JP5224415B2 - Copper alloy material for electric and electronic parts and manufacturing method thereof - Google Patents

Description

  The present invention relates to parts for electrical and electronic equipment, such as connectors, terminal materials, etc., in particular, high-frequency relays and switches for which high conductivity is desired, connectors for automobiles, terminal materials, lead frames, etc. The present invention relates to a copper alloy material applied to electrical and electronic parts.

  Up to now, connectors (terminals, relays, switches, etc.) that are parts for electrical and electronic equipment include brass (C26000), phosphor bronze (C51910, C52120, C52100), beryllium copper (C17200, C17530) and corson copper alloys ( Hereinafter, it is also simply referred to as Corson copper, for example, a copper alloy such as C70250) has been used. Here, “Cxxxx” is a type of copper alloy defined by CDA (Copper Development Association).

  In recent years, currents used in electrical and electronic equipment have increased, and accordingly, high electrical conductivity has been required for copper alloy materials used in parts for electrical and electronic equipment. For example, brass or phosphor bronze has low conductivity, and Corson copper exhibits medium conductivity (conductivity of about 40% IACS) as a connector material, but higher conductivity is required. It is also well known that beryllium copper is expensive. On the other hand, pure copper (C11000), tin-containing copper (C14410), and the like, which have high conductivity, have a drawback of low strength. Therefore, there is a demand for a copper alloy having tensile strength and bending workability equivalent to those of electrical conductivity exceeding conventional Corson copper. Cu-Co (cobalt) -Si (silicon) -based alloys have attracted attention as copper alloys that satisfy this requirement. This Cu—Co—Si based alloy is a precipitation strengthening type copper alloy using an intermetallic compound of Co and Si.

  In particular, in recent electronic device parts, there are many connectors and terminals that have been subjected to complicated and severe bending as the device is downsized. This is because the size of the connector is downsized as the size is reduced, but in order to maintain the reliability of the contact, it is desired to have a contact length as long as possible. Connectors and terminals having such a design concept are often referred to as bellows (bellows) bending connectors or bellows bending terminals. In other words, there is a high demand for installing and installing terminals and connectors bent in a complicated manner in small parts. On the other hand, the material of the connector and terminal used with size reduction becomes thinner. This is also progressing from the viewpoint of weight reduction and resource saving. Thin materials are required to have higher strength than thick materials in order to maintain the same contact pressure.

  As a method for increasing the strength of the copper alloy material, there are various strengthening methods such as solid solution strengthening, work strengthening, and precipitation strengthening. In copper alloy materials, conductivity and strength are generally in a reciprocal relationship, but it is known that precipitation strengthening is promising as a method of increasing strength without reducing the conductivity of copper alloy materials. This precipitation strengthening is a high temperature heat treatment of an alloy added with an element that causes precipitation, so that these elements are dissolved in the copper matrix phase, and then heat treated at a temperature lower than the temperature at which the solid solution is formed. This is a technique for precipitating the deposited elements. For example, beryllium copper, corson copper, etc. employ the strengthening method.

  By the way, in the copper alloy material, in addition to the relationship between conductivity and strength, the relationship between bending workability and strength is also in an opposite relationship. In order to increase the strength, it is considered effective to increase the final cold rolling rate, but when the cold rolling rate is increased, the bending workability tends to be remarkably deteriorated. Until now, beryllium copper, corson copper, titanium copper and the like have been considered to have a good balance between bending workability and strength as precipitation-type copper alloys. However, for beryllium copper, beryllium, which is an additive element, is regarded as an environmentally hazardous substance, and an alternative material is required. Corson copper and titanium copper generally do not have a conductivity of 50% IACS or higher. Applications requiring high conductivity of 50% IACS or higher include, for example, battery terminals and relay contacts to which a high current is applied. In general, a material having high conductivity has excellent heat conduction characteristics, so that a material such as a CPU (integrated arithmetic element) socket or heat sink that requires heat dissipation also has high conductivity. Particularly in recent hybrid vehicles and CPUs that perform high-speed processing, materials having high conductivity and high strength are required.

  From such a background, a copper alloy using an intermetallic compound composed of Co and Si in consideration of strength, bending workability, and conductivity (thermal conductivity) has been attracting attention. A copper alloy that essentially contains Co and Si is known as follows.

Patent Document 1 discloses a copper alloy that essentially contains Zn (zinc), Mg (magnesium), and S (sulfur) in addition to Co and Si in order to improve hot workability.
Patent Document 2 discloses an alloy containing Mg, Zn, and Sn (tin) in addition to Co and Si.
Patent Document 3 discloses an alloy containing Sn and Zn in addition to Co and Si.
Patent Document 4 discloses a Cu—Co—Si alloy that is a precipitation-strengthened alloy for lead frames.
Patent Document 5 discloses a Cu—Co—Si based alloy in which the size of inclusions to be precipitated is 2 μm or less.
Patent Document 6 discloses a Cu—Co—Si based alloy in which a Co ₂ Si compound is precipitated.

JP-A-61-87838 JP-A 63-307232 Japanese Patent Laid-Open No. 02-129326 Japanese Patent Laid-Open No. 02-277735 JP 2008-88512 A JP 2008-55977 A

  However, the techniques disclosed in Patent Documents 1 to 6 have the following problems.

For example, these as either electrical and electronic parts applications, strength, electrical conductivity, and not aimed to simultaneously satisfy the bending workability, also does not address the details of the state of the alloy.
Further, none of the techniques described in each patent document satisfies the strength, bending workability, and conductivity (thermal conductivity) at a high level.
Unlike the present invention, the technique disclosed in Patent Document 1 is a copper alloy containing S as an essential constituent element, and its purpose is to improve hot workability unlike the present invention. Therefore, for example, Patent Document 1 does not describe the precipitates (particularly Co and Si precipitates), and it is unclear what the precipitates are, and the control method thereof is also unknown. Moreover, the result of having evaluated various characteristics, such as intensity | strength and electroconductivity calculated | required as an electric electronic component, is not described.
Although Patent Document 2 describes that a precipitate of Co and Si is a Co ₂ Si compound, details (particle size and the like) of the precipitate and a control method are unknown. In addition, as a manufacturing method, although there is a description that annealing was performed at a temperature of 500 ° C. for 1 hour or at a temperature of 450 ° C. for 1 hour, there is no description about recrystallization treatment, and even if this description is included, the base material The crystal grain size of is unknown. That is, it is thought that the copper alloy by the technique disclosed in Patent Document 2 has insufficient characteristics as a copper alloy for electrical and electronic parts that require high conductivity and high strength.
Patent Document 3 also describes that the precipitate of Co and Si is a Co ₂ Si compound, but details (particle size, etc.) and control method of the precipitate are unknown, and its conductivity is 30. % IACS or less and relatively low. In addition, as a manufacturing method, although there exists description that the solution treatment and cold rolling are performed at the temperature of 950 degreeC before annealing for 1 hour at the temperature of 400-500 degreeC, electrical conductivity is 30% IACS or less Therefore, it can be said that the properties are insufficient as a copper alloy for electrical and electronic parts requiring high conductivity and high strength.
Although the Cu-Co-Si alloy described in Patent Document 4 is used for lead frames and is described as a precipitation-strengthened alloy, the specific compound forming the precipitate and its details (particle size, etc.) are unknown. It is. In addition, as a manufacturing method, although there is description that heat treatment for 1 hour at a temperature of 500 ° C., followed by cold rolling and strain relief annealing for 1 hour at 300 ° C., there is no description about recrystallization treatment, Even if described, the crystal grain size of the base material is unknown. That is, it is thought that the copper alloy by the technique disclosed in Patent Document 4 has insufficient properties as a copper alloy for electrical and electronic parts that require high conductivity and high strength.
The Cu—Co—Si alloy described in Patent Document 5 has a description that the size of inclusions precipitated in the alloy is 2 μm or less, but details such as the definition of inclusions are unknown. Moreover, only the example manufactured through the process of rolling an ingot at room temperature as it is is shown. Here, considering that generally strict particle size control is required to obtain desired alloy characteristics, the copper alloy according to the technique disclosed in Patent Document 5 requires high conductivity and high strength. It is considered that the characteristics are insufficient as a copper alloy for electrical and electronic parts.
Patent Document 6 also describes that the precipitate of Co and Si is a Co ₂ Si compound, but details (particle size and the like), control method, and density of the precipitate are unknown. In addition, as a manufacturing method, although it describes that heat processing of 700-1050 degreeC is carried out before final rolling, it describes that the compound which precipitated at this temperature is a re-solid solution (solution treatment temperature), and is final. It is unclear whether or not Co and Si precipitates exist. As a result, it is considered that the characteristics are insufficient as a copper alloy for electrical and electronic parts requiring high conductivity and high strength.
Further, Patent Document 5 and Patent Document 6 have examples in which bending workability is evaluated under the condition of R / t = 1 at a specific strength level when the inner bending radius of the material is R and the thickness is t. However, at this level, it is considered that the bending workability required in the future may not always be supported.

As described above, the techniques disclosed in Patent Documents 1 to 6 have unclear points and contradictions, and it is possible to obtain a material having high conductivity and high strength only by the techniques disclosed in each of the above patent documents. in-out was bought Do not.

  In addition, in order to obtain sufficient alloy properties as a copper alloy for electrical and electronic parts requiring high conductivity and high strength, it is necessary to strictly control the crystal grain size of the base material and the grain size of the precipitate. However, this is not described in each patent document. That is, the copper alloy according to the invention disclosed in each patent document is considered to have insufficient characteristics as a copper alloy for electrical and electronic parts that require high electrical conductivity and high strength.

The present invention provides a copper alloy material in which the value of the crystal grain size of a Cu-Co-Si based copper alloy is controlled within a predetermined range in order to satisfy all of high conductivity, high strength, and good bending workability. it is a challenge to.

In order to obtain a copper alloy material particularly suitable for electrical and electronic component applications that require high electrical conductivity and high strength, the present inventors have further studied the relationship between electrical conductivity, strength, and bending workability in copper alloy materials. The present invention has been completed.

According to the present invention, the following means are provided:
(1) 0.7 to 2.0% by mass of Co (cobalt), 0.1 to 0.5% by mass of Si (silicon), respectively, and having a composition consisting of the balance Cu (copper) and inevitable impurities, A copper alloy material for electrical and electronic parts having a mass ratio of Co to Si (Co / Si) of 3 or more and 5 or less, wherein the arithmetic average of the crystal grain size of the base copper alloy is 3 to 20 μm, and the standard deviation is 8 μm. The standard deviation is smaller than the arithmetic mean, the particle diameter of the precipitate composed of Co and Si is 5 to 50 nm, and the density of the precipitate is 1 × 10 ⁸ to 1 × 10 ¹⁰ pieces / mm. ^{2. A} copper alloy material for electrical and electronic parts having a tensile strength of 570 MPa or more and a conductivity of 60% IACS or more as a copper alloy material.
(2) Further, in the item (1), at least one selected from the group consisting of Cr (chromium) and Ni (nickel ) is contained in a total amount of 0.01 to 1.0% by mass, and the balance is copper and inevitable impurities. The copper alloy material for electrical and electronic parts as described.
(3) In addition, T i a (titanium) containing 0.01 to 0.1 wt%, the balance being copper and inevitable impurities (1) or electrical and electronic components for the copper alloy material according to (2).
( 4 ) The copper alloy material for electrical and electronic parts according to any one of (1) to ( 3 ), wherein a value obtained by dividing the standard deviation by the arithmetic average is 0.65 or less.

( 5 ) A copper alloy material having the composition according to any one of (1) to ( 3 ) is melt-cast,
Hot rolled,
Chamfering,
Cold rolled,
Recrystallization heat treatment,
Each process has an aging heat treatment,
The melt casting step is a step of casting while cooling at a cooling rate of 10 to 30 K / second (where K is Kelvin indicating an absolute temperature) to obtain an ingot,
The hot rolling step is a step in which the ingot is processed after being held at a temperature of 900 to 1000 ° C. for 30 minutes to 60 minutes and rapidly quenched with water cooling, that is, rapid cooling.
The recrystallization heat treatment step is a step in which heat treatment is performed for a certain time in a salt bath maintained at a temperature of 800 to 1025 ° C., and then quenched rapidly with water cooling. Above 300 ° C., it is 10 to 300 K / second, and the cooling rate is 30 to 200 K / second,
The rate of temperature rise until reaching the maximum temperature from room temperature in the aging heat treatment step is in the range of 3 to 25 K / min, and when the temperature is lowered, the temperature is cooled to 300 ° C. in the range of 1 to 2 K / min. And
The arithmetic average of the crystal grain size of the copper alloy as a base material is 3 to 20 μm, the standard deviation is 8 μm or less, the standard deviation is smaller than the arithmetic average, and the particle diameter of the precipitate made of Co and Si is 5 An electrical / electronic component having a density of 1 × 10 ⁸ to 1 × 10 ¹⁰ pieces / mm ² at 50 nm, a tensile strength as a copper alloy material of 570 MPa or more, and a conductivity of 60% IACS or more. A method for producing a copper alloy material for electrical and electronic parts according to any one of (1) to ( 4 ), wherein the copper alloy material is obtained.
( 6 ) The holding temperature in the recrystallization heat treatment step is
When the addition amount of Co is less than 1% by mass, the holding temperature during the recrystallization heat treatment is 850 ° C. or more and less than 900 ° C.,
When the addition amount of Co is 1% by mass or more, the method for producing a copper alloy material for electrical and electronic parts according to ( 5 ), wherein the holding temperature during recrystallization heat treatment is 900 ° C. or more and less than 1000 ° C.

  Further, the “particle diameter (size) of the precipitate” is an average particle diameter of the precipitate obtained by the method described later, and the “crystal particle diameter” is based on JIS-H0501 (cutting method) described later. It is a measured value.

More this onset bright, intensity, conductivity, excellent in bending workability, it is possible to provide a suitable copper alloy material in electrical and electronic device applications.

These and other features and advantages of the present invention will become more apparent from below Symbol description.

A preferred embodiment of the copper alloy material of the present invention will be described in detail. Here, the “copper alloy material” means a copper alloy material (which means a mixture of each component element of a copper alloy having no concept of shape) having a predetermined shape (for example, plate, strip, foil, rod, It means the one after being processed into a line. Further, the “base copper alloy” means a copper alloy not including the concept of shape.
In addition, although a board | plate material and a strip are demonstrated as a preferable specific example of copper alloy material, the shape of a copper alloy material is not restricted to a board | plate material or a strip.

Next, a preferred embodiment of the present onset bright copper alloy material will be described in detail.

In the present invention, 0.7 to 2.0 mass% of Co (cobalt) is contained as an essential additive element, and the mass ratio of Co to Si (Co / Si) is 3 or more and 5 or less. It is a copper alloy material to be contained in the range (in the range of 0.1 to 0.5% by mass). As a result, the electrical conductivity is 60% IACS or higher and the tensile strength is 570 MPa or higher, and the requirement for high conductivity and high strength can be satisfied at a particularly high level. In the present invention, the electrical conductivity of the copper alloy material is 60% IACS or higher, and the higher the better, the upper limit is usually about 75% IACS. Further, tensile strength of the copper alloy material in the present invention, more preferably 600MPa or more, more preferably not more than 750 MPa, but preferably higher, the upper limit is usually about 900 MPa.

In addition, it is useful for further improving the bending workability that the arithmetic average of the crystal grain size of the base copper alloy is 3 to 20 μm and the standard deviation is 8 μm or less. The standard deviation is preferably as small as possible, the standard deviation of the grain size Ru arithmetic mean value less than Der grain size. When the arithmetic mean and standard deviation of the crystal grain size of the copper alloy as the base material are within the above ranges, the bending stress (strain applied) can be sufficiently dispersed. In order to further improve the bending workability, it is preferable that the value obtained by subtracting the standard deviation from the arithmetic average of the crystal grain size of the base copper alloy is larger than 0 μm, and the value obtained by dividing the standard deviation by the arithmetic average is It is more preferably 0.65 or less, and further preferably 0.4 or less. It is practical that the lower limit of the value obtained by dividing the standard deviation by the arithmetic average is 0.2 or more. When the value is smaller than this value, the characteristics are improved, but actual manufacturing tends to be difficult. Here, it is preferable to set the measurement parameter for obtaining the arithmetic mean and standard deviation of the crystal grain size of the copper alloy as a base material to 100 or more, and the measurement parameters for the arithmetic mean and standard deviation are the same value. It is more preferable.
In the copper alloy material of the present invention, the particle diameter (average particle diameter) of the precipitate composed of Co and Si is set to 5 to 50 nm. When the particle diameter of the precipitate is 5 nm or more, a sufficient precipitation strengthening amount can be obtained. Moreover, since this precipitate precipitates in alignment with the copper matrix and strengthens the material, the strength of the material is ensured when the particle diameter of the precipitate is 50 nm or less. Preferably the size of the precipitate is 10-30 nm, more preferably 20-30 nm.
Regarding the precipitation density, the distribution density of precipitates made of Co and Si is set to 1 × 10 ⁸ to 10 ¹⁰ pieces / mm ² .

  Regarding the bending workability, when the tensile strength is 570 MPa or more and 650 MPa or less, the value of R / t is 0.5 or less, and when the tensile strength is over 650 MPa and 700 MPa or less, the value of R / t is 1.0. Hereinafter, when the tensile strength exceeds 700 MPa, the value of R / t is preferably 1.5 or less. Here, R / t means the result of a W-bending test at a bending angle of 90 ° in accordance with the Japan Copper and Brass Association technical standard “Evaluation method for bending workability of copper and copper alloy sheet strip (JBMA T307)”. Then, a plate material cut in the vertical direction of rolling is subjected to a bending test under the condition of a predetermined bending radius (R), and the limit R at which the crack does not occur at the apex is obtained, and the thickness (t) at that time This is the value normalized by. In general, the smaller the R / t, the better the bending workability. In the copper alloy material for electric and electronic parts of the present invention, it is preferable that the tensile strength and the bending workability (R / t) have the above relationship. Further, the lower limit of the bending workability (R / t) is zero.

Hereinafter, additive elements other than Co and Si will be described.
Fe, Cr, and Ni are elements that contribute to strength improvement by forming a compound with Si by substitution with Co. Fe, Ni, and Cr are substituted for part of Co to form a (Co, χ) ₂ Si compound (χ is Fe, Ni, Cr), and has the function of improving strength. At least one of these elements (each element, a combination of any two kinds of elements may be any of the three kinds) may be in the range of 0.01 to 1.0 mass% in total. If it is 0.01% by mass or more, the effect is remarkably exhibited. If the total is 1.0% by mass or less, crystallization occurs during casting, or an intermetallic compound that does not contribute to strength is formed. There is no influence such as a decrease in conductivity. Even if these elements are added in combination or added alone, almost the same effect is seen, but when Ni is added, a remarkable strength improvement effect is exhibited. The addition amount of Fe, Ni, and Cr is preferably 0.05 to 0.9% by mass in total of at least one of these elements.
Zr and Ti also have almost the same effect as Fe, Ni and Cr, but Zr and Ti are easily oxidized, and if added in a large amount, cracking may occur in the material being produced. About the addition amount of Ti, it is preferable to make at least 1 sort (s) of these elements into the range of 0.01-0.1 mass% in total.

Sn, Zn, Mg, and Mn are characterized by solid solution in the copper matrix and strengthening. If the added amount is 0.01% by mass or more in total of at least one of these elements, the effect is obtained, and if it is 1.0% by mass or less, the conductivity is not hindered. A preferable addition amount is 0.05 to 0.2% by mass of at least one of these elements.
The unavoidable impurities in the onset bright copper alloy material, H, C, O, S, and the like.

  Zn has the effect of improving solder adhesion, and Mn has the effect of improving hot workability. Addition of Sn and Mg is effective in improving the stress relaxation resistance. Although the effect can be seen even when individual Sn and Mg are added, it is an element that exhibits the effect synergistically when added simultaneously. If the added amount is 0.1% by mass or more in total of at least one of these elements, the effect is obtained, and if it is 1.0% by mass or less, the conductivity is not impaired, and 50% IACS or more. Conductivity is ensured. On the other hand, with respect to the addition ratio of Sn and Mg, when Sn / Mg ≧ 1, the stress relaxation resistance is further improved.

Next, an example of a process for producing the present onset bright copper alloy material.
<Melting casting>
Copper, cobalt, silicon, etc., which are copper alloy raw materials, are melted and poured into a mold and cast while cooling at a cooling rate of 10 to 30 K / second (K is “Kelvin” indicating absolute temperature; the same applies hereinafter). To obtain a copper alloy ingot. Here, the width is 160 mm, the thickness is 30 mm, and the length is 180 mm.
<Hot rolling / facing / cold rolling>
Thereafter, this ingot is held at a temperature of 900 to 1000 ° C. for 30 to 60 minutes, and thereafter processed by hot rolling until the thickness becomes 12 mm, and then rapidly quenched with water cooling (rapid cooling), on the surface In order to remove the oxide film, the rolled surface is chamfered about 1 mm on one side to about 10 mm, and then processed to a thickness of about 0.1 to 0.3 mm by cold rolling.
<Recrystallization heat treatment>
Then, for the purpose of solution and recrystallization, recrystallization heat treatment is performed for a certain time (here, 30 seconds) in a salt bath (salt bath furnace) maintained at a temperature of 800 to 1025 ° C., and quenching is performed with water cooling. Do. During the recrystallization heat treatment, the temperature rise rate is adjusted by sandwiching the sample between stainless steel plates having different thicknesses. A preferable temperature increase rate at this time is 10 to 300 K / sec at a temperature of 300 ° C. or higher. Moreover, a preferable cooling rate is 30 to 200 K / sec.
<Aging heat treatment>
Next, an aging heat treatment is performed at a temperature of 525 ° C. for 120 minutes for the purpose of aging precipitation. In this case, the rate of temperature rise from room temperature to the maximum temperature is in the range of 3 to 25 K / min. When the temperature is lowered, the temperature is sufficiently lower than 300 ° C., which is sufficiently lower than the temperature range considered to affect precipitation. Performs cooling in the furnace within a range of 1 to 2 K / min.
<Finish rolling (if necessary)>
The final cold-rolled material is obtained by subjecting the copper alloy material after the aging heat treatment to a final cold rolling at a processing rate of 0% to 40% (the upper limit is preferably 20%). Note that finish rolling may or may not be performed. A processing rate of 0% means that finish rolling is not performed.
<Strain relief annealing>
After finishing the aging heat treatment (finished rolling is after finishing rolling), if necessary, strain relief annealing is performed.
<Repeating process>
The recrystallization heat treatment and the aging heat treatment may be repeated twice or more under the above conditions.

  Basically, the grain size and distribution (standard deviation) of crystal grains are determined by recrystallization heat treatment and aging heat treatment. In order to change the grain size and distribution of crystal grains, it is effective to control the rate of temperature rise, the holding temperature at the time of heat treatment, and the cooling rate in recrystallization heat treatment and aging heat treatment.

Further, heating rate, holding temperature during the heat treatment, the cooling rate, since also relates to the addition amount of an essential additive elements in the present onset bright copper alloy material Co, Si, Co, adjusting the addition amount of Si By doing so, the grain size and distribution of the crystal grains can be changed. Furthermore, by adding elements other than Cu, Co, and Si, precipitates other than crystal grains can be dispersed in the copper alloy, and the grain size and distribution thereof can be changed by the action.

The copper alloy material of the present invention is required to have an arithmetic average crystal grain size of 3 μm to 20 μm and a standard deviation of 8 μm or less in order to satisfy all of high conductivity, high strength, and good bending workability. . The standard deviation is preferably as small as possible, the standard deviation of the grain size Ru arithmetic mean value less than Der grain size. When the arithmetic mean and standard deviation of the crystal grain size of the copper alloy as the base material are within the above ranges, the bending stress (strain applied) can be sufficiently dispersed.
Therefore, the above-described additive elements and production conditions (particularly conditions for recrystallization heat treatment and aging heat treatment) are appropriately adjusted so as to satisfy the arithmetic average and standard deviation conditions of the crystal grain size. In particular, when the arithmetic average of the crystal grain size is less than 3 μm, an unrecrystallized region remains and directly leads to deterioration of the bending characteristics. Therefore, the standard deviation of the crystal grain size is smaller than the arithmetic average of the crystal grain size. preferably there, you as a 3μm or more.
In order to further improve the bending workability, the value obtained by subtracting the standard deviation from the arithmetic mean of the crystal grain size of the base copper alloy is preferably larger than 0 μm, and the standard deviation is divided by the arithmetic mean. The value is more preferably 0.65 or less, and further preferably 0.4 or less. It is practically practical that the lower limit of the value obtained by dividing the standard deviation by the arithmetic average is 0.2 or more.

Here, the temperature increase rate in the recrystallization heat treatment will be described.
If the rate of temperature rise is too slow, the heat treatment will be over, resulting in coarsening of precipitates and crystallized materials, and there is a risk that strength will be reduced. Moreover, there is a possibility that crystal grain coarsening occurs due to overheating. On the other hand, when the rate of temperature rise is too fast, the number of precipitates generated to prevent coarsening of the crystal grains decreases, and there is a risk that the crystal grains become coarse. For this reason, a preferable temperature increase rate becomes as above.

  It is also effective to adjust the recrystallization heat treatment temperature by the amount of Co added. When the addition amount of Co is less than 1% by mass, the holding temperature at the recrystallization heat treatment is set to 850 ° C. or more and less than 900 ° C., and when the addition amount of Co is 1% by mass or more, the holding temperature at the recrystallization heat treatment is set to It is preferable to set it to 900 degreeC or more and less than 1000 degreeC. If the holding temperature during the recrystallization heat treatment is lower than this range, there is a risk that the strength will be insufficient.If the holding temperature during the recrystallization heat treatment is higher than this range, the bending property may be deteriorated due to grain coarsening. This is because the copper alloy material may be deformed.

In addition, the following are mentioned as another preferable embodiment of this invention.
( C3) A copper alloy material in which Co is 0.7 to 2.5 mass% (the upper limit is preferably 2.0 mass%), and the mass ratio of Co to Si (Co / Si) is 3 or more and 5 or less. There,
A copper alloy material characterized in that an arithmetic average of crystal grain size of a copper alloy as a base material is 3 to 20 μm, a standard deviation is 8 μm or less, and the standard deviation is smaller than the arithmetic average.
The embodiments of the previous SL (C3), for example, the alloy composition, additive elements, states of grains and precipitate, a manufacturing method (manufacturing steps, and manufacturing conditions) for further and these embodiments the preferred range etc., are all similarly except for members that is different from the present onset bright. Further, embodiments of the (C3) is to the same effect as the present onset bright.

  EXAMPLES Next, although this invention is demonstrated further in detail based on an Example, this invention is not limited to them.

(Example 1 )
An alloy containing the components shown in Table 1 and the balance consisting of Cu and inevitable impurities is melted in a high-frequency melting furnace, which is cast at a cooling rate of 10 to 30 K / sec, 160 mm wide, 30 mm thick, and long. A 180 mm ingot was obtained. In addition, the cooling temperature was performed on the conditions which a crack etc. do not generate | occur | produce in an ingot.
The obtained ingot is held at a temperature of 1000 ° C. for 30 minutes, hot rolled to produce a hot-rolled sheet having a thickness t = 12 mm, both sides thereof are each 1 mm chamfered to a thickness t = 10 mm, The sheet thickness t was finished to 0.3 mm by cold rolling, and then recrystallization heat treatment was performed at a temperature in the range of 800 to 1025 ° C. The recrystallization heat treatment temperature was changed as shown in Table 1 according to the amount of Co added. And the following two processes were given with respect to the material after recrystallization heat processing, and the test material equivalent to a final product was created.
Step A: Recrystallization heat treatment-Aging heat treatment (temperature of 525 ° C for 2 hours)-Cold working (0 to 20%)
* After this, if necessary, strain relief annealing was performed at a temperature of 300 to 400 ° C. for 1 to 2 hours.
Step B: Recrystallization heat treatment-cold rolling (0 to 20%)-aging heat treatment (temperature of 525 ° C for 2 hours)

The following property investigation was conducted on this specimen. Table 1 shows the evaluation results of the characteristics of the copper alloy material as an alloy.
a. Tensile strength:
Three test pieces of JIS Z2201-13B cut out in the rolling parallel direction of the test material were measured according to JIS Z2241, and the average value was shown.
b. Conductivity measurement:
Using a four-terminal method, the conductivity was measured for two of each test piece in a thermostatic chamber controlled at 20 ° C. (± 1 ° C.), and the average value (% IACS) is shown in Table 1. At this time, the distance between terminals was set to 100 mm.
c. Bendability:
Specimens were cut out from the test material to a width of 10 mm and a length of 35 mm perpendicular to the rolling direction, and the bending axis was parallel to the rolling direction and the bending radius R = 0 to 0.5 (mm) at six levels of 90 °. W-bending (Bad-way bending) was performed, and the presence or absence of cracks in the bent portion was visually observed with a 50 × optical microscope, and the bending portion was observed with a scanning electron microscope (SEM) to investigate the presence or absence of cracks. In Table 1, R of R / t is a bending radius, t indicates a plate thickness, and a smaller value indicates better bending workability.
d3. Crystal grain size (arithmetic mean):
After the cross section perpendicular to the rolling direction of the test piece is polished to a mirror surface by wet polishing and buffing, the polished surface is corroded for several seconds with a solution of chromic acid: water = 1: 1, and then magnification is 200 to 400 times with an optical microscope. Alternatively, a photograph was taken at a magnification of 500 to 2000 using a secondary electron image of a scanning electron microscope (SEM), and the crystal grain size was measured according to the cutting method of JIS H0501. And the arithmetic mean was calculated | required by setting the measurement parameter to 200, and this value was made into the value of the arithmetic mean of a crystal grain diameter. In the table, “average grain size” is indicated.
e3. Crystal grain size deviation:
The grain size was measured one by one by the same method as the above grain size measurement, and the standard deviation of the grain size was determined with the measurement parameter being 200.
f. Precipitate size and density
The size of the precipitate was evaluated using a transmission electron microscope (TEM). In the final product, the structure of the material after aging heat treatment was observed because it was difficult to observe due to the influence of processing strain. Cut out a specimen for TEM from an arbitrary place on the heat treatment material, and perform electrolytic polishing (using a twin jet electrolytic polishing apparatus) in a temperature range of −20 to −25 ° C. using a methanol solution of nitric acid (20%). A test specimen for observation was completed.
Thereafter, observation was carried out at an acceleration voltage of 300 kV, and three 100000 times photographs were taken arbitrarily with the incident direction of the electron beam being set in the vicinity of (001). Using the photograph, the average size and number of precipitates (about 100) were obtained.

Table 1 as described in, in the example according to the present invention, are added strength, the conductive fill. Separately, when the bending workability was tested, good results were obtained in the examples according to the present invention, and the examples according to the present invention satisfied all of strength, conductivity, and bending workability in a well-balanced manner. Confirmed that. Specifically, the electrical conductivity is 60% IACS or more, the tensile strength is 570 MPa or more and 650 MPa or less, the R / t value is 0.5 or less, the tensile strength is over 650 MPa and 700 MPa or less, and the R / t is R / t. When the value was 1.0 or less and the tensile strength exceeded 700 MPa, the R / t value was 1.5 or less. On the other hand, in the example which did not follow this invention, the result which does not satisfy said value was brought.

  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 includes Japanese Patent Application No. 2008-197672 filed in Japan on July 31, 2008, Japanese Patent Application No. 2008-197677 filed in Japan on July 31, 2008, and August 5, 2008. Claiming priority based on Japanese Patent Application No. 2008-202468, filed in Japan, which is incorporated herein by reference in its entirety.

Claims (6)

Co (cobalt) 0.7-2.0 mass%, Si (silicon) 0.1-0.5 mass%, respectively, the composition consisting of the balance Cu (copper) and inevitable impurities, Co Co Si A copper alloy material for electrical and electronic parts having a mass ratio (Co / Si) of 3 to 5 and the arithmetic average of the crystal grain size of the base copper alloy is 3 to 20 μm, and the standard deviation is 8 μm or less. The standard deviation is smaller than the arithmetic mean, the particle diameter of the precipitate composed of Co and Si is 5 to 50 nm, and the density of the precipitate is 1 × 10 ⁸ to 1 × 10 ¹⁰ pieces / mm ² . And the copper alloy material for electrical and electronic components whose tensile strength as a copper alloy material is 570 Mpa or more and whose electrical conductivity is 60% IACS or more. The electrical / electronic component according to claim 1, further comprising 0.01 to 1.0% by mass in total of at least one selected from the group consisting of Cr (chromium) and Ni (nickel ), with the balance being copper and inevitable impurities. Copper alloy material. Furthermore, T i (titanium) and containing 0.01 to 0.1 wt%, electrical and electronic components for the copper alloy material according to claim 1 or claim 2 the remainder being copper and inevitable impurities. The copper alloy material for electrical and electronic parts according to any one of claims 1 to 3 , wherein a value obtained by dividing the standard deviation by the arithmetic average is 0.65 or less. Was dissolved cast copper alloy material having a composition according to any one of claims 1 to 3,
Hot rolled,
Chamfering,
Cold rolled,
Recrystallization heat treatment,
Each process has an aging heat treatment,
The melt casting step is a step of casting while cooling at a cooling rate of 10 to 30 K / second (where K is Kelvin indicating an absolute temperature) to obtain an ingot,
The hot rolling step is a step in which the ingot is processed after being held at a temperature of 900 to 1000 ° C. for 30 minutes to 60 minutes and rapidly quenched with water cooling,
The recrystallization heat treatment step is a step in which heat treatment is performed for a certain time in a salt bath maintained at a temperature of 800 to 1025 ° C., and then quenched rapidly with water cooling. Above 300 ° C., it is 10 to 300 K / second, and the cooling rate is 30 to 200 K / second,
The rate of temperature rise until reaching the maximum temperature from room temperature in the aging heat treatment step is in the range of 3 to 25 K / min, and when the temperature is lowered, the temperature is cooled to 300 ° C. in the range of 1 to 2 K / min. And
The arithmetic average of the crystal grain size of the copper alloy as a base material is 3 to 20 μm, the standard deviation is 8 μm or less, the standard deviation is smaller than the arithmetic average, and the particle diameter of the precipitate made of Co and Si is 5 An electrical / electronic component having a density of 1 × 10 ⁸ to 1 × 10 ¹⁰ pieces / mm ² at 50 nm, a tensile strength as a copper alloy material of 570 MPa or more, and a conductivity of 60% IACS or more. The method for producing a copper alloy material for electric and electronic parts according to any one of claims 1 to 4 , wherein the copper alloy material is obtained. Holding temperature in the recrystallization heat treatment step,
When the addition amount of Co is less than 1% by mass, the holding temperature during the recrystallization heat treatment is 850 ° C. or more and less than 900 ° C.,
The method for producing a copper alloy material for electrical and electronic parts according to claim 5 , wherein when the amount of Co added is 1% by mass or more, the holding temperature during recrystallization heat treatment is 900 ° C or higher and lower than 1000 ° C.