JPH11222641A - Copper alloy for elctrically conductive spring and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper alloy combining excellent mechanical properties, conductivity, stress relaxation characteristics and bending workability. SOLUTION: This copper alloy is the one having a compsn. contg., as essential components, by weight, 1.0 to 3.5% Ni, 0.2 to 0.9% Si, 0.01 to 0.20% Mg and 0.05 to 1.5% Sn, in which each content of S and O is limited to <0.005%, and the balance Cu with inevitable impurities, and the grain size thereof is regulated to >1 to 25 μm. Thus, this is suitable for terminals, connector materials and switch materials. Furthermore, as for the method for producing it, after cold working, recrystallization treatment is executed at 700 to 920 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper alloy for a conductive spring and a method for producing the same, and particularly to a terminal / connector material,
The present invention relates to a conductive spring copper alloy suitable for a switch material and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, copper alloys have been used as materials for terminals and connectors, and Cu-Zn-based alloys, Cu-Fe-based alloys having excellent heat resistance, and Cu-Sn-based alloys have been widely used. In particular, inexpensive Cu-Zn-based alloys are often used in applications such as automobiles, but in recent years automobile terminals and connectors have been significantly reduced in size, and may be exposed to severe environments such as in an engine room. Cu-Z
Cu-Fe based alloy, Cu
At present, it is becoming impossible to cope with -Sn alloys.

As described above, the characteristics required for the terminal and connector materials have become more severe as the environment in which they are used changes. Copper alloys used for such applications have a wide variety of properties such as stress relaxation properties, mechanical strength, thermal conductivity, bending workability, heat resistance, connection reliability of Sn plating, and migration properties. Important properties are mechanical strength, stress relaxation properties, thermal and electrical conductivity, and bending workability.

As a copper-based material satisfying these strictly required characteristics, a Cu-Ni-Si-based alloy has attracted attention, and for example, Japanese Patent Application Laid-Open No. 61-127842 is known. However, even such a Cu-Ni-Si alloy falls into a state where it cannot withstand use. Specifically, when the size of components is reduced, for example, in a general box-shaped terminal, the tab width of the inserted male terminal is reduced from the 090 terminal having a tab width of about 2 mm to the 040 terminal having a tab width of about 1 mm, The width is about 1 mm, and when the components are miniaturized in this way, it is difficult to obtain a sufficient connection strength. Also, in order to secure the connection strength at the spring part in connection with miniaturization, many efforts have been made on the structure of the terminal, but as a result, the bending workability required for the material has become more severe. Therefore, cracks often occur in the bent portion in the conventional Cu-Ni-Si. The same applies to the stress relaxation characteristics, and it is impossible to use the conventional Cu-Ni-Si-based alloy for a long time due to an increase in the stress applied to the material and an increase in the use environment.

Under these circumstances, the addition of Mg is effective, for example, to improve the stress relaxation characteristics. For example, JP-A-61-250134, JP-A-5-59468, and the like also show that Mg is effective. Sex is shown. However, although the stress relaxation characteristics are improved by the addition of Mg, the bending workability is deteriorated, and the material cannot withstand 180 ° close contact bending. Therefore, the improvement of the bending workability is indispensable for use in automotive connectors and the like. In addition, studies have been made to improve bending workability, but since these materials are low in strength, desired characteristics cannot be obtained. Furthermore, if heat and electricity conductivity is poor, even if the stress relaxation property is good, stress relaxation is promoted by self-heating, so that the balance between the conductivity and the stress relaxation property is important.

[0006]

As described above, a copper-based material satisfying strict requirements has been proposed by examining bending workability, stress relaxation characteristics, and the like, but the present invention provides excellent mechanical properties. It is a copper alloy having both conductivity, stress relaxation characteristics and bending workability, and provides a copper alloy suitable for terminals and connectors.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and contains Ni as a main component in an amount of 1.0 to 3.5 wt.
%, 0.2-0.9 wt% of Si, 0.01-% of Mg
0.20 wt%, Sn containing 0.05-1.5 wt%,
A copper alloy for a conductive spring, wherein the S and O contents are each limited to less than 0.005 wt%, the balance being Cu and unavoidable impurities, and having a crystal grain size of more than 1 μm and 25 μm or less. In the above configuration,
As long as the characteristics of the present invention are not adversely affected, other additive elements, for example, Zn of less than 0.2% may be added. In addition, the present invention provides, as main components, 1.0 to 3.5 wt% of Ni, 0.2 to 0.9 wt% of Si,
0.01 to 0.20 wt% Mg, 0.05 to Sn
1.5 wt%, containing 0.2 to 1.5 wt% of Zn, S,
The O content is limited to less than 0.005 wt%, and the balance consists of Cu and unavoidable impurities.
It is a copper alloy for conductive springs, having a thickness of more than μm and not more than 25 μm.

[0008] The present invention also relates to the above-mentioned copper alloy, wherein one or more selected from Ag, Mn, Fe, Cr, Co, and P are added in a total amount of 0.005 wt% to 2.0 wt%.
% Is a copper alloy. Specifically, as main components, 1.0 to 3.5 wt% of Ni and 0.2
~ 0.9wt%, Mg 0.01 ~ 0.20wt%, S
n is 0.05 to 1.5 wt%, and 0.005 to
0.3 wt% Ag, 0.01-0.5 wt% Mn, 0.005-0.2 wt% Fe, Cr, 0.05 respectively
~ 2.0wt% Co, 0.005 ~ 0.1wtP
% To 2.0 wt%, and the S and O contents are each 0.0%.
A copper alloy for a conductive spring, which is limited to less than 05 wt%, the balance being Cu and unavoidable impurities, and having a crystal grain size of more than 1 μm and 25 μm or less. Further, as main components, 1.0 to 3.5 wt% of Ni, 0.2 to 0.9 wt% of Si, and 0.01 to 0.20 wt% of Mg.
%, Sn is 0.05-1.5 wt%, Zn is 0.2-
1.5wt%, 0.005 ~ 0.3wtA
g, 0.01-0.5 wt% Mn, each 0.005
-0.2 wt% Fe, Cr, 0.05-2.0 wt%
Co, one or more selected from 0.005 to 0.1 wt% P, in a total amount of 0.005 wt% to 2.0 wt%
Copper alloy for conductive springs, characterized in that the content of S and O is limited to less than 0.005 wt%, the balance being Cu and unavoidable impurities, and the crystal grain size of which exceeds 1 μm and is 25 μm or less. It is.

In the present invention, one or more of Pb and Bi may be further added to the above copper alloy in a total amount of 0.005 to 0.5%.
It is a copper alloy characterized by containing 13 wt%. Specifically, 1.0 to 3.5 wt% of Ni as a main component, Si
0.2 to 0.9 wt%, Mg 0.01 to 0.20 w
t, 0.05 to 1.5 wt% of Sn,
005 to 0.1 wt% Pb, 0.005 to 0.03 wt
One or two kinds of Bi in a total amount of 0.005 to 0.13 w
Copper for conductive springs, wherein the content of S and O is limited to less than 0.005 wt%, and the balance is made of Cu and unavoidable impurities, and the crystal grain size is more than 1 μm and 25 μm or less. Alloy. Further, as main components, Ni is 1.0 to 3.5 wt%, and Si is 0.2 to 0.9 wt%.
wt%, Mg: 0.01 to 0.20 wt%, Sn: 0.
0.5 to 1.5 wt%, contains 0.2 to 1.5 wt% Zn, and further contains 0.005 to 0.1 wt% Pb and 0.005 wt%.
0.003 wtBi of one or two kinds in a total amount of 0.00
5 to 0.13 wt%, and the S and O contents are each 0.1%.
A copper alloy for a conductive spring, which is limited to less than 005 wt%, the balance being Cu and unavoidable impurities, and having a crystal grain size of more than 1 μm and 25 μm or less.

In addition, Ag, M
one or two selected from n, Fe, Cr, Co, P
Or more and one or two of Pb and Bi in a total amount of 0.1.
It is a copper alloy characterized by containing 005 wt% to 2.0 wt%. Specifically, Ni as a main component is 1.0 to
3.5 wt%, Si 0.2-0.9 wt%, Mg 0.01-0.20 wt%, Sn 0.05-1.5 w
t%, 0.005 to 0.3 wt% Ag,
01 to 0.5 wt% Mn, each 0.005 to 0.2
wt% Fe, Cr, 0.05-2.0 wt% Co,
One or more selected from 0.005 to 0.1 wt% P, and 0.005 to 0.1 wt% Pb, 0.0
0.5 to 0.03 wtBi in total.
005 wt% to 2.0 wt%, the S and O contents are each limited to less than 0.005 wt%, and the balance consists of Cu and unavoidable impurities, and the crystal grain size exceeds 1 μm and exceeds 25 μm.
It is a copper alloy for a conductive spring, which is not more than μm. Also, 1.0 to 3.5 wt% of Ni as a main component.
%, 0.2-0.9 wt% of Si, 0.01-% of Mg
0.20 wt%, 0.05 to 1.5 wt% Sn, Zn
Is contained in an amount of 0.2 to 1.5 wt%, and 0.005 to 0.
3 wt% Ag, 0.01-0.5 wt% Mn, 0.005-0.2 wt% Fe, Cr, 0.05-
2.0 wt% Co, one or more selected from 0.005 to 0.1 wt% P, and 0.005 to 0.1
wt% Pb, containing 0.005 wt% to 2.0 wt% in total of one or two of 0.005 to 0.03 wtBi,
A copper alloy for a conductive spring, wherein the S and O contents are each limited to less than 0.005 wt%, the balance being Cu and unavoidable impurities, and having a crystal grain size of more than 1 μm and 25 μm or less.

Further, the copper alloy of the present invention is used for any of terminals, connector materials, and switch materials. Further, the present invention is a method for producing a copper alloy for a conductive spring, wherein a recrystallization treatment is performed at 700 to 920 ° C. after cold working. Also,
A method for producing a copper alloy for a conductive spring, comprising performing recrystallization treatment at 700 to 920 ° C. after cold working and then aging at 420 to 550 ° C. The treatment is performed at 700-920 ° C.,
% Or less, and then aging treatment at 420 to 550 ° C. after cold working is performed. Further, after the cold working, a recrystallization treatment
0-920 ° C, then cold working up to 25%, 42
After aging treatment at 0 to 550 ° C., 25%
A method for producing a copper alloy for a conductive spring, comprising performing the following cold working and low-temperature annealing.

[0012]

The copper alloy of the present invention contains Ni in a Cu matrix.
And a compound of Si, with appropriate mechanical strength and heat
Specific amounts of Sn, Mg, and Zn are added to a copper alloy having electrical conductivity to limit the S and O contents and to reduce the grain size to 1
The main point is to improve the stress relaxation characteristics and bending workability by setting the thickness to more than 25 μm and more than 25 μm. The present inventors provide a copper alloy for a conductive spring having practically excellent properties, particularly a terminal and a material having excellent properties for a connector by defining the content of the copper alloy component in detail. Have been found, and as a result, the copper alloy of the present invention has been obtained.

The reasons for limiting the components of the copper alloy of the present invention will be described below. When Ni and Si are contained in Cu, a Ni—Si compound is produced, which is precipitated in Cu to improve strength and electrical conductivity. If the amount of Ni is less than 1.0 wt%, the amount of precipitation is small and the target strength cannot be obtained. Conversely, if the Ni content exceeds 3.5 wt%, precipitation not contributing to the increase in strength occurs during casting and hot working, so that not only the strength corresponding to the content cannot be obtained, but also the hot workability and bending workability are adversely affected. Will be given. Since the amount of Si is considered that the compound of precipitated Ni and Si is in a Ni ₂ Si phase,
When the amount of Ni is determined, the optimum Si content is determined. If the amount of Si is less than 0.2 wt%, sufficient strength cannot be obtained as in the case where the amount of Ni is small. Conversely, when the Si content exceeds 0.9 wt%, the same problem occurs as when the Ni content is large. Preferably, Ni is 1.7 to 2.8 wt.
% And Si are preferably adjusted to 0.4 to 0.7 wt%.

Mg and Sn are important additional elements constituting the copper alloy of the present invention. These elements are mutually related to achieve a good property balance. Next, the reasons for limiting these elements will be described. Although Mg significantly improves stress relaxation properties, it has an adverse effect on bending workability. From the viewpoint of stress relaxation characteristics, the content is preferably as high as 0.01 wt% or more. On the other hand, from the viewpoint of bending workability, the content is preferably 0.1%.
If it exceeds 20 wt%, it is difficult to obtain good bending workability. From such a viewpoint, the content range of Mg is 0.1.
A good balance is shown at 01 to 0.20 wt%.
A more preferable Mg content range from the viewpoint of bending workability is:
It is 0.01 to 0.1 wt%.

Furthermore, it has been found that by adding Sn, the stress relaxation characteristics can be further improved while maintaining good bending workability. Although Sn has the effect of improving the stress relaxation characteristics, the effect is not as great as that of Mg.
It shows a good characteristic balance in correlation with g. If Sn is contained in excess of 1.5 wt%, the thermal and electrical conductivity will be degraded, causing a practical problem. Although the Sn content has a balance with the Mg content, the Sn content is 0.05 to 1.5.
A good property balance is shown at wt%. Specifically, Mg
Is 0.01 to 0.05 wt%, Sn is 0.8
To 1.5 wt%, and the Mg content is 0.05 to 0.1%.
In the case of wt%, Sn is preferably 0.05 to 0.8 wt%.

Although Zn does not contribute to the stress relaxation characteristics, it can improve the bending workability. 0.2-1.5 Zn
By containing 0.3 wt%, preferably 0.3 to 1.0 wt%, a level of bending workability that does not pose a practical problem can be achieved even when Mg is contained up to a maximum of 0.20 wt%. Also Z
n has the effect of improving the heat-peeling resistance and migration characteristics of Sn plating and solder plating, and also has the effect of improving punching workability.
t%, preferably 0.3 wt% or more. Elements that improve the punching workability include P
There are b and Bi, but when Pb and Bi are added in a large amount, hot workability is impaired, but Zn is an effective additive element because it can improve punching workability without adversely affecting the productivity. The upper limit is 1.5w considering thermal and electrical conductivity.
t%, preferably 1.0 wt%. This example also shows that co-addition with Mg has a better tendency.

Although the reasons for limiting the addition ranges of Mg, Sn and Zn have been described in detail above, it is not preferable to set the respective maximum contents within the limited ranges of these elements. In practice,
The most well-balanced content range is Mg: 0.05.
0.15 wt%, Sn: 0.2-0.5 wt%, Z
n: 0.3 to 0.8 wt%.

Next, Ag, Mn, Fe, Cr, Co, P
The reason for limiting the range of the content of is described. Ag, M
n, Fe, Cr, Co, and P have similar functions in terms of improving workability, and include Ag, Mn,
One or more selected from Fe, Cr, Co, and P are contained at 0.005 wt% to 2.0 wt%.

Ag can increase the heat resistance and the strength, and at the same time, can prevent the crystal grains from becoming coarse and improve the bending workability. Heretofore, it has been attempted to add various third elements in order to increase the strength of Cu-Ni-Si alloys. It deteriorated and exhibited unfavorable characteristics for use in electronic devices. The present invention
As a result of repeating examination of elements that improve strength and do not adversely affect other characteristics, they have found that Ag is effective. If the content is less than 0.005% by weight, the effect is not exhibited. Conversely, if the content exceeds 0.3% by weight, there is no adverse effect on the characteristics, but the cost increases, so the optimal content of Ag is 0.005%. To 0.3 wt%, more preferably 0.005 to 0.1 wt%.

Mn has the effect of improving the hot workability at the same time as increasing the strength. If the content is less than 0.01 wt%, the effect is small, and even if the content exceeds 0.5 wt%, the content is increased. In addition to not being able to obtain the effect corresponding to
Deteriorates conductivity. Therefore, the optimal content range of Mn is
0.01 to 0.5 wt%, more preferably 0.0 to 0.5 wt%.
3 to 0.3 wt%.

Fe and Cr combine with Si to form Fe-Si
Compounds and Cr-Si compounds are formed to increase the strength.
Further, there is an effect of trapping Si remaining in the copper matrix without forming a compound with Ni and improving conductivity. Since Fe-Si compounds and Cr-Si compounds have low precipitation hardening ability, it is not advisable to produce many compounds. On the other hand, if the content exceeds 0.2 wt%, the bending workability deteriorates. From these viewpoints, when Fe and Cr are contained, the addition amount is 0.005 to 0.2 wt%, and more preferably 0.005 to 0.1 wt%.

Co forms a compound with Si similarly to Ni, and improves mechanical strength. Since Co is more expensive than Ni, the present invention uses a Cu-Ni-Si alloy. However, if cost is acceptable, Cu-C
An o-Si system or a Cu-Ni-Co-Si system may be selected. Cu-Co-Si system, when aging precipitation, Cu
-Both mechanical strength and electrical conductivity are slightly better than those of the Ni-Si system. Therefore, it is effective for members in which thermal and electrical conductivity is important. Further, since the Co—Si compound has a slightly higher precipitation hardening ability, the stress relaxation property tends to be slightly improved. From these viewpoints, the optimum addition amount when Co is added is 0.05 to 2.0 wt%.

P has the effect of increasing the strength and at the same time improving the conductivity. A large amount promotes grain boundary precipitation and lowers bending workability. Therefore, the optimum content range when P is added is 0.005 to 0.1 wt%, and more preferably 0.005 to 0.05 wt%. When two or more of these are added at the same time, they may be appropriately determined according to the required characteristics.
The total amount was set to 0.005 to 2.0 wt% from the viewpoints of solder plating heat resistance, conductivity and the like.

Next, the reason for limiting the range of the content of Pb and Bi will be described. Pb and Bi improve punching workability, and one or two of Pb and Bi are 0.00
It contains 5 to 0.13 wt%. Pb is an additive element for improving the punching workability. With the recent increase in the speed of pressing, more excellent workability is required for terminal materials. Pb is dispersed in the copper matrix and serves as a starting point for destruction, thereby improving the punching workability. If the amount of Pb is less than 0.005 wt%, there is no property improving effect,
If added in excess of 0.1 wt%, not only the hot workability is reduced, but also the bending workability is deteriorated.
005 to 0.1 wt% is optimal, and more preferably 0.005 to 0.05 wt%. Bi is also an additive element for improving the punching workability. If the content is less than 0.005 wt%, the effect of improving the properties is small, and if it exceeds 0.03 wt%, the same property deterioration as Pb is caused. Therefore Bi
Is 0.005 to 0.03 wt%, more preferably 0.005 to 0.02 wt%.

These Ag, Mn, Fe, Cr, Co, P
When one or two or more selected from Pb and Bi and one or two of Pb and Bi are contained at the same time, heat resistance, Sn plating, soldering, and the like may be appropriately determined according to the required properties. The total amount was 0.005 to 2.0 wt% from the viewpoints of plating heat resistance, conductivity and the like.

Next, the reason why the S and O contents are limited to less than 0.005 wt% will be described. Normally, industrial copper materials contain trace amounts of S, O _2, etc., but the present invention restricts these contents strictly to provide excellent characteristics in combination with the above-mentioned alloy components and the definition of crystal grain size described below. Is to be realized. S is an element that deteriorates hot workability,
By specifying the content as less than 0.005 wt%,
Improves hot workability. Especially S content is 0.002w
It is desirable to make it less than t%. If the content of O is 0.005 wt% or more, Mg is oxidized and bending workability is deteriorated. O content 0.005 wt% or less,
In particular, the content is desirably less than 0.002 wt%. Although S and O described above are often contained in trace amounts in ordinary copper-based materials, they are particularly important in the copper alloy of the present invention, and excellent properties can be obtained by regulating the contents. It has been found that it achieves characteristics suitable for terminal and connector materials.

In the structure of the copper alloy of the present invention described above,
In order to suitably realize the characteristics, the crystal grain size is 1 μm
Over 25 μm. When the crystal grain size is 1 μm or less, it is easy to form a mixed grain in the recrystallized structure, and the bending workability is lowered and the stress relaxation property is lowered. Conversely, even if the grain size grows beyond 25 μm,
This has an adverse effect on bending workability. Therefore, the grain size is 1μ
It is necessary to adjust the thickness to more than m and 25 μm or less.

Next, a method for producing the copper alloy of the present invention will be described. The copper alloy of the present invention is subjected to heat treatment for the purpose of recrystallization and solution treatment after cold working, for example, cold rolling, and is immediately quenched. Further, aging processing is performed as needed. In order to adjust the crystal grain size in the copper alloy of the present invention to a range of more than 1 μm and 25 μm or less,
It is necessary to control the conditions of the recrystallization treatment in detail. 700
Heat treatment at a temperature lower than ℃ is 920 ° C.
If the temperature exceeds the limit, the crystal grains are likely to grow coarsely, so that the recrystallization treatment is performed at 700 to 920 ° C. after the cold working. The cooling rate is as fast as possible at 10 ° C / s.
It is desirable to cool at the above speed.

Next, regarding the condition of the aging heat treatment, if the aging temperature is lower than 420 ° C., the amount of precipitation hardening is insufficient, and sufficient characteristics cannot be obtained. 550
When treated at a temperature exceeding ℃, the precipitated phase grows coarsely,
Not only does the strength decrease, but also the stress relaxation characteristics. Therefore, the aging treatment temperature was set to 420 to 550 ° C. Furthermore, it has been found that the stress relaxation characteristics are greatly affected by the state of the precipitated phase, and the best condition is near the temperature at which the aging strength shows a peak. On the other hand, as for bending workability, it is desirable to perform the heat treatment on the slightly overaged side from the temperature at which the aging strength shows a peak. From such a viewpoint, preferably 46
Processing at 0-530 ° C. is optimal.

Further, recrystallization treatment (solution solution) after cold working
At 700 to 920 ° C., and after further cold working (25% or less), aging at 420 to 550 ° C. In the examples described later, the aging treatment was performed immediately after solution treatment, but it is also effective to perform cold working between solution treatment and aging. In this case, it is desirable to perform processing with a cross-sectional reduction rate of 25% or less that does not deteriorate bending workability. Also,
700-920 ° C after recrystallization treatment (solution solution) after cold working
Cold working (25% or less), after aging treatment at 420 to 550 ° C, further cold working of 25% or less,
And low-temperature annealing. Thus, cold working may be performed after the aging treatment. In this case, in order not to deteriorate the bending workability, which is a feature of the present invention, it is desirable to perform processing with a cross-sectional reduction rate of 25% or less. Furthermore, when performing cold working after the above-mentioned aging treatment, it is recommended to perform annealing at a relatively low temperature thereafter. When performing this annealing by batch type annealing, at a temperature of 250 to 400 ° C. for 0.5 to 5 hours.
r, when performing annealing during running, it is desirable to perform at a temperature of 600 to 800 ° C. for 5 to 60 s. This annealing has the effect of rearranging the dislocations introduced in the cold working and consequently suppressing the movement of the dislocations. Therefore, when the above-mentioned cold working is performed, the stress relaxation characteristics can be improved by annealing. If necessary, before or after the final heat treatment, a correction such as a tension leveler or a roller leveler may be performed.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION The copper alloy of the present invention has excellent mechanical strength, bending workability, stress relaxation property, Sn plating releasability,
It has a punching property and the like, and particularly has characteristics required for a general conductive material such as a terminal / connector material, a switch material, a relay material, etc., and will be described in detail with reference to Examples.

[0032]

Embodiment 1 A first embodiment of the present invention will be described with reference to Tables 1 to 6. Table 1 shows the alloy compositions of the examples of the present invention, Tables 2 and 3 show the alloy compositions of the comparative examples and the conventional examples, Table 4 shows the properties of the alloys of the present invention, Tables 5 and 6 show the alloys of the comparative examples and the conventional examples. This shows the characteristics of The arrows in the table indicate the same as those in the upper column, and (*) indicates that the test was stopped because the yield strength was low and plastic deformation occurred at the sample setting stage.

First, alloys having the compositions shown in Tables 1 to 3 were melted in a high-frequency melting furnace and cast at a cooling rate of 6 ° C./s.
The size of the ingot is 30 mm in thickness, 100 mm in width, and 15 in length.
0 mm. Next, these ingots were hot-rolled at 900 ° C., and then immediately cooled. After removal of the oxide film on the surface, the surface was cut to a thickness of 9 mm, and then worked by cold rolling to a thickness of 0.25 mm. Thereafter, a heat treatment was performed at 750 ° C. for 30 seconds, and quenching was immediately performed at a cooling rate of 15 ° C./s or more in order to recrystallize and solution-treat the test material. In the aging treatment, a heat treatment was performed at 515 ° C. for 2 hours in an inert atmosphere to obtain a material to be subjected to the test.

The crystal size is measured by sampling from the manufactured material, and TS (tensile strength) N / mm ² , El
(Elongation)%, EC (conductivity)% IACS, bending workability,
S. R. Various characteristics such as R (stress relaxation rate)%, Sn plating releasability, and punching properties were evaluated for fracture surface ratio (%) and burr (μm).

The crystal grain size, that is, the size of the crystal grain is determined according to JIS.
Observation was performed according to H0501 using both the comparison method and the cutting method. In the comparative method, the specimen was observed under a microscope (75 times or 20 times).
0). In the cutting method, the measurement was performed on a section having a plate thickness parallel to the processing direction. The tensile strength is JISZ2241
In JIS, electrical conductivity is used as a value indicating thermal and electrical conductivity.
It was measured according to H0505.

The bending workability was evaluated by determining whether the inner bending radius was OR
180 ° close bending. The evaluation index is as follows. Good without wrinkles C. Small wrinkles are observed. A large wrinkle was observed, but no crack was observed. E. Fine cracks are observed. Evaluation was made on a scale of 1 to 5 in which cracks were clearly observed, and a rating of C or higher was judged as a level having no practical problem.

The evaluation of the stress relaxation characteristics was carried out in accordance with EMAS-3003, which is a standard of the Electronic Materials Industries Association of Japan. Here, a cantilever block type is adopted, and the applied stress is set so that the surface maximum stress is 450 N / mm ² ,
The test was performed in a thermostat at 0 ° C. In Tables 4 to 6, 100
The relaxation rate (SRR) after the 0 hr test was shown.

FIGS. 1A, 1B and 1C show the cantilever block method of the stress relaxation test method. FIG. 1A is a perspective view, and FIG. 1B is a side view. One of the samples (1) is supported on a base (2) by a holding member (3) in a cantilever state.
The other is brought into a state in which the sample (1) is given a strain δo (initial deflection displacement) by the block (4). In this state, the sample (1) is heated to 150 ° C. for a predetermined time (1000 hours in this embodiment). After a lapse of a predetermined time, FIG.
As shown in the side view, the strain δt (permanent flexural displacement) with the block (4) removed was measured, and the stress relaxation rate (%) was obtained by the following equation. Stress relaxation rate (%) = (δt / δo) × 100 Incidentally, the initial deflection displacement is such that the maximum surface stress is a predetermined value (4
It is calculated from Young's modulus, plate thickness, and the like so as to be 50 N / mm ² ) (the calculation method is based on EMAS-3003).

The heat-peeling property of the Sn plating was as follows. A test piece coated with a 1 μm glossy Sn plating was heated at 150 ° C. for 1000 hours in the air, and then bent 180 ° in close contact and bent back. Was visually evaluated for plating peeling. When the peeling of the solder was recognized, "Yes" was described in Tables 4 to 6.

The punching property was examined by performing a punching test (providing a square hole of 1 mm × 5 mm) with a mold (manufactured by SKD11). Then, the thickness of the fractured part was measured by observing the punched surfaces of 20 randomly extracted samples from the 5001st to 10000th punchings. Table 4-
6 shows the average value of the ratio of the thickness of the fractured portion to the thickness of the test piece in% (shown as FAR in the table). Similarly, for the burr measurement, the heights of the burr of 20 randomly extracted samples from the 5001st to 10000th punched portions were determined by a contact type shape measuring instrument, and the average value was described in the table.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

As is clear from Table 4, Examples 1 to 2 of the present invention
1 is TS (tensile strength), El (elongation), EC (conductivity), bending workability, S.I. R. It can be seen that R (stress relaxation rate), Sn plating releasability, and punching properties all show excellent properties.

On the other hand, in Comparative Example No.
In No. 22, the intended strength was not obtained, and the punching workability was inferior to other materials. Conversely, Comparative Example No. No. 23 of the present invention example No. 23 having a small amount of Ni-Si. Although there was no difference in strength in comparison with No. 4, the bending workability showed a tendency to deteriorate. That is, the addition of Ni-Si in an amount equal to or more than the amount specified in the present invention is inferior in bending workability, and thus is not suitable for terminals and connectors.

Comparative Example No. 24
Is No. of the present invention example. 2, No. As compared with No. 5, the stress relaxation property was significantly inferior. Comparative Example N for the same reason
o. No. 25 is Example No. 25 of the present invention. 6, No. Inferior to 7. This indicates that even if Sn is solely added to the conventional Cu-Ni-Si alloy (conventional example No. 42), a large improvement effect on the stress relaxation characteristics cannot be expected. Cu-Ni-Si alloy (conventional example N
o. 43).

Comparative Example No. 1 in which the amount of Mg added was not less than the specified amount of the present invention. No. 26 has deteriorated bending workability. This is unsuitable as a terminal / connector material. Good bending workability could not be ensured even when 1 wt% or more of Zn, which can slightly improve the bending workability, was added. Comparative Example No. No. 27 of the present invention example. Compared to 2,
Poor in terms of stress relaxation characteristics. Conversely, Comparative Example No. No. 28 was one of the compositions exhibiting the most excellent stress relaxation characteristics in this production, combined with the effect of Mg. However, the conductivity is the lowest, and it cannot be said that it is excellent in balance. Comparative Example No. 29 also has a low conductivity and is not excellent in the property balance.

Comparative Example N in which the amount of Fe added was not less than the specified amount
o. In No. 30, not only a large amount of Fe-Si compound was generated, the precipitation hardening amount was reduced, but also the bending workability was adversely affected. Comparative Example No. 1 in which the added amount of Pb was increased. No. 31 cracked during hot working and could not be manufactured normally. In addition, Comparative Example No. S in which S is out of the range of the present invention.
In No. 32, cracks occurred during hot working, and subsequent characteristic evaluation could not be performed. Further, in Comparative Example No. 33 is M
g of oxide was generated, and the bending workability was deteriorated.

Comparative Example No. In No. 34, annealing for recrystallization was performed at 680 ° C. × 30 s. As a result, the average crystal grain was 1 μm or less, and a structure in which relatively large crystal grains and small crystal grains were mixed was obtained. Due to the non-uniform structure, cracking occurred depending on the place where the test piece to be subjected to bending workability was collected. Conversely, Comparative Example No. 35 is 93
Since the heat treatment was performed at 0 ° C. × 30 s, the crystal grains were about 3
It was 0 μm. The coarse crystal grains not only adversely affected bending workability but also slightly reduced stress relaxation characteristics.

In Comparative Example No. 36-No. 41 is C
This is a comparative example in which an element other than Sn is added to a u-Ni-Si-Mg-Zn alloy. Regarding the stress relaxation characteristics of each of these alloys, Comparative Example No. It has a stress relaxation characteristic comparable to that of No. 27, indicating that the addition of these elements hardly contributes to stress relaxation.

Next, the conventional alloys will be described. Reference numeral 42 denotes a Cu-Ni-Si alloy, which does not include other additional elements. In this case, since the stress relaxation property is not good and Zn is not included, Sn
There is a problem with the heat peelability of plating. Conventional example No. 43 is a material obtained by adding Sn and Zn to a Cu-Ni-Si alloy as described above. Although the heat-peeling property of the Sn plating is improved, the stress relaxation property is the same as that of the conventional example. Equivalent to 41, insufficient.

No. Reference numeral 44 denotes a material to which Mg is added to improve stress relaxation characteristics. Although the stress relaxation property is improved by the effect of Mg, there is a problem in bending workability.
This conventional example No. In order to obtain the same stress relaxation characteristics and good bending workability as those of Example No. 44 of the present invention. Like 2,
This is achieved by reducing the amount of Mg, adding Sn, and further adding Zn which improves bending workability. Due to the Zn addition effect, the heat peelability of Sn plating is also improved.

[0050]

Embodiment 2 A second embodiment of the present invention will be described with reference to Tables 7 and 8. The second embodiment corresponds to the present invention example No. 1 shown in the first embodiment. An alloy having the composition of No. 2 was manufactured by the steps shown in Table 7, and as shown in Table 8, TS (tensile strength) N / m
m ² , El (elongation)%, EC (conductivity)% IACS, bending workability, S.M. R. R (stress relaxation rate)%, Sn plating peeling property, punching property A. R (%), burr (μ
m) were evaluated. The evaluation method is the same as in the first embodiment.

[Table 7]

[Table 8]

As is apparent from Tables 7 and 8, the alloy of the present invention No. No. 45-N
o. No. 53 showed excellent characteristics. However,
Comparative Example No. In No. 54, the heat treatment temperature was low, and as a result, the crystal grains were not uniform, and the bending workability was deteriorated. Comparative Example No.
In the case of No. 55, since the heat treatment was performed at 930 ° C. × 30 s, the crystal grains became approximately 30 μm. The coarse crystal grains not only adversely affected the bending workability but also slightly reduced the stress relaxation characteristics.

Comparative Example No. In No. 56, the aging temperature was low, and the precipitation was insufficient, so that the strength characteristics were deteriorated. At the same time, the stress relaxation characteristics were significantly reduced. Conversely, No. In No. 57, the aging temperature was high and the precipitates were coarsened, so that the stress relaxation characteristics were significantly reduced. Comparative Example No. Reference numeral 58 denotes an example in which cold working is performed after the aging at a working ratio higher than that specified in the present invention. Although the stress relaxation characteristics were rather excellent, the bending workability was lowered. Comparative Example N
o. 59 is an example in which the cold working ratio after aging is not high, but the heat treatment is not performed thereafter. Not only the elongation was low and the bending workability was lowered, but also the stress relaxation properties were slightly lowered.

[0053]

As described above, in the copper alloy of the present invention, a compound of Ni and Si is precipitated in a Cu matrix, and a specific amount of Sn, Mg, or Zn is added.
O content is limited and the grain size exceeds 25
When the thickness is not more than μm, there is an effect that a copper alloy having excellent mechanical properties, conductivity, stress relaxation properties and bending workability can be obtained. In particular, for terminals and connectors, they are excellent in strength, conductivity, stress relaxation characteristics, bending formability, and Sn plating heat resistance and punching properties. Applicable to performance improvement. In addition, the present invention
Although it is suitable for connector applications, it also has the effect of providing a copper alloy that is also suitable as a general conductive material, such as switches and relay materials.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a stress relaxation test according to an embodiment of the present invention.

[Explanation of symbols]

 1 sample 2 base 3 holding member 4 block

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C22F 1/00 661 C22F 1/00 661A 685 685Z 686 686A 686B 691 691B 694 694A (72) Inventor Yoshimasa Oyama Marunouchi, Chiyoda-ku, Tokyo 2-6-1, Furukawa Electric Co., Ltd.

Claims (10)

[Claims] 1. Ni is 1.0 to 3.5 wt.
%, 0.2-0.9 wt% of Si, 0.01-% of Mg
0.20 wt%, Sn containing 0.05-1.5 wt%,
A copper alloy for a conductive spring, wherein the S and O contents are each limited to less than 0.005 wt%, the balance being Cu and unavoidable impurities, and having a crystal grain size of more than 1 μm and 25 μm or less. 2. Ni is 1.0 to 3.5 wt.
%, 0.2-0.9 wt% of Si, 0.01-% of Mg
0.20 wt%, 0.05 to 1.5 wt% Sn, Zn
, The content of S and O is limited to less than 0.005% by weight, and the balance consists of Cu and unavoidable impurities, and the crystal grain size exceeds 1 μm and 25 μm.
A copper alloy for a conductive spring, comprising: 3. The copper alloy according to claim 1, further comprising 0.005 to 0.3 wt% Ag, 0.01 to 0.5 w.
t% Mn, 0.005 to 0.2 wt% Fe,
Cr, 0.05 to 2.0 wt% Co, 0.005 to 0.
A copper alloy for a conductive spring, comprising one or more selected from 1 wt% P in a total amount of 0.005 wt% to 2.0 wt%. 4. The copper alloy according to claim 1 or 2, further comprising 0.005 to 0.1 wt% Pb, 0.005 to 0.0 wt% Pb.
One or two kinds of 3 wtBi in a total amount of 0.005 to 0.
A copper alloy for conductive springs, comprising 13 wt%. 5. The copper alloy according to claim 1, further comprising 0.005 to 0.3 wt% Ag, 0.01 to 0.5 w.
t% Mn, 0.005 to 0.2 wt% Fe,
Cr, 0.05 to 2.0 wt% Co, 0.005 to 0.
One or more selected from 1 wt% P, and 0.005 to 0.1 wt% Pb, 0.005 to 0.03
One or two types of wtBi in a total amount of 0.005 wt% or more
A copper alloy for a conductive spring, comprising 2.0 wt%. 6. The method according to claim 1, wherein the material is used for any one of a terminal, a connector material, and a switch material.
6. The copper alloy for a conductive spring according to any one of items 1 to 5. 7. A recrystallization treatment after cold working is performed in a range of 700 to 92.
The method for producing a conductive spring copper alloy according to any one of claims 1 to 6, wherein the method is performed at 0 ° C. 8. After cold working, a recrystallization treatment is carried out at 700 to 92.
The method for producing a conductive spring copper alloy according to any one of claims 1 to 6, wherein the aging treatment is performed at 420 to 550 ° C after performing at 0 ° C. 9. After cold working, recrystallization treatment is carried out at 700 to 92.
The copper alloy for a conductive spring according to any one of claims 1 to 6, wherein the copper alloy for a conductive spring is subjected to an aging treatment at 420 to 550 ° C after performing a cold working of 25% or less at 0 ° C. Production method. 10. A recrystallization treatment after cold working is performed in a range of 700 to 9
Perform at 20 ° C., then cold work up to 25%, 420-5
The method for producing a copper alloy for a conductive spring according to any one of claims 1 to 6, wherein after performing the aging treatment at 50 ° C, cold working and low temperature annealing of 25% or less are further performed. .