JP4785092B2 - Copper alloy sheet - Google Patents

Description

  The present invention relates to a copper alloy sheet.

  Examples of the characteristic items required for the copper alloy sheet used for electric / electronic equipment include, for example, constant conductivity, tensile strength, bending workability, stress relaxation resistance, and the like. In recent years, the level of these required characteristics has increased as electric and electronic devices have become smaller, lighter, more functional, higher-density mounted, and used in higher temperatures.

Conventionally, as materials for electric and electronic devices, copper-based materials such as phosphor bronze, red brass, brass and the like are widely used in addition to iron-based materials. These alloys have improved strength by a combination of solid solution strengthening of Sn and Zn and work hardening by cold working such as rolling and wire drawing. The alloy obtained by this strengthening method has insufficient electrical conductivity with respect to the recent required level, and has obtained high strength by adding a high cold work rate. The stress relaxation resistance is insufficient.
An alternative strengthening method is precipitation strengthening, in which a fine second phase (particles) of nanometer order is precipitated in the material. This strengthening method has a merit of improving the conductivity at the same time in addition to increasing the strength, and is therefore performed in many alloy systems. Among them, a Cu—Ni—Si alloy strengthened by finely depositing a compound of Ni and Si in Cu (for example, CDA 70250 which is a CDA [Copper Development Association] registered alloy: see Patent Documents 1 and 2) The amount used in that market is increasing.

JP 11-43731 A JP 2005-532477 A

In general, in a precipitation hardening type alloy, a solution heat treatment for dissolving solute atoms is introduced in an intermediate step before an aging precipitation heat treatment for obtaining a fine precipitation state. Although this temperature varies depending on the alloy system and solute concentration, it is as high as about 750 ° C., for example. Since the solution treatment temperature is high, there is a problem that the crystal grain size of the material becomes coarse. If the crystal grain size is coarse, the problem of cracking by promoting local deformation during bending, and the wrinkle on the surface of the bent part will increase, so when using the bent part as a contact point, Problems such as cracking of the plating applied to the material surface occur. In addition, if the temperature of the solution heat treatment is lowered in order to prevent the crystal grain size from becoming coarse, the amount of solid solution atoms decreases, and the density of fine precipitates in the aging treatment decreases, and age hardening occurs. The amount is reduced, causing a problem that the material strength is reduced.
Thus, there is a demand for a technique for controlling the crystal grain size to be small under a high temperature solution heat treatment that can sufficiently dissolve Ni and Si as solute atoms and obtaining a material having high strength and high bending workability.

  In view of the problems as described above, an object of the present invention is to provide a copper alloy sheet for electrical and electronic equipment materials having excellent bending workability and excellent strength.

  The present inventors have studied a copper alloy suitable for electric / electronic component applications, and in the Cu—Ni—Si based copper alloy, the second phase particles are dispersed in order to greatly improve the bending workability and strength. Focusing on the method, the present invention was reached after intensive studies. Further, in the present alloy system, an additive element having a function of improving the strength and the stress relaxation resistance characteristic is found without impairing the conductivity, and the preferred embodiment of the present invention has been achieved. Here, the second phase particles indicate a precipitate and a crystallized product.

According to the present invention, the following means are provided:
(1) A copper alloy sheet containing 1.8 to 3.3 mass% of Ni, 0.4 to 1.1 mass% of Si, 0.01 to 0.5 mass% of Cr, and the balance of Cu and inevitable impurities. When the tensile strength is 730 to 820 MPa, the material plate width is W (unit: mm), and the material plate thickness is T (unit: mm), the product of W and T (unit: mm ² ) Can be processed without cracks in 180 ° contact bending under the condition of 0.16 or less,
Furthermore, the second phase particles present on the crystal grain boundaries are present at a density of 10 ⁴ to 10 ⁸ particles / mm ² , and the average crystal grain size of the crystal grains is 10 μm or less. Copper alloy sheet.
(2) A Cu alloy plate material containing 1.8 to 3.3 mass% of Ni, 0.4 to 1.1 mass% of Si, 0.01 to 0.5 mass% of Cr, and the balance of Cu and inevitable impurities. When the tensile strength is 730 to 820 MPa, the material plate width is W (unit: mm), and the material plate thickness is T (unit: mm), the product of W and T (unit: mm ² ) Can be processed without cracks in 180 ° contact bending under the condition of 0.16 or less,
Furthermore, the value of r / f, which is the ratio of the particle diameter r (unit: μm) of all second phase particles including the inside of the crystal grains and the crystal grain boundaries, to the volume fraction f of the particles is 1-100. There, the copper alloy sheet average crystal grain size you wherein a is 10μm or less.
(3) The copper alloy sheet material according to (1) or (2), wherein the proportion of particles containing Cr as a constituent element in the second phase particles is 50% or more.
(4) The copper alloy sheet according to any one of (1) to (3), wherein the stress relaxation rate when held at 165 ° C. for 3000 hours is 30% or less.
(5) A total of at least one of Sn, Mg, Ag, Mn, Ti, Fe, and P is 0.01 to 1 mass%, Zn is 0.01 to 1.0 mass%, and Co is 0.01 to 1.%. The copper alloy sheet according to any one of (1) to (4), wherein one or more elements are included from 5 mass%.

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

1A and 1B are explanatory diagrams of a stress relaxation resistance test method. FIG. 1A shows a state before heat treatment, and FIG. 1B shows a state after heat treatment. FIG. 2 is a graph showing the results regarding the presence or absence of cracking when the plate width W (mm) and the plate thickness T (mm) of the test pieces in each of the examples and comparative examples are changed.

  A preferred embodiment of the copper alloy sheet material of the present invention will be described in detail.

The tensile strength of the copper alloy sheet of the present invention is 730 to 820 MPa. Preferably, it is 740-800 MPa.
The bending workability is that 180 ° contact bending is possible under severe conditions such that the product of the material plate width W (mm) and the material plate thickness T (mm) is 0.16 (mm ² ) or less. The product of W and T is preferably 0.14 or less. The lower limit of the product of W and T is not particularly limited, but is usually 0.01 or more.
The electrical conductivity is preferably 30% IACS or more, and the stress relaxation resistance is preferably 30% or less when held at 165 ° C. for 3000 hours or more.
It is effective to disperse the second phase appropriately for the coarsening of the crystal grains during solution treatment, which deteriorates the bending workability. This is considered to be because energy gain is generated at the interface between the dispersed particles and the crystal grain boundary when the crystal grain boundary passes through the second phase particle during grain growth of the crystal grain, and the grain boundary movement is suppressed.
The crystal grain size obtained is 10 μm or less , preferably 8 μm or less, more preferably 6 μm or less. Although there is no restriction | limiting in particular in the lower limit of a crystal grain diameter, Usually, it is 2 micrometers or more. The crystal grain size was measured based on JIS H 0501 (cutting method).

In order to sufficiently exhibit the effect of obtaining the controlled crystal grain size, the preferable dispersion state in the present invention is defined by the following two methods .
The first is that the second phase particles present on the grain boundaries are present at a density of 10 ⁴ to 10 ⁸ particles / mm ² . In this case, it is more preferably 5 × 10 ^{5 to} 5 × 10 ⁷ pieces / mm ² .
Second, the ratio of the particle diameter r (unit: μm) of all second phase particles including the inside of the crystal grains and the crystal grain boundaries to the volume fraction f of the particles, and the value of r / f is 1-100. Ru der that there. The particle diameter r of the second phase particles was the arithmetic average value of the measured particle diameters of all particles. In addition, the display of the volume fraction f is that f = 0.005 represents 0.5 vol%.

The present inventors have found that such second phase particles have a preferable function of improving stress relaxation resistance. The stress relaxation phenomenon is considered that the strain within the elastic limit is changed to a permanent strain because the dislocation within the crystal grain moves to the grain boundary or the grain boundary slips at a part of the grain boundary. In the preferred second phase particles in the present invention, it is considered that particles existing in the grains have a function of suppressing dislocation movement, and particles existing in the grain boundaries have a function of suppressing the sliding motion of the grain boundaries.
Of all the second phase particles, the proportion of particles containing Cr as a constituent element is more preferably 50% or more. This is because when Cr is contained, it can exist as a stable compound that does not dissolve in Cu even at higher temperatures. This contributes to the densification of the second phase particles and enhances the effect of suppressing the growth of crystal grains. This ratio is more preferably 70% or more. The upper limit of this ratio is not particularly limited, but is usually 90% or less.

  About Ni and Si which are main solute components, a favorable characteristic is acquired by controlling a compounding quantity as follows. The Ni content is preferably 1.8 to 3.3 mass%, more preferably 2.0 to 3.0 mass%, and the Si content is preferably 0.4 to 1.1 mass%, more preferably 0.5. -1.0 mass%. If these elements are added in an excessive amount, the electrical conductivity is lowered, and grain boundary cracking during bending is caused by precipitation at the grain boundaries. Moreover, when there is too little content of these elements, intensity | strength will run short.

  Cr precipitates as second phase particles with Ni and Si and is effective in controlling the crystal grain size. In addition, there is an effect of precipitation hardening as a Cr simple substance. The content is preferably 0.01 to 0.5 mass%, more preferably 0.03 to 0.4 mass%. If the amount is too small, the effect cannot be obtained. If the amount is too large, the crystallizes as a coarse crystallized product at the time of solidification, which deteriorates the plating property and promotes the base point of cracks and the propagation of cracks during plastic processing.

In addition, (1) at least one of Sn, Mg, Ag, Mn, Ti, Fe, and P in total is 0.01 to 1 mass%, (2) 0.01 to 10 mass% of Zn, and (3) Co is 0 At least one element selected from 0.01 to 1.5 mass% may be added to improve the alloy characteristics.
These elements improve strength and stress relaxation resistance, and are particularly effective for Sn and Mg. Zn and Sn function to improve solder bonding, Co to improve conductivity, and Mn to improve hot workability. When the content is too small, the effect is insufficient, and when it is too large, the conductivity is lowered.

  As for the stress relaxation resistance, it is preferable that the stress relaxation rate when held at 165 ° C. for 3000 hours is 30% or less. More preferably, it is 25% or less.

Below, the preferable manufacturing method of the copper alloy board | plate material of this invention is demonstrated. The copper alloy sheet material of the present invention is, for example, casting-(homogenization) heat treatment-hot working (for example, hot rolling)-cold working (for example, cold rolling) (1)-solution heat treatment-cold working. (For example, cold rolling) (2)-(aging precipitation) heat treatment-cold working (for example, cold rolling) (3)-(strain relief) It can manufacture by the method which consists of each process of annealing. Here, it is preferable to perform rapid cooling-facing after hot working and before cold working (1). Next, preferable conditions for each step will be described.
First, the respective elements are blended so as to have the predetermined alloy component composition, and a copper alloy material consisting of Cu and inevitable impurities is prepared, and this is melted by, for example, a high-frequency melting furnace. Casting is preferably performed at a cooling rate of 0.1 to 100 ° C./second (more preferably 0.5 to 50 ° C./second) to obtain an ingot. The (homogenization) heat treatment is performed by holding the ingot at 900 to 1050 ° C. for 0.5 to 10 hours (more preferably 0.8 to 8 hours). In the hot working (hot rolling), preferably, the cross-section reduction rate (rolling rate) is 50% or more (more preferably 60 to 98%) and the processing temperature is 600 ° C. or more (more preferably 620 to 1000 ° C.). To make a plate. Rapid cooling (for example, water cooling) is performed by cooling the plate at a cooling rate of preferably 10 ° C./second or more (more preferably 15 to 300 ° C./second). This hot rolled plate may be chamfered by a conventional method. Cold working (cold rolling) (1) is preferably performed with a cross-sectional reduction rate of 90% or more (more preferably 92 to 99%). The solution heat treatment is preferably performed by holding at 720 to 860 ° C. for 3 seconds to 2 hours (more preferably 5 seconds to 0.5 hours). In the solution heat treatment, the heating rate at 400 ° C. to 700 ° C. during the heating is preferably in the range of 0.1 ° C./second to 200 ° C./second (more preferably 0.5 to 100 ° C./second). It is preferable. Cold working (cold rolling) (2) is preferably performed at a cross-sectional reduction rate of 5 to 50% (more preferably 7 to 45%). The aging precipitation heat treatment is preferably performed by holding at 400 ° C. to 540 ° C. for 5 minutes to 10 hours (more preferably at 410 to 520 ° C. for 10 minutes to 8 hours). The cold working (cold rolling) (3) is preferably performed with a cross-sectional reduction rate of 10% or less (meaning more than 0% and 10% or less). The strain relief annealing is preferably performed by holding at 200 ° C. to 600 ° C. for 15 seconds to 10 hours (more preferably at 250 to 570 ° C. for 20 seconds to 8 hours).
If the strength is sufficient at the time of aging precipitation heat treatment, the subsequent cold working (3) and strain relief annealing can be omitted without performing.

  By performing at least one of the above steps under the above preferable conditions, and particularly preferably by performing all of the steps under the above preferable conditions, a predetermined preferable metallographic state is obtained in the copper alloy sheet of the present invention. be able to. For example, excessive crystallization of Cr-based compounds can be prevented by adjusting the casting speed (cooling speed during casting). Further, for example, by adjusting the temperature range of hot rolling and the time for maintaining the temperature, coarse precipitation during hot rolling can be suppressed, and sufficient precipitation can be performed in a later step. In addition, for example, the second phase particles that suppress the coarsening of crystal grains are precipitated mainly during the temperature rise of the solution heat treatment, but in order to cause the precipitation effectively, the cold working which is the pre-processing is performed. It is preferable that the processing rate of (1) and the temperature increase rate of the solution heat treatment be performed within the above-mentioned preferable conditions. Also, for example, by introducing cold working (2) before the aging precipitation heat treatment, it promotes the densification of fine precipitates that contribute to precipitation hardening, and remains during solution treatment during the aging precipitation heat treatment. It is possible to suppress the coarsening of the second phase particles.

The copper alloy sheet of the present invention is excellent in strength and bending workability, and is suitable for electric / electronic equipment applications. The preferable copper alloy sheet of the present invention is further excellent in conductivity and stress relaxation resistance. The copper alloy sheet material of the present invention is particularly suitable for lead frames, connectors, terminal materials, etc. for electrical and electronic devices, especially connectors and terminal materials for automobiles, relays, switches, sockets, etc., due to the characteristics as described above. Can be used.
There has never been a material with high strength and high bending workability like the present invention, and it will improve the degree of freedom of component design for the most advanced applications in the future, and it will be great for enhancing the functionality of electronic devices. Has an effect. In addition, it is possible to reduce the thickness of copper alloy materials by increasing the strength and contribute to the reduction of the amount of earth resources used.

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

Example 1
The elements are blended so as to be the components shown in the table, and the remainder consisting of an alloy consisting of Cu and inevitable impurities is melted in a high-frequency melting furnace, and this is cast at a cooling rate of 0.1 to 100 ° C./second to make an ingot Got. After maintaining this at 900 to 1050 ° C. for 0.5 to 10 hours, a plate is produced by hot working with a cross-section reduction rate of 50% or more and a processing temperature of 600 ° C. or more, and at a cooling rate of 10 ° C./second or more. Water cooling was performed. This hot-rolled sheet was chamfered, and cold working (1) with a cross-section reduction rate of 90% or more was performed. Thereafter, solution heat treatment was performed at 720 to 860 ° C. for 3 seconds to 2 hours. In the solution heat treatment, the heating rate at 400 ° C. to 700 ° C. during the heating was performed in the range of 0.1 ° C./second to 200 ° C./second. Thereafter, cold working (2) with a cross-sectional reduction rate of 5 to 50%, aging precipitation heat treatment for holding at 400 ° C. to 540 ° C. for 5 minutes to 10 hours, cold working with a cross-sectional reduction rate of 10% or less ( 3) Strain-relief annealing was performed at 200 ° C. to 600 ° C. for 15 seconds to 10 hours to obtain test materials. When the strength was sufficient at the time of aging precipitation heat treatment, the subsequent cold working (3) and strain relief annealing were not performed.

The comparative example written together with the following example is manufactured outside the range of these manufacturing conditions, and is out of the range of the example of the present invention.
The details are as follows:
Comparative Example 1-1 is an example in which the cooling rate in the casting process was too low.
Comparative Example 1-2 is an example in which the temperature of the homogenization step is too low.
Comparative Example 1-3 is an example in which the temperature of the aging precipitation heat treatment step is too high.
Comparative Example 1-4 is an example in which the temperature of the homogenization step is too low.
In each table, for example, the test result as Example 1-1 of the present invention as the identification number in Table 1 is outside the scope of the present invention where W × T> 0.16 in terms of evaluation of bending workability. The determination result of the bending condition is also shown in the same line as the determination result of the bending condition within the scope of the present invention, but this is for convenience of description of the identification number. Hereinafter, the same applies to the description of each test example in each table.

The following characteristics were investigated for these test materials.
a. Conductivity [EC]:
The specific resistance was measured by a four-terminal method in a constant temperature bath maintained at 20 ° C. (± 0.5 ° C.) to calculate conductivity (% IACS). In addition, the distance between terminals was 100 mm.
b. Tensile strength [TS]:
Three test pieces of JIS Z2201-13B cut out from the rolling parallel direction were measured according to JIS Z2241, and the average value (MPa) was shown.
c. 180 ° adhesion bending workability:
Bending was performed according to JIS Z 2248. Preliminary bending was performed using a 0.4 mm R 90 ° bending mold, and then contact bending was performed using a compression tester. The presence or absence of cracks on the outside of the bent part was observed by visual observation with a 50 × optical microscope, and the presence or absence of cracks was investigated. The test piece conditions are as follows: W is the plate width and T is the plate thickness in mm. In the table, “GW (Good way)” means that the bending axis is a test perpendicular to the rolling direction, and “BW (Bad way)” means that the bending axis is parallel to the rolling direction. It means that it is a test of each. In the table, the observation results are expressed as “◯ (good)” when no crack is generated and “× (defective)” when the crack is generated.
d. Particle size [r], distribution density [ρ] and volume fraction [f] of the second phase particles:
The specimen was punched into a diameter of 3 mm, and thin film polishing was performed using a twin jet polishing method to produce an observation test piece. Photographs with a viewing electron microscope with an acceleration voltage of 300 kV are arbitrarily photographed at a magnification of 10 for each 10 fields, and the particle diameter r (μm) and distribution density ρ (particles / mm ² ) of the second phase particles are measured on the photographs. did. The particle diameter r of the second phase particles was obtained by first obtaining the particle diameter of each particle for each particle and then taking the arithmetic average value of the particle diameter of each particle for all the measured particles. In addition, the particle diameter of each particle | grain was taken as the arithmetic mean value of the major axis and the minor axis of the particle. In addition, the thickness of the observation test piece was measured from the equal thickness interference fringes, and the ratio of the volume of the second phase particles in the total volume in the observation field was defined as the volume fraction f.
e. Identification of constituent atoms of the second phase [C]
An EDX analyzer attached to TEM was used. Twenty second phases were analyzed, and the ratio of those containing Cr to the total number measured was calculated.
f. Stress relaxation resistance [SR]:
The measurement was performed under the conditions of 165 ° C. × 3000 h in accordance with Japan Electronic Material Industries Association Standard EMAS-3003. An initial stress of 80% of the proof stress was applied by the cantilever method.
FIG. 1 is an explanatory diagram of a stress relaxation characteristic test method, in which (a) shows a state before heat treatment and (b) shows a state after heat treatment. The stress relaxation rate (%) was calculated as (H _t −H ₁ ) / δ ₀ × 100.
g. Average crystal grain size [GS]:
Measured based on JIS H 0501 (cutting method). Measurements were taken on a cross section parallel to the rolling direction and a cross section perpendicular to the rolling direction, and the average of the two was taken. The metal structure was observed by chemically edging the mirror-polished material surface and taking a reflection electron image of the SEM.

Table 1 As is apparent, the present invention embodiment 1-1～1- 4 has strength, electrical conductivity, bending workability, excellent characteristics as stress relaxation resistance. However, if any of the requirements of the present invention is not satisfied, any of the characteristics may be inferior. For example, Comparative Examples 1-1 to 1-4 are examples in which bending workability is inferior. In Comparative Examples 1-1, 1-2, and 1-4, the density of precipitates on the grain boundaries was low, and the crystal grain size was coarsened. In Comparative Example 1-3, the density of precipitates on the grain boundaries was high, and it was observed that cracks occurred at the crystal grain boundaries.

(Example 2)
The same investigation as in Example 1 was performed on a copper alloy having the composition shown in Table 2 with the balance being Cu and inevitable impurities. The manufacturing method and the measuring method were the same as in Example 1.
In addition, the comparative example written together with the following Example was manufactured out of the range of these manufacturing conditions, and was made to remove | deviate from the range of the Example of this invention. The details are as follows:
Comparative Example 2-1 is an example in which the processing rate in the cold working (cold rolling) process was too low.
Comparative Example 2-2 is an example in which the temperature of the homogenization step is too low.
Comparative Example 2-3 is an example in which the cooling rate in the casting process was too low.
Comparative Example 2-4 is an example in which the temperature of the homogenization step is too low.

Table 2 As is apparent, the present invention embodiment 2-1～2- 4 has strength, electrical conductivity, bending workability, excellent characteristics as stress relaxation resistance. However, if any of the requirements of the present invention is not satisfied, any of the characteristics may be inferior. For example, Comparative Example 2-1 is an example in which the tensile strength is inferior. In Comparative Example 2-1, the solution temperature was lowered to reduce the crystal grain size, but it is considered that the precipitation hardening was insufficient and the strength was insufficient. Comparative Examples 2-2 and 2-4 are examples inferior in bending workability. In Comparative Examples 2-2 and 2-4, it can be seen that the value of r / f was large because the precipitation fraction was small, and the crystal grain size was coarsened. Comparative Example 2-3 is an example inferior in bending workability. In Comparative Example 2-3, since the second phase particle diameter is small, the value of r / f is small, and it can be seen that the crystal grain size is coarsened without effective control of the crystal grains.

(Example 3)
The same investigation as in Example 1 was performed on a copper alloy having the composition shown in Table 3 with the balance being Cu and inevitable impurities. The manufacturing method and the measuring method were the same as in Example 1.
In Table 3, the comparative examples written together with the following examples are those in which the contents of Ni and Si deviate from the preferred range of the present invention.

  As is apparent from Table 3, the inventive examples 3-1 to 3-4, in which the contents of Ni and Si are in a particularly preferable range, are excellent in strength, conductivity, bending workability, and stress relaxation resistance. Have However, when the addition amounts of Ni and Si are not particularly within the preferable range, any of the characteristics may be inferior. For example, Comparative Example 3-1 shows an example in which the strength is insufficient because the amounts of Ni and Si are insufficient. Comparative Example 3-2 shows an example in which the amount of Ni and Si is large, so that precipitation at grain boundaries occurs and bending workability is slightly deteriorated. Of course, the contents of Ni and Si do not need to be in a particularly preferable range, but examples in which the characteristics are inferior by being out of this range can be seen. Therefore, as much as possible, Ni is 1.8 to 3.3 mass%, It can be said that Si is preferably in the range of 0.4 to 1.1 mass%.

Example 4
The same investigation as in Example 1 was performed on a copper alloy having the composition shown in Table 4 with the balance being Cu and inevitable impurities. The manufacturing method and the measuring method were the same as in Example 1.
In Table 4, the comparative examples written together with the following examples are those in which the content of other additive elements is out of the preferred range of the present invention.

  As is apparent from Table 4, Examples 4-1 to 4-4 of the present invention in which the content of other additive elements (also referred to as secondary additive elements) other than Ni and Si are particularly preferable are strength and conductivity. In addition, it has excellent properties in bending workability and stress relaxation resistance. However, if the content of other additive elements is not within the particularly preferred range, any of the characteristics may be inferior. For example, Comparative Example 4-1 shows an example in which bending workability is inferior. In Comparative Example 4-1, it was considered that the grain boundary became brittle because the amount of the auxiliary additive element was too large. Comparative Example 4-2 shows an example in which the mechanical strength is inferior. In Comparative Example 4-2, it is considered that a large amount of a compound other than the Ni—Si compound that contributes to precipitation hardening was formed because the addition amount of the secondary additive element was too large. Of course, the content of other additive elements does not need to be in a particularly preferable range, but there are cases where the characteristics are inferior due to being outside this range. As long as at least one of Sn, Mg, Ag, Mn, Ti, Fe, and P is added in total from 0.01 to 1 mass%, Zn from 0.01 to 10 mass%, and Co from 0.01 to 1.5 mass% It can be said that it is preferable to include one or more elements.

  The results of the above Examples 1 to 4 are shown in FIG. In the example of the present invention, the product of the specimen thickness T and the specimen width W of the material dimensions in 180 ° close contact bending was able to be processed without cracks on the condition that the product was 0.16 or less, whereas the comparative example could be processed. You can see that there wasn't.

  The copper alloy plate material of the present invention is suitably applied to lead frames, connectors, terminal materials, etc. for electrical and electronic equipment, such as connectors and terminal materials for automobiles, relays, switches, sockets, etc. .

  While this invention has been described in conjunction with its embodiments, we do not intend to limit our invention in any detail of the description unless otherwise specified and are contrary to the spirit and scope of the invention as set forth in the appended claims. I think it should be interpreted widely.

  This application claims priority based on Japanese Patent Application No. 2007-287066 filed in Japan on November 5, 2007, which is incorporated herein by reference. Capture as part.

Claims (5)

A copper alloy plate material containing 1.8 to 3.3 mass% of Ni, 0.4 to 1.1 mass% of Si, 0.01 to 0.5 mass% of Cr, and the balance of Cu and inevitable impurities, When the tensile strength is 730 to 820 MPa, the material plate width is W (unit: mm), and the material plate thickness is T (unit: mm), the product of W and T (unit: mm ² ) is 0.00. It is possible to process without cracks in 180 ° contact bending under the condition of 16 or less,
Furthermore, the second phase particles present on the crystal grain boundaries are present at a density of 10 ⁴ to 10 ⁸ particles / mm ² , and the average crystal grain size of the crystal grains is 10 μm or less. Copper alloy sheet. A Cu alloy plate material containing 1.8 to 3.3 mass% of Ni, 0.4 to 1.1 mass% of Si, 0.01 to 0.5 mass% of Cr, and the balance of Cu and inevitable impurities, When the tensile strength is 730 to 820 MPa, the material plate width is W (unit: mm), and the material plate thickness is T (unit: mm), the product of W and T (unit: mm ² ) is 0.00. It is possible to process without cracks in 180 ° contact bending under the condition of 16 or less,
Furthermore, the value of r / f, which is the ratio of the particle diameter r (unit: μm) of all second phase particles including the inside of the crystal grains and the crystal grain boundaries, to the volume fraction f of the particles is 1-100. There, the copper alloy sheet average crystal grain size you wherein a is 10μm or less.   3. The copper alloy sheet according to claim 1, wherein a ratio of particles containing Cr as a constituent element in the second phase particles is 50% or more. 4.   The copper alloy sheet according to any one of claims 1 to 3, wherein a stress relaxation rate when held at 165 ° C for 3000 hours is 30% or less. At least one of Sn, Mg, Ag, Mn, Ti, Fe, and P is 0.01 to 1 mass% in total, Zn is 0.01 to 1.0 mass%, and Co is 0.01 to 1.5 mass%. The copper alloy sheet according to any one of claims 1 to 4, wherein one or more elements are contained from the inside.

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