KR101935987B1 - Copper alloy sheet, connector comprising copper alloy sheet, and method for producing copper alloy sheet - Google Patents

Abstract

At least one kind selected from the group consisting of B, Mg, P, Cr, Mn, Fe, Co, Zn, Zr, Ag and Sn is contained in an amount of 1.0 to 6.0% by mass and 0.2 to 2.0% And a balance of copper and inevitable impurities, wherein the work hardening index n _RD in the rolling parallel direction (RD) is 0.010 to 0.150, and the n _{RD is a} direction perpendicular to the rolling direction TD) work-hardening exponent n _TD ratio n _RD / n it is the _TD is 0.500 ~ 1.500, according to a plane parallel with the rolling plane surface in which the copper alloy plate depth D, Cube orientation {001} <100> of the And the average value Sa of the area ratio S (D) of the crystal grains having a stagger angle within 15 degrees from 5.0 to 30.0% is superior in bending workability, has excellent strength, and has a spring characteristic after bending And the bending workability, the strength and the bending coefficient angle The specificity of the castle from the rolling direction and the direction perpendicular to rolling provides a small copper alloy material.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a copper alloy sheet material, a connector made of a copper alloy sheet material, and a method of manufacturing a copper alloy sheet material,

The present invention relates to a copper alloy sheet material and a manufacturing method thereof. Particularly, it is excellent in bending workability and strength and spring characteristics after bending, and can be applied to lead frames, connectors, terminal materials, relays, switches, sockets and the like for automotive parts and electric / Copper alloy sheet material and a method of manufacturing the same.

The characteristics required for a copper alloy sheet used for a lead frame, a lead frame, a connector, a terminal, a relay, a switch, and a socket for a vehicle component or an electric or electronic device include a conductivity, a proof stress (yield stress) And bending workability. 2. Description of the Related Art In recent years, along with the miniaturization, light weight, high performance, high density mounting, and high temperature of use environments of electric and electronic devices, these demand characteristics are increasing. Particularly, since a demand for thinning of copper or copper alloy used for automobile parts and parts for electric and electronic devices is increasing, the required strength level is becoming higher.

In addition, low flexural modulus is required as one of the characteristic items required for copper alloy materials used for electric / electronic devices and automobile parts. In recent years, along with the progress of miniaturization of connectors and vehicle parts, dimensional accuracy of terminals and tolerances of press working have become strict. By reducing the bending coefficient of the material, the influence of the dimensional fluctuation on the contact pressure of the contact portion can be reduced, so that the design is facilitated.

In addition, materials used for parts such as connectors, terminals, lead frames, relays, switches, etc. constituting on-vehicle parts and electric / electronic parts can withstand the stress applied during assembly or operation of on- High strength is required.

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

As a strengthening method for a copper alloy, there is a precipitation strengthening method for precipitating a fine second phase in a material. This strengthening method is performed in a large number of alloy systems because it has an advantage of simultaneously increasing the strength and improving the conductivity. However, with the recent miniaturization of electric and electronic apparatuses and automotive vehicle parts, the copper alloy is subjected to a bending process with a small radius by a material having a higher strength, and a copper alloy plate material having excellent bending workability is strongly Is required. In addition, it is not preferable that the plate material having high strength, high spring hardness and good bending workability has a characteristic difference in the rolling parallel direction (RD, rolling direction) and the rolling vertical direction (TD, width direction) It is important to show. Particularly, when used as a very small terminal, it is important that fine processing is performed in a pin-like shape with a narrow width and good characteristics are exhibited here in both the rolling parallel direction and the direction perpendicular to the rolling direction. In the conventional Cu-Ni-Si based copper alloy, in order to obtain high strength, a large work hardening is achieved by increasing the rolling rate. However, this method deteriorates the bending workability as described above, and it is difficult to achieve both high strength and good bending workability.

BACKGROUND ART In recent years, terminals, connectors, vehicle-use terminals, and the like for electric and electronic devices have been bending at a radius smaller than ever and processed into complicated shapes with the miniaturization of the entire module and the increase in the density of electrical components. A complicated machining with a small bending radius is entered in both cases where the axis of bending is vertical (GW bending) or parallel (BW bending) in the rolling direction and the spring characteristics (contact pressure and bending amount) shall. Conventionally, when a plate material of a callus-type alloy (Cu-Ni-Si alloy) is processed and used as a contact portion of a terminal, only a specific direction (GW or BW) is processed. However, in recent years, since it is processed into a complicated shape as described above, it is designed so that a large number of GW bending BW bending occurs at one terminal. In this case, a conventional material having an anisotropy of bending strength and work hardening index can not be used as a terminal or a connector if cracks are generated in either GW or BW bending. Further, if there is anisotropy, the spring characteristics after machining will also vary depending on the bending direction, making it unusable as a terminal or a connector.

Conventionally, there are several proposals to be solved by controlling the work hardening index and crystal orientation with respect to the demand for improvement in the bending workability. For example, Patent Document 1 discloses a method of measuring a tensile strength, a proof stress, a uniform elongation, and a tensile strength in a rolling parallel direction (LD) and a direction perpendicular to a rolling direction (TD) in a Cu- It is proposed to improve the bending workability of GW and BW by controlling the total elongation and work hardening index. Further, in Patent Document 2, it is proposed that the bending workability is improved by controlling the crystal orientation and the work hardening index of the Cu-Ni-Si based alloy. In Patent Document 3, it has been proposed that both the strength and the bending workability can be achieved by controlling the Cube bearing area ratio to 10% or more.

Japanese Laid-Open Patent Publication No. 2010-031379 Japanese Laid-Open Patent Publication No. 2013-047360 Japanese Laid-Open Patent Publication No. 2011-117034

In the invention described in Patent Document 1, by controlling the mechanical characteristics in the rolling parallel direction and the rolling vertical direction, excellent characteristics in which the balance between the strength and the bending workability are matched are obtained. However, the control of the crystal orientation and the crystal grain size is not described. In the invention described in Patent Document 2, the crystal orientation and the work hardening index are controlled so that both the strength and the bending workability are maintained. However, the anisotropy in the rolling parallel direction and the direction perpendicular to the rolling direction is not controlled, and the respective crystal orientations are controlled, but there is no description about the distribution in the sheet thickness direction. Patent Document 3 improves the bending workability by integration of the Cube bearing surface area ratio. However, the control of the work hardening index is not performed, and the anisotropy in both the rolling parallel direction and the rolling vertical direction is not controlled.

In view of the problems of the prior art as described above, it is an object of the present invention to provide a bending tool which is excellent in bending workability, has excellent strength, has a low bending coefficient as spring characteristics after bending, A leadframe, a connector, and a terminal for high-quality electrical and electronic devices capable of complicated machining that performs both GW bending and BW bending with respect to one member having little anisotropy in the direction parallel to the rolling direction and in the direction perpendicular to the rolling It is an object of the present invention to provide a copper alloy sheet material suitable for a connector, an end member, a relay, a switch, a socket or the like for a vehicle or the like.

The inventors of the present invention have repeatedly studied copper alloy sheets suitable for use in electric and electronic parts and automotive vehicle parts which have greatly improved bending workability and strength in a copper alloy sheet of a Cu-Ni-Si alloy, As a result of the investigation, it was found that there is a correlation between the work hardening index, bending workability and strength and anisotropy of these. It has also been found that both the bending process and the strength anisotropy can be lowered by appropriately controlling the relationship between the rolling parallel direction of the plate material and the work hardening index in the rolling direction. It has been further investigated that bending workability and anisotropy thereof can be improved by appropriately controlling the texture. The present invention has been completed on the basis of these discoveries.

That is, according to the present invention, means described below are provided.

(1) A steel sheet comprising at least one member selected from the group consisting of B, Mg, P, Cr, Mn, Fe, Co, Zn, Zr, Ag and Sn containing 1.0 to 6.0 mass% of Ni and 0.2 to 2.0 mass% (B, Mg, P, Cr, Mn, Fe, Co, Zn, Zr, Ag and the like) in a total amount of 0.000 to 2.000 mass%, and the balance of copper and inevitable impurities. Sn may be an arbitrary additive component which may contain any one or more species and may not contain any species)

The work hardening index n _RD in the rolling parallel direction _RD is 0.010 to 0.150,

N ratio _RD / _TD n of the work hardening exponent n _TD of the work-hardening exponent n in the rolling parallel direction _RD and rolling the vertical direction (TD) is a 0.500 ~ 1.500,

The depth of the copper alloy sheet material in the thickness direction from the surface of the rolled surface of the copper alloy sheet material is D and the depth of the copper alloy sheet material in the depth direction D parallel to the surface of the rolled surface The average value Sa of S (D) in the plate thickness direction is in the range of from 5.0 to 20% when the area ratio of the crystal grains having a stagger angle from the Cube orientation {001} < 100 & By weight, based on the total weight of the copper alloy sheet.

(2) A method for producing a magnetic recording medium according to item (1), which comprises 0.005 to 2.000 mass% in total of at least one selected from the group consisting of B, Mg, P, Cr, Mn, Fe, Co, Zn, Zr, Copper alloy sheet.

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

(4) The flexural modulus in both the rolling parallel direction and the rolling direction is less than 140 GPa, and the ratio E _RD / E _TD of the flexural modulus in the rolling parallel direction (E _RD ) to the flexural modulus in the vertical direction (E _TD ) is 1.05 Or less of the copper alloy sheet.

(5) A connector comprising the copper alloy sheet according to item (1).

(6) A method for producing a copper alloy sheet material according to item (1)

Each process of melting and casting process, ingot rolling process, homogenization heat treatment process, hot rolling process, quenching process, cold rolling 1 process, slit and trimming process, cold rolling 2 process, intermediate solution treatment process, quenching process, aging heat treatment process In this order,

In the ingot rolling process, the rolling process per pass is performed at least once at a machining rate of 1.0% or more,

In the cold rolling step, the average rolling pressure per pass is 50 N / mm &lt; ² &gt; or more so that the total machining ratio is 30% or more,

In the cold rolling step 2, the average rolling pressure per pass is 50 N / mm &lt; ² &gt; or more so that the total processing rate is 50%

Wherein the solution treatment is carried out in a high temperature region at a temperature rising rate of 5 占 폚 / sec or more and an arrival temperature of 600 to 1100 占 폚 in the intermediate solution treatment step.

(7) The method for producing a copper alloy sheet material according to (6), wherein the aging and polishing step, the cold rolling step, and the final annealing step are performed in this order after the aging heat treatment step.

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

The copper alloy sheet material of the present invention has excellent bending workability, exhibits excellent strength, and has small anisotropy in the rolling parallel direction and the vertical direction in the rolling characteristics of bending workability and strength. Therefore, the copper alloy sheet material of the present invention can be used as a lead frame, a connector, and a terminal for electrical and electronic devices, as well as connectors and end parts for automotive vehicle components, a copper alloy having properties particularly suitable for relays, switches, It is plate.

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

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

A preferred embodiment of the copper alloy sheet material of the present invention will be described. The term &quot; plate material &quot; in the present invention also includes &quot; plaster material &quot;.

In the present invention, by properly controlling the work hardening index in the rolling parallel direction of the plate and in the direction perpendicular to the rolling direction, the bending workability can be improved while the strength is increased.

Generally, strain is accumulated in a metal structure (crystal) by plastic deformation to a metal material, work hardening occurs, and the material strength (proof stress, tensile strength) is increased. Here, the larger the work hardening index of the metal material, the greater the increase in strength due to the 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 the plastic deformation such as the bending work or the press work, and is less affected by the machining. That is, when the amount of deformation is made the same, a material having a large work hardening index tends to have high strength.

In this regard, for example, in the bending process for a terminal or a connector, the amount of plastic deformation is large in the vicinity of the apex portion of the bending, as compared with other portions. Therefore, if a relatively high-work hardening index material is treated by bending, the amount of work hardening becomes large, and high strength is likely to occur. In general, when the material becomes high in strength, the bending workability tends to deteriorate. For this reason, when the strength of the terminal or the bending surface of the connector is locally increased, cracks are generated from the point where the strength is increased. For this reason, in order to obtain good bending workability, it is necessary to control the work hardening index to a certain value or less. Particularly, in recent connectors for electric / electronic devices and connectors for vehicle parts, as described above, either GW bending in which the axis of bending is perpendicular to the rolling direction and BW bending in which the axis of bending is parallel to the rolling direction It is preferable to appropriately control the work hardening indices in both the rolling parallel direction of the plate material and the vertical direction of the rolling.

Further, in the present invention, in addition to the above control of the work hardening index, the aggregate structure state of the copper alloy sheet material is also controlled. Specifically, the thickness of the copper alloy sheet is t, the depth in the thickness direction from the surface of the rolled surface of the copper alloy sheet is D, and the copper alloy sheet is parallel to the surface of the rolled surface at the depth D The average value Sa of S (D) in the plate thickness direction is set to 5.0 (D), where S (D) is the area ratio of crystal grains having a deviation angle of 15 DEG or less from the Cube orientation {001} < 100 & To 30.0%, the bending workability is improved while maintaining the material strength, and the anisotropy thereof is also reduced. Thus, by controlling the work hardening index and the aggregate structure, the coefficient of flexure is also excellent as the spring characteristics after the bending process.

[Alloy Composition]

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

(Essential Additive Elements)

The content of Ni and Si required for the copper alloy constituting the plate material of the present invention and the operation thereof are shown.

(Ni)

Ni is contained together with Si to be described later to form a Ni ₂ Si phase precipitated by the age precipitation heat treatment, thereby contributing to the improvement of the strength of the copper alloy sheet material. The Ni content 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 content of Ni within the above range, the Ni ₂ Si phase can be appropriately formed and the mechanical strength (tensile strength or 0.2% proof stress) of the copper alloy sheet material can be increased. Also, the conductivity is high. The hot rolling workability is also good.

(Si)

Si is contained together with the Ni to form a Ni ₂ Si phase precipitated by the age precipitation heat treatment to contribute to the improvement of the strength of the copper alloy sheet material. The Si content is 0.20 to 2.00 mass%, preferably 0.25 to 1.90 mass%, and more preferably 0.50 to 1.70 mass%. When the content of Si is set to Ni / Si = 4.2 by the stoichiometric ratio, the balance between the conductivity and the strength is the best. Therefore, the content of Si is preferably such that Ni / Si is in the range of 2.50 to 7.00, and more preferably 3.00 to 6.50. By setting the Si content within the above range, the tensile strength of the copper alloy sheet material can be increased. In this case, excess Si is solid-solved in the matrix of copper, so that the conductivity of the copper alloy sheet material is not lowered. In addition, casting at the time of casting, hot rolling and cold rolling workability are good, and casting cracks and rolling cracks do not occur.

(Additive element)

Next, the types of additive elements in the copper alloy constituting the plate material of the present invention and their addition effects will be described. Preferred examples of the additive element include B, Mg, P, Cr, Mn, Fe, Co, Zn, Zr, Ag and Sn. The total content of these elements in an amount of 3.000 mass% or less is preferable because it does not cause harmful effects that lower the electric 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% in order to fully utilize the effect of the addition and not to lower the conductivity. The effect of addition of each element is shown below.

(Mg, Sn, Zn)

Mg, Sn and Zn are added to improve stress relaxation resistance. The stress relaxation property is further improved by the synergistic effect when the components are added together rather than when they are added together. Further, there is an effect that remarkable improvement of the solder brittleness is obtained. The content of each of Mg, Sn and Zn is preferably 0.00 to 2.00 mass%, more preferably 0.10 to 1.80 mass%.

(Mn, Ag, B, P)

Addition of Mn, Ag, B and P improves hot workability and improves strength. The content of each of Mn, Ag, B and P is preferably 0.001 to 1.00 mass%, more preferably 0.050 to 0.70 mass%.

(Cr, Zr, Fe, Co)

Cr, Zr, Fe, and Co are precipitated finely in a compound or a single form, and contribute to precipitation hardening. In addition, as the compound, it is precipitated in a size of 50 to 500 nm and has an effect of suppressing the grain growth to have a fine grain size, and to improve the bending workability. The content of each of Cr, Zr, Fe and Co is preferably 0.001 to 1.50 mass%, 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 _RD in the rolling parallel direction of the plate material is preferably 0.01 or more and 0.15 or less, preferably 0.01 or more and 0.10 or less, more preferably 0.01 or more and 0.08 or less, Or less.

The work hardening index n _TD in the direction perpendicular to the rolling direction of the plate is preferably 0.01 or more and 0.15 or less, more preferably 0.01 or more and 0.10 or less, still more preferably 0.01 or more and 0.08 or less, particularly preferably 0.01 or more and 0.06 or less .

The ratio n _RD / n _TD to the work hardening index n _TD in the rolling vertical direction of the work hardening index n _{RD in} the rolling parallel direction is 0.50 to 1.50, preferably 0.70 to 1.40, more preferably 0.75 to 1.35, More preferably from 0.80 to 1.30. By controlling the work hardening index to the above value, it becomes easy to control the Cube bearing surface area ratio.

The reason why the work hardening index is set in this range is that the work hardening index is controlled to be a certain value or less so that the amount of work hardening at the time of bending of the terminal becomes relatively small and good workability tends to be obtained.

[Set organization]

In the copper alloy sheet material of the present invention, the thickness of the copper alloy sheet material is t, the depth in the sheet thickness direction from the surface of the rolled surface of the copper alloy sheet material is D, and the copper alloy sheet material is the rolled surface The average value of S (D) in the plate thickness direction when the area ratio of the crystal grains having the stagger angle from the Cube orientation {001} < 100 & Sa is not less than 5.0% and not more than 30.0%. For analysis of the Cube orientation, the crystal orientation analysis in the EBSD measurement is used. Also, the area ratio of the crystal grains within the inclination angle of 15 DEG (inclusive of 0 DEG) from the Cube orientation {001} < 100 > means the area ratio of the Cube orientation. This means the ratio of the area of the crystal grain within the range of the inclination angle of 15 占 within the Cube orientation to the total area of the entire surface when the surface is observed in 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 direction perpendicular to the rolling direction (the width direction) TD, and the direction normal to the rolling surface (the thickness direction) ND. In addition, the main surface of the plate of the copper alloy sheet material is referred to as the rolled surface 2. Fig. 2 shows a surface 3 parallel to the surface of the rolled surface at the depth D of the copper alloy sheet material.

The copper alloy sheet material is usually produced by repeating rolling, and has a texture associated with the rolling direction and the like. Represent this organization as a standard axis with RD, TD, and ND perpendicular to each other. The crystal grains of the Cube orientation {001} < 100 > according to the present invention are such that the {001} plane of the crystal is perpendicular to the ND, and the crystal orientation of the crystal in the <100> direction Indicates a state parallel to RD.

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

However, it is physically difficult to calculate Sa by measuring the area ratio S (D) of the Cube bearing on all the surfaces from the copper alloy sheet surface (D = 0) to the back surface (D = t). Therefore, in the present invention, five or more depths D1, D2, ... S (D1), S (D2), ... And Sa is calculated by calculating the average of these values. Particularly, it is preferable to adopt five kinds of depths D: D = 1 / 20t, 1 / 4t, 1 / 2t, 3 / 4t and 19/20t. It is also preferable to select a plurality of depths D with respect to the center of the plate thickness (D = 1 / 2t) in the plate thickness direction.

Hereinafter, the average value Sa of the area ratio is also referred to as &quot; the average value of the area ratio of the Cube orientation in the plate thickness direction &quot;. The average value of the area ratio of the Cube orientation in the plate thickness direction is preferably 8.0% or more and 30.0% or less. By controlling Sa to 5.0% or more, bending workability can be improved. This is considered to be because the generation of a shear band generated in the bending process can be suppressed. In the same way for the thickness direction in the bending process, the Cube bearing area ratio is set to 5.0% or more, which can suppress the occurrence of shear zones accompanying compressive deformation. Further, by controlling the Cube bearing area ratio in the vicinity of the center of the plate thickness to 5.0% or more, it is possible to suppress the development of cracks along with the deformation as well as the front and back surfaces. Therefore, each value of the area ratio S (D) of the crystal grains having the 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)

In order to investigate the distribution in the thickness direction of the area ratio of the cubic bearing crystal grains in the copper alloy, measurement is carried out by changing the polishing amount. In order to observe the texture in the plate thickness direction, one side of the test piece is masked and only the opposite side is electrolytically polished. At this time, the polishing is performed while paying attention to the fact that the surface of the test piece is mirror-finished. In practice, it is understood that the fine structure of the polishing can be grasped by fine adjustment of the amount of polishing by electrolytic polishing, and detailed analysis can be performed by EBSD analysis. The prepared specimen is scanned in the range of 300 μm × 300 μm in 0.1 μm steps by the orientation analysis by EBSD, and the area ratio of the cubic bearing crystal grains is measured.

(EBSD method)

The EBSD method is used for the analysis of the crystal orientation in the present invention. The EBSD method is an abbreviation of Electron Back Scatter Diffraction. It is a crystal orientation analysis technique using reflected electron Kikuchi line diffraction which occurs when a sample is irradiated with an electron beam in a scanning electron microscope (SEM). The sample area of 300 mu m x 300 mu m including 200 or more crystal grains is scanned in 0.1 mu m steps and the crystal orientation of each crystal grain is analyzed. The measurement area and the scanning step are set to 300 × 300 μm and 0.1 μm from the grain size of the sample. The area ratio of each orientation can be obtained as the ratio of the area of the crystal grains having the normal to the crystal grain within the range of ± 15 ° from the ideal orientation of the Cube orientation {001} <100> to the entire measurement area of the obtained area have. The information obtained by the orientation analysis by the EBSD includes azimuth information to the depth of several tens of nm at which the electron beam penetrates the sample. Since this is sufficiently small for the area to be measured, the area ratio is described in this specification. For analysis of EBSD measurement results, OIM Analysis (product name) is used.

[Production method of copper alloy sheet]

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

The conventional precipitation-type copper alloy manufacturing method is characterized in that the ingot is obtained by dissolving and casting a copper alloy material [step 1], followed by homogenizing heat treatment [step 3], hot rolling [step 4], water cooling [step 5] And cold rolling [step 7] are carried out in this order to form a thin plate, and intermediate solution treatment [Step 10], aging precipitation heat treatment [step 11] and finish cold rolling [step 13]. Further, the final annealing for removing the strain after the finish cold rolling [Step 13] [Step 14] is also performed. Further, between the aging precipitation heat treatment [step 11] and the finish cold rolling [step 13], an oxide film removing step (acid cleaning / polishing [step 12]) may be introduced. In this series of processes, the texture of the material is finally determined by the recrystallization occurring during the intermediate solution treatment, and finally determined by the rotation of the orientation occurring during finish cold rolling.

On the other hand, in the method of the present invention, the average value Sa of the Cube bearing area ratio in the plate thickness direction and the work hardening indices in both the rolling parallel direction and the rolling vertical direction are controlled One copper alloy sheet is produced.

Specifically, in the present invention, the melting and casting process 1, the ingot rolling process 2, the homogenization heat treatment process 3, the hot rolling process 4, the water cooling process 5, the roughing process 6, Cold rolling 1 [Step 7], slit and trimming [Step 8], cold rolling 2 [Step 9], intermediate solution treatment [Step 10], water cooling [Step 10-2], aging precipitation heat treatment [Step 11] Cleaning and polishing [step 12], cold rolling 3 [step 13], and final annealing [step 14]. If the desired sheet material is obtained, the above-mentioned pickling and polishing (step 12), cold rolling 3 [step 13] and final annealing [step 14] may be omitted.

In the melting and casting [Step 1], an ingot is obtained by adding a predetermined additive element. The cooling rate at the time of casting is usually 0.1 to 100 ° C / second.

Next, in the ingot rolling [Step 2], a certain cold rolling is applied to the ingot to partially recrystallize in the vicinity of grain boundaries during the homogenization heat treatment, and in the subsequent recrystallization in the intermediate solution formation, ). &Lt; / RTI &gt; The rolling rate per pass in the ingot rolling [step 2] is 1.0% or more (preferably 5.0% or less), and the number of passes is one or more times.

Next, homogenization heat treatment [Step 3] is performed so that the holding temperature is 800 ° C or higher and 1100 ° C or lower and the holding time is 5 minutes to 20 hours. Thereafter, hot rolling (step 4) is performed in multiple passes to a predetermined plate thickness in a processing temperature range of 1100 占 폚 or lower (preferably 800 占 폚 or higher), and cooling (quenching , So-called quenching). Thereafter, the surface of the hot rolled material is subjected to a surface finish [step 6] to remove the oxide film, followed by cold rolling 1 [step 7].

In cold rolling 1 [Step 7], cold rolling is performed in several to several passes so that the total rolling processing rate becomes 30% or more (preferably 60% or less). The average rolling pressure during rolling per 1 rolling pass is controlled to 50 N / mm ² or more in order to grow a certain Cube bearing crystal grain during recrystallization and to control the work hardening index.

Next, in order to trim the shape of the material end portion during cold rolling, a slit [Step 8] is performed to remove unnecessary ends of the material by trimming.

Thereafter, in the cold rolling 2 [Step 9], cold rolling is performed in several to several passes such that the total rolling processing rate becomes 50% or more (preferably 80% or less). Here too, the average rolling pressure during rolling per one rolling pass is controlled to 50 N / mm ² or more in order to grow the Cube bearing crystal grains during recrystallization and to control the work hardening index.

Thereafter, the solute element is solidified at a temperature elevation rate of 5.0 DEG C / sec or more and a temperature of 600 to 1100 DEG C in the intermediate solution treatment [step 10], and the solution is heated for a predetermined time (preferably 1 second to 5 hours) Thereby forming crystal grains of Cube orientation along with grain growth. In the cold rolling 1 and the cold rolling 2 before the intermediate solution treatment process [Step 10], the processed structure is once formed, but by performing the recrystallization in this intermediate solution treatment process [Step 10], the following equiaxed crystal grains . When the temperature and time of arrival are satisfied, water cooling (so-called quenching) is performed rapidly (step 10-2).

Thereafter, the strength required for the aging precipitation heat treatment [step 11] at a holding temperature of 400 to 700 ° C and a holding time of 5 min to 10 h is satisfied.

Thereafter, acid cleaning and polishing (step 12) is performed to remove the oxide film on the surface of the plate material, if necessary. Thereafter, if necessary, final finish rolling is performed in cold rolling 3 [Step 13]. Even when cold rolling 3 [Step 13] is carried out to maintain equiaxed grains formed in the intermediate solution treatment process [Step 10], the rolling process rate is as low as possible at 1.0% or more. The upper limit of the rolling processing rate in this cold rolling 3 [Step 13] is preferably 40% or less.

Thereafter, if necessary, final annealing (tempering annealing) is carried out at 200 to 700 ° C for 1 minute to 5 hours. [Step 14] The strain inside the plate material is removed. This final annealing is also referred to as strain removal annealing.

Hereinafter, preferable conditions of each step will be described in more detail.

In the ingot rolling [Step 2], cold rolling is applied to the ingot, nucleation occurs in the vicinity of grain boundaries at the time of reheating (reheating) in the homogenization heat treatment in the next step, and further, Thereby contributing to the formation of equiaxed crystal grains. Here, the cold rolling rate per pass is 1.0% or more, and the number of passes is one or more times. Preferably, the cold rolling rate per pass is not less than 2.0% and the number of passes is not less than three times, more preferably not less than 3.0% per pass, and not less than five passes.

In cold rolling 1 [Step 7], in order to control the Cube bearing surface area ratio and the work hardening index at the time of recrystallization in the subsequent intermediate solution processing [Step 10], the total processing ratio is set to be not less than 30% Several tens of passes are performed, and the average rolling pressure per pass is controlled to 50 N / mm ² or more. Preferably, the average rolling pressure is at least 60 N / mm ^2, more preferably at least 70 N / mm ^2.

In cold rolling 2 [Step 9], similarly to cold rolling 1 [Step 7], in order to control the Cube bearing surface area ratio and the work hardening index at the time of recrystallization in the subsequent intermediate solution processing [Step 10] Rolling of several to several passes is performed so that the machining rate becomes 50%, and the average rolling pressure per pass is controlled to 50 N / mm ² or more. Preferably, the average rolling pressure is at least 60 N / mm ^2, more preferably at least 70 N / mm ^2.

In the subsequent intermediate solution treatment (step 10), the average particle size (dimension) a in the rolling parallel direction and the average grain size (dimension) in the rolling direction are different from each other by the recrystallization in the high temperature region at a temperature raising rate of 5 deg. C / sec or more and an arrival temperature of 600 to 1100 deg. Of the average particle diameter b is 0.8 or more. Since the crystal grains of the equiaxed crystals are large, the anisotropy of the work hardening index is reduced. Preferably, the grain size ratio a / b of the grain is 0.85 or more, more preferably 0.9 or more (preferably 1.1 or less). Since the machining rate of the cold rolling 3 after the intermediate solution treatment is small, the crystal grain size of the base material of the copper alloy sheet material of the present invention can be reduced to the range of the condition of the cold rolling 3 [Step 13] .

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

Processing rate (%) = {(t1-t2) / t1} x 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 plate of the present invention is not particularly limited, but is preferably 0.04 to 0.50 mm, and more preferably 0.05 to 0.45 mm.

[Properties of copper alloy sheet]

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

In the 180 ° U bending test in which the bending workability is R / t = 1.0, which is expressed by the bending radius R and the plate thickness t, the bending axis is in a vertical direction (GW bending) parallel to the rolling direction (BW bending) , It is preferable that no crack occurs on the surface after the bending process. In addition, even when a narrow specimen with a width of 1.0 mm or less is similarly treated with 180 ° U bending at R / t = 1.0, cracks are formed on the surface after any bending, such as GW bending and BW bending It is more preferable to have a bending workability that does not occur.

The tensile strength TS of the plate material is preferably 650 MPa or more in both the tensile strength TS-RD in the rolling direction RD and the tensile strength TS-TD in the rolling direction TD Do. The ratio TS-RD / TS-TD of these is preferably 1.10 or less, more preferably 1.08 or less. The upper limit of the tensile strength is not particularly limited, but is, for example, 1020 MPa or less.

The 0.2% proof stress (YS) of the plate is preferably 600 MPa or more in both of the 0.2% proof stress (YS-RD) in the parallel direction of the plate and the 0.2% proof stress (YS-TD) in the normal direction. Further, the ratio of these 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, but is, for example, 1000 MPa or less.

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

The conductivity is preferably 20.0% ICAS or more. Here, "% IACS" is the resistivity 1.7241 × 10 international standard works (International Annealed Copper Standard) ^- shows the conductivity in the case where the ⁸ Ωm as 100% IACS. The upper limit of the conductivity is not particularly limited, but is, for example, 50% IACS or less.

Detailed measurement conditions of each characteristic are as described in the examples unless otherwise specified.

[Example]

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

(Examples 1 to 16 and Comparative Examples 1 to 14)

With respect to each of the examples and the comparative examples, an alloy material containing the respective amounts of Ni, Si, and auxiliary addition elements as shown in Table 1, and the balance of Cu and unavoidable impurities was dissolved in a high frequency melting furnace, This was cooled at a cooling rate of 0.1 ° C / sec to 100 ° C / sec and casting [Step 1] was conducted to obtain ingot.

This ingot was subjected to the ingot rolling [Step 2] which cold-rolled the ingot at a machining rate of 1.0% or more and at least one pass. Thereafter, the ingot was subjected to homogenization heat treatment [Step 3] at 800 ° C or more and 1100 ° C or less for 5 minutes to 20 hours. Thereafter, hot rolling as hot working [Step 4] was performed at 800 ° C or higher and 1100 ° C or lower, and quenching and cooling for water [Step 5] were performed to obtain hot-rolled plates. Next, the surface of this hot-rolled plate was subjected to surface machining [step 6] to remove the oxide film. Thereafter, in cold rolling 1 [Step 7], the steel sheet was rolled in several to several passes so that the total machining ratio was 30% or more. The average rolling pressure per pass at this time was 50 N / mm ² or more. Then, both ends of the rolled material were slit (Step 8). Thereafter, in the cold rolling 2 [Step 9], the rolling was performed in several to several passes so that the total machining ratio was 50% or more, and the average rolling pressure per pass was 50 N / mm ² or more. Thereafter, in the intermediate solution treatment process [Step 10], heat treatment is carried out at a temperature rising speed of 5 ° C / sec or more and a final temperature of 600 to 1100 ° C for 1 second to 5 hours, followed by quenching [Step 10-2 ]did. Here, by recrystallization in the high-temperature region, the ratio of the dimension a in the rolling parallel direction to the dimension b in the rolling direction, a / b is 0.8 or more, and isometric grains are obtained. Thereafter, the required strength was obtained in the aging precipitation heat treatment [step 11] at a holding temperature of 400 to 700 ° C and a holding time of 5 min to 10 h. Thereafter, acid cleaning and polishing [step 12] were performed to remove the oxide film on the surface of the plate material. Thereafter, in the cold rolling 3 [Step 13], final finish rolling was performed. Cold rolling 3 [Step 13] was performed at a rolling processing rate as low as possible at 1.0% or more in order to maintain equiaxed particles formed in the intermediate solution treatment [Step 10]. More specifically, the rolling processing rate in the cold rolling 3 [Step 13] was 1.0 to 40.0%. Thereafter, in the final annealing [step 14] in which the temperature was maintained at 200 to 700 ° C for 1 minute to 5 hours, the strain inside the plate material was removed.

As shown in Table 2, the manufacturing conditions of each of the examples and the comparative examples are shown in the column of &quot; Process X &quot; (where X is the number of the process).

Thus, a copper alloy plate having a final plate thickness t of 0.15 mm was obtained.

The following properties were examined for each disclosure material.

(a) Work hardening index [n value]

With respect to the specimens of each of the examples and comparative examples, the work hardening index was measured by the slope of the plastic strain area of the stress strain curve in the tensile test of the JIS No. 5 test piece. The tensile test was carried out in accordance with JIS Z 2241. The evaluation criterion is that the work hardening index (n _RD ) in the rolling parallel direction satisfies 0.010 to 0.150, the work hardening index (n _TD ) in the vertical direction of rolling is 0.010 to 0.150, the work hardening index n in the rolling parallel direction _RD) and the rolling ratio n _RD / _TD n of work hardening index (n _TD) in the vertical direction and the 0.500 ~ 1.500 to pass, it was to fail to a departure from the scope.

(b) Cube bearing area ratio

The crystal orientations of the specimens of each of the Examples and Comparative Examples were measured by the EBSD method under the conditions of a measurement area of 300 mu m x 300 mu m and a scan step of 0.1 mu m. In the analysis, the EBSD measurement result of 300 mu m x 300 mu m was divided into 25 blocks, and the area ratio of the grains having the Cube orientation of each block was confirmed as follows. The electron beam was the source of the thermal electrons from the W filament of the scanning electron microscope. The measurement device of the EBSD method was OIM 5.0 (product name) manufactured by TSL Solutions Co., Ltd. and OIM Analysis was used for analysis.

In polishing prior to EBSD measurement, the target tissue was exposed by electrolytic polishing in order to observe the structure. 5 parts of depth d = 1 / 20t, 1 / 4t, 1 / 2t, 3 / 4t and 19 / 20t with respect to the plate thickness t was observed with EBSD. The occupation rates (i.e., area ratios) of the Cube orientation grains with respect to the measurement visual field were obtained at all five locations. Then, the average value Sa of the area ratios at these five locations is obtained and expressed as "average value (%) in the plate thickness direction of the Cube bearing area ratio" in the table.

(c) 180 ° U bend test

The specimens of each of the examples and comparative examples were pressed in parallel with the rolling vertical direction test piece punched by a press so that the width was 0.25 mm and the length was 1.5 mm perpendicularly to the rolling direction. Were provided for the test. BW (Bad Way) was obtained by bending W so that the axis of bending was perpendicular to the direction of rolling in the direction parallel to the rolling direction, GW (Good Way) ) Was subjected to 90 ° W bending according to the Japanese Industrial Standard of JCBA-T307 (2007), and then subjected to 180 ° bending without applying an inner radius by a compression tester. The bending surface was observed with a scanning electron microscope of 100 times and the presence of cracks was examined. "A" indicates that there was no crack, "D" indicates that there was a crack, and "D" indicates "crack". When a crack occurred, the maximum size of the crack was 30 μm to 100 μm and the maximum depth was 10 μm or more.

(d) Tensile strength [TS]

The test specimens of each of the examples and comparative examples were subjected to a tensile test in which the test specimens were punched by a press to have a width of 0.25 mm and a length of 1.5 mm perpendicularly to the rolling direction, ). Separately, a rolling parallel direction test piece punched by a press so as to have a width of 0.25 mm and a length of 1.5 mm in parallel in the rolling direction was provided to the tensile test to obtain the tensile strength in the rolling parallel direction (TS-RD). The tensile strength was measured based on JIS Z 2241.

The anisotropy of the tensile strength in the rolling parallel direction and in the rolling direction was confirmed. TS passed 600 MPa or more, and TS was less than 600 MPa.

(e) Conductivity [EC]

The resistivity was measured by a four-terminal method in a thermostatic chamber maintained at 20 ° C (± 0.5 ° C) to calculate the conductivity. The distance between the terminals was set to 100 mm. EC has passed 20% IACS or higher, and TS has dropped below 20% IACS.

(f) Flexural modulus [E]

From the test specimens of each of the examples and the comparative examples in accordance with the Japanese Industrial Standard of Joint Venture Standard JCBAT 312, test specimens perpendicular to the direction of rolling were punched by a press to have a width of 0.25 mm and a length of 1.5 mm perpendicularly to the rolling direction The coefficient (E _TD ) was obtained. Separately, the rolling parallel direction flexural modulus (E _RD ) was determined from the rolling parallel direction test piece punched by a press so as to have a width of 0.25 mm and a length of 1.5 mm in parallel in the rolling direction. Sampling was taken from five locations in the width direction of the coil, and an average value of the results of the measurements was taken.

Each 180 ° U bend test piece was fixed to a jig, and the test piece was pushed ten times, and an average value of the displacement (pushing depth) f and the stress w was obtained.

The flexural modulus E (GPa) is expressed by the following equation (1).

E = 4 a / b x (L / t) 3 ... (One)

where a is the displacement (pushing depth), the slope of the stress w, b is the width of the specimen, L is the distance between the fixed end and the load point, and t is the thickness of the specimen. The fixed end in L was the apex of the bend.

And the anisotropy in the direction parallel to the rolling direction and the direction perpendicular to the rolling direction of the flexural modulus was confirmed. E passed 110 GPa, and E failed to pass 110 GPa.

(g) 0.2% proof load [YS]

0.2% yield (YS-TD) in the vertical direction in the direction perpendicular to the rolling direction was obtained from the test specimens perpendicular to the direction of rolling by punching the specimens of each of the examples and the comparative examples so as to have a width of 0.25 mm and a length of 1.5 mm perpendicularly to the rolling direction. Separately, a 0.2% yield strength (YS-RD) in the rolling parallel direction was obtained from the rolling parallel direction test piece punched by a press so that the width was 0.25 mm in parallel and 1.5 mm in length in parallel in the rolling direction.

In measuring the flexural modulus, a 0.2% proof stress Y (MPa) was calculated from the following equation (2) from the push-in amount (displacement) to the elastic limit of each test piece.

Y = {(3E / 2) x t (f / L) x 1000} / L (2)

E is the flexural modulus, t is the plate thickness, L is the distance between the fixed end and the load point, and f is the displacement.

The anisotropy of the rolling parallel direction and the rolling direction of the 0.2% proof stress was confirmed. YS passed 600 MPa or more, and YS was less than 600 MPa.

From the results shown in Table 2, it can be seen that the samples of the respective examples according to the present invention are excellent in bending workability, tensile strength, 0.2% proof stress, conductivity and flexural modulus. In the bending workability, in the 180 占 bending test, cracks did not occur at the top of the bend. In particular, the bending workability, the tensile strength, the 0.2% proof stress, the electric conductivity and the flexural modulus were small in the anisotropy in the rolling parallel direction and the direction perpendicular to the rolling direction.

Therefore, the copper alloy sheet material of the present invention is suitable as a copper alloy sheet material suitable for connectors, end parts, relays, switches, sockets, etc. for lead frames, connectors,

On the other hand, from the results shown in Table 2, it can be seen that the properties of any one of the samples of the comparative examples were deteriorated.

Comparative Examples 1 to 7 are examples of tests manufactured outside the manufacturing conditions specified in the present invention. In Comparative Examples 1 to 7, both of the work hardening index and the average value Sa of the Cube bearing surface area ratio were out of the range specified in the present invention. In Comparative Examples 2 to 7, the bending workability was inferior. In Comparative Examples 1 to 7, both the tensile strength, the 0.2% proof stress, the conductivity, and the flexural modulus greatly decreased in the rolling parallel direction and in the perpendicular direction.

In addition, Comparative Examples 8 to 14 are test examples deviating from the alloy composition prescribed in the present invention. In Comparative Examples 8 to 14, all the average values Sa of the Cube bearing area ratios were out of the range specified in the present invention. In Comparative Examples 8 to 14, the bending workability, the tensile strength, the 0.2% proof stress, the conductivity and the flexural modulus were at least one or more, including the rolling parallel direction and anisotropy in the direction perpendicular to the rolling direction.

While the present invention has been described in conjunction with the embodiments thereof, it is to be understood that the invention is not limited to any details of the description thereof except as specifically set forth and that the invention is broadly construed broadly I think it is natural to be interpreted.

The present application claims priority based on Japanese Patent Application No. 2014-112974, filed on May 30, 2014, which is herein incorporated by reference as its description.

1: Copper alloy sheet
2: rolled surface
3: plane parallel to the rolled surface at a depth D less than the thickness t of the copper alloy sheet 1

Claims (7)

At least one kind selected from the group consisting of B, Mg, P, Cr, Mn, Fe, Co, Zn, Zr, Ag and Sn is contained in an amount of 1.0 to 6.0% by mass and 0.2 to 2.0% (B, Mg, P, Cr, Mn, Fe, Co, Zn, Zr, Ag, and Sn are contained in an amount of 0.000 to 2.000 mass%, and the balance of copper and inevitable impurities. Any one kind or more of them may be contained, and it is an optional addition component which does not need to contain any species)
The work hardening index (n _RD ) in the rolling parallel direction is 0.010 to 0.150,
The ratio n _RD / n _TD of the work hardening index n _{RD in the} rolling parallel direction to the work hardening index n _{TD in the} rolling direction is 0.500 to 1.500,
The depth of the copper alloy sheet material in the thickness direction from the surface of the rolled surface of the copper alloy sheet material is D and the depth of the copper alloy sheet material in the depth direction D parallel to the surface of the rolled surface The average value Sa of S (D) in the plate thickness direction is in the range of from 5.0 to 20% when the area ratio of the crystal grains having a stagger angle from the Cube orientation {001} < 100 & By weight, based on the total weight of the copper alloy sheet. The method according to claim 1,
Wherein the copper alloy sheet contains 0.005 to 2.000 mass% in total of at least one selected from the group consisting of B, Mg, P, Cr, Mn, Fe, Co, Zn, Zr, Ag and Sn. 3. The method according to claim 1 or 2,
Wherein the ratio a / b of the average grain size a in the rolling parallel direction to the average grain size b in the rolling direction is 0.8 or more with respect to the crystal grains of the base material. The method according to claim 1,
Wherein the flexural modulus in the rolling parallel direction and in the direction perpendicular to the rolling direction is not more than 140 GPa and the ratio E-RD of flexural modulus in the rolling parallel direction and flexural modulus E-TD in the perpendicular direction of rolling is 1.05 or less, Alloy sheet. A connector comprising the copper alloy sheet according to claim 1. A method for producing a copper alloy sheet material according to claim 1,
Each process of melting and casting process, ingot rolling process, homogenization heat treatment process, hot rolling process, quenching process, cold rolling 1 process, slit and trimming process, cold rolling 2 process, intermediate solution treatment process, quenching process, aging heat treatment process In this order,
In the ingot rolling process, the rolling process per pass is performed at least once at a machining rate of 1.0% or more,
In the cold rolling step, the average rolling pressure per pass is 50 N / mm &lt; ² &gt; or more so that the total machining ratio is 30% or more,
In the cold rolling step 2, the average rolling pressure per pass is 50 N / mm &lt; ² &gt; or more so that the total processing rate is 50%
Wherein the solution treatment is carried out in a high temperature region at a temperature rising rate of 5 占 폚 / sec or more and an arrival temperature of 600 to 1100 占 폚 in the intermediate solution treatment step. The method according to claim 6,
Wherein the acid cleaning and polishing step, the cold rolling step, and the final annealing step are performed in this order after the aging heat treatment step.

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