work hardening index n in the direction parallel to the rolling_RDWork hardening index n in the direction perpendicular to rolling_TDRatio n of_RD/n_TDIs in the range of 0.500 to 1.500,

2. The copper alloy sheet according to claim 1, wherein the total amount of 0.005 to 3.000 mass% of at least 1 selected from the group consisting of 0 to 0.01 mass% of B, 0 to 0.15 mass% of Mg, 0 to 0.20 mass% of P, 0 to 0.50 mass% of Cr, 0 to 0.12 mass% of Mn, 0 to 0.10 mass% of Fe, 0 to 1.31 mass% of Co, 0 to 1.35 mass% of Zn, 0 to 0.10 mass% of Zr, 0 to 0.30 mass% of Ag, and 0 to 0.50 mass% of Sn is contained.

3. The copper alloy sheet according to claim 1 or 2, wherein the bending coefficients in both the parallel rolling direction and the perpendicular rolling direction are 140GPa or less, and the ratio E-RD/E-TD of the bending coefficient E-RD in the parallel rolling direction to the bending coefficient E-TD in the perpendicular rolling direction is 1.05 or less.

4. A connector comprising the copper alloy sheet material according to any one of claims 1 to 3.

5. A method for producing a copper alloy sheet according to any one of claims 1 to 3, wherein the copper alloy sheet is produced by a method comprising the steps of,

6. The method of manufacturing a copper alloy sheet according to claim 5, wherein the aging heat treatment step is followed by a pickling/polishing step, a cold rolling step 3, and a final annealing step in this order.