JP2007119844A - High strength copper alloy material having excellent bending workability and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copper alloy material combining high mechanical strength and satisfactory electric conductivity, and also having excellent bending workability. <P>SOLUTION: A copper alloy material comprising, by mass, 1.0 to 5.0% Ni and 0.2 to 1.0% Si, and the balance Cu with inevitable impurities, and in which, regarding the distribution of Ni<SB>2</SB>Si precipitates with a grain size of 0.03 to 3 μm observed in the cross-section vertical to the rolling direction, the ratio between the number density ((a) piece/mm<SP>2</SP>) in the surface layer and the number density ((b) piece/mm<SP>2</SP>) in the internal layer is ≤0.5 is produced through: a forming stage for a copper alloy stock; a first heat treatment stage where the copper alloy stock is heated at 700 to 900°C, and is thereafter cooled to ≤300°C at a rate of ≥25°C/min; a second heat treatment stage where heating is performed at 300 to 500°C for 5 min to 5 hr; a rolling stage where rolling at a working ratio of ≤5% per pass is repeated, so as to be the total working ratio of ≥10%; and a third heat treatment stage where heating is performed at 550 to 700°C for 5 sec to 5 min. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high-strength copper alloy material excellent in bending workability and a method for producing the same, and in particular, in a copper alloy material used for electrical and electronic parts such as terminals, connectors, and lead frames, high mechanical strength and good electrical conductivity. The present invention relates to a copper alloy material having excellent properties and excellent bending workability, and a method for producing the same.

  In recent years, various electric and electronic devices have been reduced in size, thickness and weight, and components used therein have been reduced in size. For example, terminal / connector parts are required to be small and have a narrow pitch between electrodes, and the distance between leads of a lead frame tends to be reduced.

  Due to such miniaturization, the material used is thinner, but a material having high strength and high spring property is required because it is necessary to maintain connection reliability even if the material is thin.

  In addition, due to the increase in the number of electrodes and the increase in energization current due to the higher functionality of equipment, the generated Joule heat is becoming enormous, and there is an increasing demand for materials having better conductivity than before.

  Further, along with such downsizing, there is a strong demand for producing smaller and more complicated parts by integral molding, and a material that can be applied to bending under more severe conditions is strongly demanded.

  Conventionally, phosphor bronze has been widely used as a material for electric and electronic parts that require springiness. However, phosphor bronze has a problem that it cannot sufficiently meet the above requirements. That is, since phosphor bronze has a low conductivity of about 20% IACS, it cannot cope with an increase in energization current and has a disadvantage of poor migration resistance. Migration is a phenomenon in which when dew condensation occurs between electrodes, Cu on the anode side is ionized and deposited on the cathode side, eventually leading to a short circuit between the electrodes. It becomes a problem when used in a high-temperature and high-humidity environment such as a connector part for automobiles, and it is also necessary to consider an electric / electronic part whose size is reduced and the pitch between electrodes is narrow.

Therefore, as a material for improving such a problem, a Cu—Ni—Si based copper alloy material is used as a material that can meet demands for higher mechanical strength and conductivity at low cost (for example, Patent Documents 1 to 4). (See Patent Document 5). In a Cu—Ni—Si based copper alloy material, Ni and Si compounds are dispersed and precipitated in the material by heat treatment, thereby making it possible to combine good mechanical strength, springiness, and conductivity.
JP 2002-266042 A Japanese Patent No. 2572042 Japanese Patent No. 2977745 Japanese Patent No. 3465541 Japanese Patent No. 3383615

However, if the Ni and Si compounds are actively precipitated in order to improve the above characteristics, coarse precipitates are likely to be generated. In this case, cracks starting from coarse precipitates are likely to occur during bending, and it is difficult to maintain good bending workability. Also in the invention described in Patent Document 5, the size of “inclusions” including such coarse precipitates is set to 10 μm or less, and the number of inclusions having a size of 5 to 10 μm is 50 in a cross section parallel to the rolling direction. Although the bending workability is improved by controlling to less than pieces / mm ² , further improvement is desired.

  Accordingly, the object of the present invention is to provide mechanical strength equivalent to or better than that of conventional copper alloys (sometimes simply referred to as “strength”. Mechanical strength includes tensile strength and proof stress), springiness, An object of the present invention is to provide a copper alloy material for electric and electronic parts and a method for producing the same, which maintains conductivity and does not cause cracking even in complicated bending processes and has excellent bending processability.

In order to achieve the above object, the present invention is a copper alloy material containing 1.0 to 5.0% by mass of Ni and 0.2 to 1.0% by mass of Si, with the balance being Cu and inevitable impurities. , Regarding the distribution of Ni ₂ Si precipitates observed in a cross section perpendicular to the rolling direction, a surface layer covering a range of up to 20% of the entire plate thickness in the thickness direction from both surfaces of the copper alloy material The number density of the Ni ₂ Si precipitates having a particle size of 0.03 to 3 μm in the sample is a number / mm ² , and the Ni ₂ Si precipitates having a particle size of 0.03 to 3 μm in the inner layer in a range excluding the surface layer. Provided is a copper alloy material wherein the ratio of a / b is 0.5 or less when the number density of objects is b pieces / mm ² .

In order to achieve the above object, the present invention contains Ni in an amount of 1.0 to 5.0 mass%, Si in an amount of 0.2 to 1.0 mass%, and further includes one or both of Zn and Sn in total 5 About the distribution of Ni ₂ Si precipitates observed in a cross section perpendicular to the rolling direction of a copper alloy material that is contained in a range of 0.0 mass% or less and the balance is made of Cu and inevitable impurities, the copper alloy material The number density of the Ni ₂ Si precipitates having a particle size of 0.03 to 3 μm in the surface layer in the thickness direction from both surfaces in a range of up to 20% of the entire plate thickness is a number / mm ² . The ratio of a / b is 0.5 or less when the number density of Ni ₂ Si precipitates having a particle size of 0.03 to 3 μm in the inner layer covering the excluded portion is b pieces / mm ^2. A copper alloy material is provided.

  In order to achieve the above object, the present invention provides a method for producing a copper alloy material according to the present invention, wherein the copper alloy material is formed at a temperature of 700 to 900 ° C. after the copper alloy having the metal composition is formed as a material. The first heat treatment is performed by cooling to 300 ° C. or less at a rate of 25 ° C./min or more, and then the second heat treatment is performed by heating at 300 to 500 ° C. for 5 minutes to 5 hours, followed by one pass. It is characterized in that rolling with a processing rate of 5% or less is repeated to add a rolling process with a total processing rate of 10% or more, and then a third heat treatment is performed by heating at 550 to 700 ° C. for 5 seconds to 5 minutes. A method for producing a copper alloy material is provided.

  According to the present invention, it is possible to provide a copper alloy material having both high mechanical strength, springiness and good electrical conductivity, and also having excellent bending workability.

[Composition of copper alloy material]
The copper alloy material in the present embodiment is a copper alloy material containing 1.0 to 5.0% by mass of Ni and 0.2 to 1.0% by mass of Si in the average composition, and perpendicular to the rolling direction. With respect to the distribution of Ni ₂ Si precipitates observed in a simple cross section, the particle size in the surface layer is 0.03 in a range from the both surfaces of the copper alloy material to 20% of the total plate thickness in the thickness direction. the _Ni 2 Si precipitate the number density a number / mm ² of ～3Myuemu, the _Ni 2 Si precipitates the number density of grain size 0.03~3μm inside layer in the range of parts except the surface layer b pieces / The ratio of a / b when it is ² mm is 0.5 or less.

  In a more preferable embodiment mode, one or both of Zn and Sn are contained in a total amount of 5.0% by mass or less in addition to the above composition.

  In this Embodiment, the reason for addition and limitation of the alloy component which comprises a copper alloy material are demonstrated below.

Ni and Si form a compound represented by Ni ₂ Si and are dispersed and precipitated in the material, thereby increasing the mechanical strength and spring property of the material and maintaining good electrical conductivity. Here, by defining the contents of Ni and Si within the above ranges, it is possible to achieve both high mechanical strength, springiness, and good electrical conductivity more effectively. In addition to Ni ₂ Si, Ni ₅ Si ₂ , Ni ₃ Si, and the like can be considered as a compound of Ni and Si, but in the present invention, it may be considered substantially Ni ₂ Si.

  If the amount of Si added is less than 0.2% by mass, a sufficient amount of Si compound cannot be formed, and satisfactory strength and springiness cannot be obtained. Moreover, when it adds exceeding 1.0 mass%, while having the bad influence of electroconductivity fall, the crack resulting from the segregation of Si compound at the time of casting or hot processing becomes easy to occur. Therefore, the composition range of Si is defined as 0.2 to 1.0 mass%. More desirably, it is specified to be 0.4 to 0.7% by mass.

  In order to effectively form a compound with respect to the Si composition range and to achieve both high strength and high conductivity, it is necessary to define the Ni composition range to 1.0 to 5.0 mass%. When the Ni content is below the lower limit of the composition range, the amount of compound formation becomes insufficient, and the strength and springiness are insufficient. Moreover, when exceeding the upper limit of a composition range, excess Ni will dissolve in copper and will reduce electrical conductivity. More preferably, the composition range of Ni is defined as 2.5 to 3.5% by mass. Here, there is an optimum ratio between the addition amounts of Ni and Si, and the mass ratio of both is Ni / Si = 4. It is desirable to be in the range of -10. In this case, excessive alloy elements that do not form a compound can be reduced. More desirably, it is defined in the range of Ni / Si = 4-6.

  Furthermore, when one or both of Zn and Sn in addition to the above composition is contained within a total range of 5.0% by mass or less, the mechanical strength and spring property can be further improved, and electrical / electronic component materials It is possible to improve plating adhesion, solder wettability, migration resistance, etc. required for the above.

  Zn is a secondary component that has a great effect on improving solder wettability and plating adhesion as well as improving mechanical strength, springiness, and migration resistance. Sn is a secondary component that has the effect of greatly improving the stress relaxation resistance (spring durability and heat resistance) at high temperatures as well as improving mechanical strength and spring properties. However, when these contents exceed 5.0 mass% in total, the adverse effect of lowering the conductivity is increased. Therefore, the composition range of Zn and Sn is specified to be 5.0% by mass or less. More desirably, it is defined as 0.3 to 2.0 mass%.

Next, the reason for limiting the distribution of Ni ₂ Si precipitates observed in the cross section perpendicular to the rolling direction of the copper alloy material in the present embodiment will be described below.

In bending, the largest strain is applied to the surface portion of the material, so that cracking occurs from the vicinity of the surface. Therefore, bending workability can be improved by selectively reducing the Ni ₂ Si precipitates present in the surface layer. Here, as the range of the surface layer, a sufficient effect can be expected if the portion is up to 20% of the entire plate thickness in the thickness direction from the surface.

Ni ₂ Si precipitates with a particle size of 0.03 μm or more are highly likely to act as a starting point of cracks due to concentrated stress, so cracking occurs especially when the surface layer has a large number of such precipitates. Is likely to occur and greatly reduces the bending workability. On the other hand, when it is desired to positively form Ni ₂ Si precipitates for the purpose of improving mechanical strength and electrical conductivity, the generation of precipitates having a particle size of 0.03 μm or more is inevitable. Therefore, in order to suppress the above-described adverse effects, the present invention adopts a method of selectively reducing Ni ₂ Si precipitates present in the surface layer. As a result, it is possible to obtain a material that ensures excellent mechanical strength and electrical conductivity and at the same time has excellent bending workability.

The reason why the particle size of the target Ni ₂ Si precipitates is set to 0.03 to 3 μm is considered not to act as a starting point of cracking for precipitates less than 0.03 μm. Therefore, it is particularly necessary to control the distribution thereof. Because there is no. For large precipitates exceeding 3 μm, most of them are crystallized during the formation of the copper alloy material (particularly during alloy casting), and it is difficult to control the distribution at that time, This is because it is difficult to control the particle size and distribution of precipitates by processing and heat treatment in a subsequent process. However, such a large precipitate (having a particle size exceeding 3 μm) may cause adverse effects such as a decrease in mechanical strength, and therefore it is desirable not to crystallize when forming the copper alloy material.

The ratio of a / b when the number density of precipitates present in the surface layer is a / mm ² and the number density of precipitates present in the inner layer is b / mm ² is defined to be 0.5 or less. The object of the present invention is good mechanical strength and conductivity and excellent bending work when reducing the precipitates present in the surface layer so that the precipitate density of the surface layer is less than half of the inner layer This is because the effect of achieving compatibility is sufficiently obtained. Here, the number density of Ni ₂ Si precipitates is observed at a magnification of about 1000 to 100000 times using a scanning electron microscope, for example, with respect to a cross section perpendicular to the rolling direction of the copper alloy material, and the obtained image is an image. It can be examined by analyzing.

[Method for producing copper alloy material]
FIG. 1 is a diagram showing a flow of a manufacturing process of a copper alloy material according to an embodiment of the present invention. The copper alloy material of the present embodiment is formed by using a copper alloy having the above average composition as a material, and then heating the formed copper alloy material to 700 to 900 ° C., and then at a rate of 25 ° C./min or more. The first heat treatment is performed to cool to below ℃, then the second heat treatment is performed at 300 to 500 ℃ for 5 minutes to 5 hours, and then rolling with a processing rate of 1 pass defined as 5% or less is repeated. It is manufactured by applying a rolling process with a total processing rate of 10% or more and then performing a third heat treatment at 550 to 700 ° C. for 5 seconds to 5 minutes. In addition, the process which consists of an alloy casting process and the hot working process after casting is mentioned as an example for the formation process of a copper alloy raw material.

(First heat treatment)
In the first heat treatment, the formed copper alloy material is first heated to 700 to 900 ° C. and then cooled to 300 ° C. or less at a rate of 25 ° C./min or more. More desirably, after heating to 770-860 ° C., cooling is performed at a rate of 150 ° C./min or more to 300 ° C. or less. Although the holding time at the time of heating and heating is not particularly defined, a shorter one is preferable from the viewpoint of productivity, and it is sufficient that the holding time is substantially held in the temperature range for 1 second or more. The purpose of the first heat treatment is to sufficiently dissolve the alloy element that has formed a coarse crystallized product by heating to a high temperature as a preliminary preparation for obtaining a controlled precipitation state. Here, when the heating temperature is less than 700 ° C., the target crystallized product does not sufficiently dissolve, and when the heating temperature exceeds 900 ° C., the crystal grains become coarse (excessive recrystallization) and mechanical properties (bending processing) Cause a decrease in sex). On the other hand, when the cooling rate is lower than 25 ° C./min, precipitates are generated and grow in the course of cooling, so that the intended controlled precipitation state cannot be obtained.

(Second heat treatment)
In the second heat treatment, heating is performed at 300 to 500 ° C. for 5 minutes to 5 hours to sufficiently precipitate a compound of Ni and Si on the entire surface of the material. More desirably, heating is performed at 400 to 470 ° C. for 1 to 4 hours. The purpose of the second heat treatment is to precipitate a compound of Ni and Si. By this treatment, a compound of Ni and Si is sufficiently deposited on the entire surface of the material, and good mechanical strength, springiness, and conductivity can be realized. Here, if the heating temperature is less than 300 ° C., sufficient precipitation does not occur, and if the heating temperature exceeds 500 ° C., the precipitate becomes too coarse. Note that it is also effective to add cold working after the first heat treatment and then perform the second heat treatment. In this case, since lattice defects (for example, dislocations) introduced into the material by cold working become the starting point of precipitate generation, precipitation can be more effectively advanced (nucleation is likely to occur in lattice defect portions). ).

(Rolling process)
In the rolling process after the second heat treatment, a rolling process with a total processing degree of 10% or more is added by repeating rolling in which the processing degree of one pass is limited to 5% or less. The purpose of this rolling process is to give plastic deformation to the surface layer in a concentrated manner. If the processing rate of one pass is lowered, the surface layer is intensively stretched compared to the inner layer of the material. As a result, unstable precipitates in the surface layer disappear after re-dissolving, and the stable precipitates are also deformed and broken into finer precipitates or changed to a state where they are easily re-dissolved. Can be made. Here, in order to achieve the purpose of intensively applying plastic deformation to the surface layer, it is necessary to reduce the workability of one pass to 5% or less. The same plastic deformation as the layer is added. Further, when the total degree of processing is set to 10% or more, the surface layer precipitates can be sufficiently deformed, and a state in which they are easily re-dissolved by the next heat treatment can be created.

(Third heat treatment)
In the third heat treatment, heating is performed at 550 to 700 ° C. for 5 seconds to 5 minutes to reduce precipitates in the surface layer by re-dissolution. More desirably, heating is performed at 580 to 650 ° C. for 30 seconds to 3 minutes. The purpose of the third heat treatment is to re-dissolve the precipitate in the surface layer that has been made unstable. By this treatment, the precipitate on the surface layer disappears by re-dissolution, and only the precipitate on the surface layer can be selectively reduced while leaving the precipitate on the inner layer. Here, when the heating temperature is less than 550 ° C., the re-solution does not proceed, and when the heating temperature exceeds 700 ° C., the re-solution of the precipitate in the inner layer also proceeds, so that the mechanical strength and the conductivity are lowered.

  By adopting the manufacturing method as described above, a material having a target precipitate distribution can be obtained.

[Effect of the embodiment]
According to the above embodiment of the present invention, the following effects can be obtained.
(1) For electrical and electronic parts that have both high tensile strength exceeding 700 N / mm ² and good electrical conductivity exceeding 40% IACS, and excellent bending workability without cracking even in complicated bending work. A copper alloy material can be obtained.
(2) Due to the nature of the copper alloy material, it is possible to realize a high value of the proof stress of the material by increasing the tensile strength, and as a result, it is possible to ensure a sufficient spring property.
(3) Since it has the excellent properties of (1) and (2) above, it is possible to greatly expand the degree of design freedom in electrical and electronic parts that are becoming smaller.
(4) Despite combining the excellent properties of (1) and (2) above, it can be produced at the same cost as conventional materials.

  EXAMPLES Hereinafter, although this invention is demonstrated in more detail based on an Example, this invention is not limited to these.

[Examples 1 and 2, Comparative Examples 1 to 11]
Sample No. having the alloy composition shown in Table 1 1-No. 2 (Examples 1 and 2) and Sample No. 3-No. 13 (Comparative Examples 1 to 11) were produced under the production conditions shown in Table 3, and their characteristics were evaluated. Each will be described below. In Table 1, inevitable impurities are included in Cu.

Example 1
A copper alloy containing 3.0% by mass of Ni and 0.7% by mass of Si, with the balance being Cu and inevitable impurities was melted in a high-frequency melting furnace and cast into an ingot having a diameter of 30 mm and a length of 250 mm.

  The ingot was heated to 850 ° C. and extruded (hot processing) to form a plate having a width of 20 mm and a thickness of 8 mm, and then cold-rolled to a thickness of 0.5 mm (first cold rolling). Next, after the cold-rolled material was heated to 800 ° C. and held for 10 minutes, it was put into water and subjected to heat treatment to cool to room temperature (about 20 ° C.) at a rate of about 300 ° C./min (first Heat treatment). Next, a heat treatment is performed to hold the cooled material at 450 ° C. for 2 hours (second heat treatment). Subsequently, a cold process is performed to a thickness of 0.3 mm with a pass schedule such that the processing rate of one pass does not exceed 5%. Rolled (second cold rolling). Then, the heat processing hold | maintained at 600 degreeC for 1 minute was performed to this (3rd heat processing) (sample No. 1).

  Sample No. manufactured as described above was obtained. For 1, the tensile strength and conductivity were measured. Regarding the measurement method, the tensile strength was in accordance with JIS Z 2241 and the conductivity was in accordance with the method defined in JIS H 0505. Table 2 shows the measurement results.

As shown in Table 2, sample no. No. 1 indicates that a material having good properties of no ingot cracking, tensile strength of 720 N / mm ² and conductivity of 42% IACS was obtained.

In addition, in the cross section perpendicular to the rolling direction, 10 fields of view are arbitrarily selected from both surface layers from the surface to the thickness direction of 0.06 mm (20% of the plate thickness) and from the inner layer exceeding 0.06 mm from the surface. Then, observation with a scanning electron microscope was performed, and the number of precipitates having a particle size of 0.03 to 3 μm in the observed image was measured using an image analysis apparatus. The ratio of the average precipitate density of the average precipitate density Results obtained surface layer (a number / mm ²⁾ Internal layer (b pieces ^{/ mm 2) (a / b} ) was 0.35. The results are shown in Table 4.

  Further, this sample No. In order to evaluate the bending workability of No. 1, a bending work test was performed according to the V block method of JIS Z2248. As a result of measuring the minimum bending radius r (mm) at which the bending axis is parallel to the rolling direction (Bad way direction) and cracking occurs on the sample surface, the ratio r / t of this r to the thickness t (mm) of the sample The value was 0.50. The results are shown in Table 4. Here, if the value of r / t is 1 or less, there are few problems in normal bending, and it can be said that bending workability is good.

(Example 2)
In addition to Ni: 3.0% by mass, Si: 0.7% by mass, Zn: 1.5% by mass, Sn: 0.3% by mass, with the balance being Cu and inevitable impurities, a copper alloy containing high frequency It was melted in a melting furnace and cast into an ingot having a diameter of 30 mm and a length of 250 mm.

Sample No. manufactured by processing and heat-treating this ingot in the same process as Example 1 (Sample No. 1). For 2, the tensile strength and conductivity were measured in the same manner as in Example 1. As a result, good properties of a tensile strength of 732 N / mm ² and a conductivity of 41% IACS were obtained. As compared with 1, it was possible to obtain a better tensile strength. There was no ingot cracking. The results are shown in Table 2.

  This sample No. Also for No. 2, the number of precipitates was measured in the same manner as described above. As a result, the ratio of the precipitate density of the surface layer to the inner layer (a / b) was 0.35. Similarly, as a result of the bending test, the value of r / t was 0.67. Also in this case, it can be said that the bending workability is good. The results are shown in Table 4.

(Comparative Examples 1-5)
The reason for limiting the alloy composition of the material of the present invention will be described with reference to a comparative example. Copper alloys having the alloy compositions shown in Comparative Examples 1 to 5 in Table 1 were melted in a high frequency melting furnace and cast into ingots having a diameter of 30 mm and a length of 250 mm.

  Sample No. manufactured by processing and heat-treating this ingot in the same process as Example 1 (Sample No. 1). 3-No. For No. 7, the tensile strength and conductivity were measured in the same manner as in Examples 1 and 2. The measurement results are shown in Table 2 together with the presence or absence of ingot cracking.

  Sample No. 3 and no. No. 4 is an example in which the Ni content is out of the specified range. When Ni is excessive, the conductivity value is deteriorated, and when Ni is insufficient, the tensile strength is insufficient.

  Sample No. 5 and no. 6 is an example in which the Si content is out of the specified range. When Si is excessive, the ingot is cracked and processing becomes difficult. Moreover, when Si is insufficient, both conductivity and tensile strength become insufficient.

  Sample No. 7 is an example when Zn and Sn are added excessively. When these subcomponents become excessive, the tensile strength is high but the conductivity is insufficient.

(Comparative Examples 6-11)
Next, the reason for limitation about the manufacturing conditions of the copper alloy material of the present invention will be described using a comparative example. Sample No. 1 of Example 1 For a copper alloy having the same composition as No. 1, after casting and working in the same process as in Example 1, the heating conditions of the first and second heat treatments, the processing rate of one pass in the second cold rolling, and the first No. 3 was processed and heat-treated under the conditions shown in Table 3, and sample No. 8-No. 13 was produced.

  Tensile strength and electrical conductivity were measured for each obtained sample. In addition, sample No. The ratio of the precipitate density of the surface layer and the inner layer was measured by the same method as 1 and the bending workability was evaluated. Table 4 shows the measurement results.

  Sample No. 8 is an example in which the first heat treatment temperature is out of the specified range. If the temperature is too low, the strength becomes insufficient and bending workability is deteriorated.

  Sample No. 9 and no. 10 is an example in which the second heat treatment temperature is out of the specified range. When the temperature is too low, the precipitation is insufficient, and the tensile strength and conductivity are low. On the other hand, when the temperature is too high, the precipitate becomes coarse, resulting in insufficient tensile strength and a decrease in bending workability.

  Sample No. 11 is an example when the processing rate of one pass in the rolling process exceeds 5%. In this case, the difference in precipitate density between the surface layer and the inner layer is small, and the bending workability is lowered.

  Sample No. 12 and no. 13 is an example in which the third heat treatment temperature is out of the specified range. If the temperature is too low, the bending workability will decrease, and if the temperature is too high, the tensile strength and conductivity will be low.

It is a figure which shows the flow of the manufacturing process of the copper alloy material of embodiment of this invention.

Claims (3)

A copper alloy material containing 1.0 to 5.0% by mass of Ni and 0.2 to 1.0% by mass of Si, with the balance being Cu and inevitable impurities, observed in a cross section perpendicular to the rolling direction. With respect to the distribution of Ni ₂ Si precipitates, the Ni having a particle size of 0.03 to 3 μm in the surface layer in the range from the both surfaces of the copper alloy material to 20% of the entire plate thickness in the thickness direction _{2 When the} number density of Si precipitates is a / mm ² , and the number density of Ni ₂ Si precipitates with a particle size of 0.03 to 3 μm in the inner layer in the range excluding the surface layer is b / mm ² A copper alloy material, wherein the ratio of a / b is 0.5 or less. Ni is contained in an amount of 1.0 to 5.0% by mass, Si is contained in an amount of 0.2 to 1.0% by mass, and one or both of Zn and Sn are contained within a total range of 5.0% by mass or less, and the balance is Regarding the distribution of Ni ₂ Si precipitates observed in a cross section perpendicular to the rolling direction of a copper alloy material made of Cu and unavoidable impurities, each of the entire plate thickness in the thickness direction from both surfaces of the copper alloy material is 20 The number density of the Ni ₂ Si precipitates having a particle size of 0.03 to 3 μm in the surface layer in the range of up to% is a / mm ² , and the particle size in the inner layer in the range excluding the surface layer is 0 A copper alloy material, wherein the ratio of a / b is 0.5 or less when the number density of the Ni ₂ Si precipitates of 0.03 to 3 μm is b pieces / mm ² . It is a manufacturing method of the copper alloy material according to claim 1 or 2,
After the copper alloy having the composition shown in claim 1 or 2 is formed as a raw material, the copper alloy raw material is heated to 700 to 900 ° C, and then cooled to 300 ° C or lower at a rate of 25 ° C / min or higher. No. 1 heat treatment, followed by a second heat treatment at 300 to 500 ° C. for 5 minutes to 5 hours, followed by repeated rolling with a 1 pass processing rate of 5% or less, resulting in a total processing rate of 10% or more. A method for producing a copper alloy material is characterized in that a third heat treatment is performed by heating at 550 to 700 ° C. for 5 seconds to 5 minutes.

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