JP3510469B2 - Copper alloy for conductive spring and method for producing the same - Google Patents

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 conductive springs and a method for manufacturing the same, and more particularly to a terminal / connector material,
TECHNICAL FIELD The present invention relates to a copper alloy for a conductive spring 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 alloys, Cu--Fe alloys and Cu--Sn alloys having excellent heat resistance 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 miniaturized and may be exposed to a harsh environment such as in an engine room. Cu-Z because there are many
Not to mention n-based alloys, Cu-Fe-based alloys, Cu
The current situation is that even Sn-based alloys are no longer available.

As described above, the characteristics required for materials for terminals and connectors have become more severe as the environment in which they are used changes. Copper alloys used for such applications have various properties such as stress relaxation characteristics, mechanical strength, thermal conductivity, bending workability, heat resistance, Sn plating connection reliability, and migration characteristics. Mechanical strength, stress relaxation characteristics, thermal / electrical conductivity, and bendability are important characteristics.

As a copper-based material satisfying these strict requirements, a Cu-Ni-Si-based alloy is drawing attention, and for example, Japanese Patent Laid-Open No. 61-127842 is known. However, even such a Cu—Ni—Si alloy has fallen into a state where it cannot be used. Specifically, when the size of a component is reduced, for example, in a general box-shaped terminal, when the tab width of the male terminal to be inserted is reduced from 090 terminal which is about 2 mm to 040 terminal which is about 1 mm, the spring portion of the spring portion is The width is about 1 mm, and it is difficult to obtain sufficient connection strength when the components are downsized in this way. Also, in order to secure the connection strength in the spring part in connection with the miniaturization, many improvements have been made to the structure of the terminal, but as a result, the bending workability required for the material becomes more severe. However, in the conventional Cu-Ni-Si, cracks often occur in the bent portion. The stress relaxation property is also the same, and it is impossible to use the conventional Cu-Ni-Si alloy for a long time due to an increase in stress applied to the material and an increase in operating environment.

Under these circumstances, it is effective to add Mg in order to improve, for example, stress relaxation characteristics. For example, JP-A 61-250134 and JP-A 5-59468 are also effective in adding Mg. Sex is shown. However, the addition of Mg improves the stress relaxation property, but the bending workability deteriorates, and it cannot withstand 180 ° contact bending. Therefore, it is indispensable to improve the bending workability for use in automobile connectors and the like. Further, studies have been conducted to improve bending workability, but since this is a material having low strength, desired properties cannot be obtained. Further, if the thermal / electrical conductivity is poor, even if the stress relaxation characteristic is good, the stress relaxation is promoted by self-heating, so that the balance between the conductivity and the stress relaxation characteristic is important.

[0006]

As described above, bending workability, stress relaxation characteristics, etc. have been investigated and copper-based materials satisfying strict required characteristics have been proposed. However, the present invention has excellent mechanical characteristics. The present invention provides a copper alloy having both conductivity, stress relaxation characteristics and bending workability, which is suitable for terminals and connectors.

[0007]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems, in which Ni as the main component is 1.0 to 3.5 ma.
ss% , Si 0.2-0.9 mass% , Mg 0.
01 to 0.20 mass% , Sn 0.05 to 1.5 m
including ass% and S and O contents of 0.005 ma each
The strength, the conductivity and the stress relaxation property are not limited to less than ss% , and the balance is Cu and unavoidable impurities, and the grain size is more than 1 μm and 25 μm or less.
And the inner bending radius is 0R.
It is a copper alloy for conductive springs that does not produce racks and has excellent bendability . Further, in the above-mentioned constitution, other additive elements, for example, 0.2%, are added within a range not adversely affecting the characteristics of the present invention.
There is no problem even if less than Zn is added. Further, in the present invention, Ni as a main component is 1.0 to 3.5 ma.
ss% , Si 0.2-0.9 mass% , Mg 0.
01 mass% or more and less than 0.20 mass% , Sn 0.05 to 1.5 mass% , Zn 0.2 to 1.5 m
including ass% and S and O contents of 0.005 ma each
The strength, the conductivity and the stress relaxation property are not limited to less than ss% , and the balance is Cu and unavoidable impurities, and the grain size is more than 1 μm and 25 μm or less.
And the inner bending radius is 0R.
It is a copper alloy for conductive springs that does not produce racks and has excellent bendability .

The present invention further comprises, in addition to the above copper alloy, one or more selected from Ag, Mn, Fe, Cr, Co and P in a total amount of 0.005 mass% to 2.0.
It is a copper alloy characterized by containing mass% . Specifically, Ni as the main component is 1.0 to 3.5 mass% ,
Si is 0.2 to 0.9 mass% , Mg is 0.01 to
0.20 mass% , Sn 0.05 to 1.5 mass
% , And further 0.005-0.3 mass% Ag,
0.01-0.5 mass% Mn, 0.005 each
~ 0.2 mass% Fe, Cr, 0.05-2.0 m
ass% Co, 0.005 to 0.1 mass% P, and one or more kinds selected from the total amount of 0.005 mas
s% to 2.0 mass% , S and O contents are limited to less than 0.005 mass% each, the balance Cu and inevitable impurities, and the crystal grain size exceeds 1 μm 25
strength, conductivity and response characterized by being less than μm
180 ° close contact with force relaxation characteristics and inner bending radius of 0R
It is a copper alloy for conductive springs, which is excellent in bending workability and does not cause cracks in bending . Further, as the main component, Ni is 1.0 to 3.5 mass% and Si is 0.2 to 0.9 ma.
ss% , Mg 0.01 to 0.20 mass% , Sn 0.05 to 1.5 mass% , Zn 0.2 to 1.5 m
including ass% , and further 0.005-0.3 mass% A
g, 0.01 to 0.5 mass% Mn, 0.0 each
05-0.2 mass% Fe, Cr, 0.05-2.
0 mass% Co, 0.005-0.1 mass% P selected from the group of 1 or 2 or more in a total amount of 0.005 m
It is characterized by containing ass% to 2.0 mass% , limiting the S and O contents to less than 0.005 mass% each, the balance Cu and unavoidable impurities, and having a crystal grain size of more than 1 μm and 25 μm or less. Strength, conductivity and
And stress relaxation characteristics, and 180 ° with inner bending radius of 0R
Excellent bending workability that does not cause cracks in tight bending
And a conductive spring copper alloy.

In the present invention, the above copper alloy is further added with one or two of Pb and Bi in a total amount of 0.005 to 0.
It is a copper alloy containing 13 mass% . Specifically, Ni as the main component is 1.0 to 3.5 mass.
% , Si 0.2 to 0.9 mass% , Mg 0.01
~0.20 mass%, the Sn 0.05~1.5 mas
s% included, and 0.005 to 0.1 mass% Pb,
0.005 to 0.03 mass% Bi of 1 type or 2 types is contained in a total amount of 0.005 to 0.13 mass% , S, O
Each content is limited to less than 0.005 mass% ,
A strong characteristic that the balance consists of Cu and unavoidable impurities, and the crystal grain size is more than 1 μm and 25 μm or less.
Degree, conductivity and stress relaxation characteristics, and inner bend radius
A curve that does not cause cracks in 0 ° 180 ° close contact bending
It is a copper alloy for conductive springs that has excellent buffing workability . Further, as main components, Ni is 1.0 to 3.5 mass% , Si is 0.2 to 0.9 mass% , and Mg is 0.01 to 0.20.
mass% , Sn 0.05 to 1.5 mass% , Zn
0.2 to 1.5 mass% , and further 0.005
0.1 mass% Pb, 0.005-0.03 mass
% Bi in a total amount of 0.005 to 0.13
mass% and S and O contents of 0.005 m each
strength, conductivity and stress relaxation characteristics, characterized in that the crystal grain size is more than 1 μm and 25 μm or less, with the balance being Cu and unavoidable impurities, the content of which is limited to less than ass% .
And 180 ° contact bending with an inner bending radius of 0R
This is a copper alloy for conductive springs that does not cause cracks and has excellent bendability .

In addition to the above copper alloy, Ag, M
1 or 2 selected from n, Fe, Cr, Co and P
Or more, and one or two of Pb and Bi in a total amount of 0.
It is a copper alloy characterized by containing 005 mass% to 2.0 mass% . Specifically, Ni is 1.0 to 3.5 mass% and Si is 0.2 to 0.9 ma as main components.
ss%, a Mg 0.01 to 0.20 mass%, wherein the Sn 0.05 to 1.5 mass%, further 0.005
0.3 mass% Ag, 0.01 to 0.5 mass% M
n, 0.005-0.2 mass% of Fe and C, respectively
r, 0.05 to 2.0 mass% Co, 0.005
One or two or more selected from 0.1 mass% P, and 0.005 to 0.1 mass% Pb, 0.00
5 to 0.03 mass% Bi of 1 type or 2 types in a total amount of 0.005 mass% to 2.0 mass% is contained, and S, O
Each content is limited to less than 0.005 mass% ,
A strong characteristic that the balance consists of Cu and unavoidable impurities, and the crystal grain size is more than 1 μm and 25 μm or less.
Degree, conductivity and stress relaxation characteristics, and inner bend radius
A curve that does not cause cracks in 0 ° 180 ° close contact bending
It is a copper alloy for conductive springs that has excellent buffing workability . Further, as main components, Ni is 1.0 to 3.5 mass% , Si is 0.2 to 0.9 mass% , and Mg is 0.01 to 0.20.
mass% , Sn 0.05 to 1.5 mass% , Zn
0.2 to 1.5 mass% , and further 0.005
0.3 mass% Ag, 0.01 to 0.5 mass% M
n, 0.005-0.2 mass% of Fe and C, respectively
r, 0.05 to 2.0 mass% Co, 0.005
One or two or more selected from 0.1 mass% P, and 0.005 to 0.1 mass% Pb, 0.00
5 to 0.03 mass% Bi of 1 type or 2 types in a total amount of 0.005 mass% to 2.0 mass% is contained, and S, O
Each content is limited to less than 0.005 mass% ,
A strong characteristic that the balance consists of Cu and unavoidable impurities, and the crystal grain size is more than 1 μm and 25 μm or less.
Degree, conductivity and stress relaxation characteristics, and inner bend radius
A curve that does not cause cracks in 0 ° 180 ° close contact bending
It is a copper alloy for conductive springs that has excellent buffing workability .

The copper alloy of the present invention is characterized in that it 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, which comprises performing recrystallization treatment at 700 to 920 ° C. after cold working. Also,
A method for producing a copper alloy for a conductive spring, which comprises performing recrystallization treatment at 700 to 920 ° C. after cold working and then performing aging treatment at 420 to 550 ° C. Further, recrystallization after cold working The treatment is carried out at 700 to 920 ° C. for another 25
% Of cold working, and then aging treatment at 420 to 550 ° C. is a method for producing a copper alloy for a conductive spring. Furthermore, after cold working, recrystallization treatment is performed 70 times.
Perform at 0-920 ° C, then cold work up to 25%, 42
25% after aging treatment at 0-550 ° C
The method for producing a copper alloy for a conductive spring is characterized by performing the following cold working and low temperature annealing.

[0012]

The copper alloy of the present invention has a Ni matrix in a Cu matrix.
And a compound of Si are deposited to obtain appropriate mechanical strength and heat.
A specific amount of Sn, Mg, and Zn is added to a copper alloy having electrical conductivity, the S and O contents are limited, and the grain size is 1
The main idea is to improve the stress relaxation characteristics and bending workability by making the thickness more than 25 μm and less than 25 μm. The present inventors realize a copper alloy for conductive springs having practically excellent properties, particularly a material having excellent properties for terminals and connectors, by defining the content of the copper alloy component in detail. It was found that the copper alloy of the present invention was obtained as a result.

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 and this is precipitated in Cu to improve strength and conductivity. If the Ni content is less than 1.0 mass% , the amount of precipitation is small and the target strength cannot be obtained.
On the other hand, if the Ni content exceeds 3.5 mass% , precipitation that does not contribute to the increase in strength occurs during casting and hot working, and not only the strength commensurate with the content cannot be obtained, but also the hot workability and bending workability. It will have an adverse effect. The amount of Si is considered to be the compound of precipitated Ni and Si in the Ni2Si phase. Therefore, determining the amount of Ni determines the optimum Si content. If the Si content is less than 0.2 mass% , sufficient strength cannot be obtained as in the case where the Ni content is small. On the contrary, when the Si content exceeds 0.9 mass% , the same problem occurs as when the Ni content is large. Preferably, Ni is 1.7 to 2.8 mass% and Si is 0.4 to 0.7 ma.
It is desirable to adjust to ss% .

Mg and Sn are important additive elements constituting the copper alloy of the present invention. These elements are related to each other to achieve a good property balance. Next, the reasons for limiting these elements will be described. Mg significantly improves the stress relaxation property, but adversely affects the bending workability. From the viewpoint of stress relaxation characteristics, the content is preferably as high as 0.01 mass% or more. On the contrary, from the viewpoint of bending workability, if the content exceeds 0.20 mass% , it is difficult to obtain good bending workability. From such a viewpoint, the Mg content shows a good balance in the range of 0.01 to 0.20 mass% . A more preferable Mg content range from the viewpoint of bending workability is 0.01 to 0.1 mass% .

Further, it was 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, its effect is not as great as that of Mg.
It has a good characteristic balance by being interrelated with g. When Sn is contained in an amount of more than 1.5 mass% ,
The thermal and electrical conductivity deteriorates, causing practical problems. S
Although the n content has a trade-off with the Mg content, it is 0.05 to
A good property balance is exhibited at 1.5 mass% . More specifically, when Mg is 0.01 to 0.05 mass% is, Sn is preferably 0.8 to 1.5 mass%, Mg
When the amount is 0.05 to 0.1 mass% , Sn is preferably 0.05 to 0.8 mass% .

Zn does not contribute to stress relaxation characteristics, but can improve bending workability. 0.2 to 1.5 for Zn
By containing the mass% , preferably 0.3 to 1.0 mass% , it is possible to achieve a bending workability of a level practically no problem even if Mg is contained up to 0.20 mass% at the maximum. Further, Zn has the effect of improving the heat-resistant peeling property of Sn plating or solder plating and the migration property, and also has the effect of improving the punching workability.
It is desirable that n is contained in an amount of 0.2 mass% , preferably 0.3 mass% or more. Elements that improve punching workability include Pb and Bi. If Pb and Bi are added in a large amount, hot workability is impaired, but Zn does not adversely affect productivity and improves punching workability. Since it is possible, it is an effective additive element. Its upper limit considering the conductive heat and electrical, 1.5 mass%, preferably 1.0 mas
s% . It should be noted that this example also shows that co-addition with Mg has a better tendency.

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

Next, Ag, Mn, Fe, Cr, Co, P
The reason for limiting the content range of will be described. Ag, M
n, Fe, Cr, Co and P have similar functions in terms of improving workability, and Ag, Mn,
One or two or more selected from Fe, Cr, Co and P are contained in an amount of 0.005 mass% to 2.0 mass% .

Ag increases heat resistance and strength, and at the same time prevents coarsening of crystal grains and improves bending workability. Conventionally, it has been attempted to add various third elements in order to increase the strength of Cu-Ni-Si alloys, but they significantly reduce the electrical conductivity and the bend formability. It deteriorated and exhibited properties unfavorable for use in electronic devices. The present invention is
As a result of repeated examination of elements that improve strength and do not adversely affect other properties, it was found that Ag is effective. Content is 0.005 mass%
If it is less than 0.3 % , the effect does not appear, and conversely 0.3 mass%
If it is contained in excess, there is no adverse effect on the characteristics, but the cost increases, so the optimum content of Ag is 0.005-0.3.
mass% , and more preferably 0.005 to 0.1
mass% .

Mn has the effect of increasing the strength and at the same time improving the hot workability. If it is less than 0.01 mass% , the effect is small, and if it exceeds 0.5 mass% , Not only the effect commensurate with the content cannot be obtained, but also the conductivity is deteriorated. Therefore, the optimal content range of Mn is 0.01 to 0.5 mass% , and more preferably 0.03 to 0.3 mass% .

Fe and Cr are combined with Si to form Fe--Si.
A compound and a Cr-Si compound are formed to increase the strength.
It also has the effect of trapping Si remaining in the copper matrix without forming a compound with Ni, and improving the conductivity. Since Fe-Si compounds and Cr-Si compounds have low precipitation hardening ability, it is not a good idea to produce many compounds. Further, if the content exceeds 0.2 mass% , bending workability deteriorates. From these viewpoints, when Fe and Cr are contained, the addition amount is 0.005 to 0.2 mass.
% , And more preferably 0.005 to 0.1 mass
% .

Co, like Ni, forms a compound with Si and improves the mechanical strength. Since Co is more expensive than Ni, a Cu—Ni—Si alloy is used in the present invention, but if cost permits, Cu—C is used.
You may select o-Si type | system | group or Cu-Ni-Co-Si type | system | group. The Cu-Co-Si system is Cu when it is aged and precipitated.
Both mechanical strength and conductivity are slightly better than those of the Ni-Si system. Therefore, it is effective for members in which heat and electricity conductivity are important. Further, since the Co—Si compound has a slightly high precipitation hardening ability, the stress relaxation property tends to be slightly improved. From these points of view, the optimum amount of addition of Co is 0.05 to 2.0 mass% .

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

Next, the reason why the range of Pb and Bi contents is limited will be described. Pb and Bi improve punching workability, and Pb and Bi are 0.001% or less.
5 to 0.13 mass% is contained. Pb is an additive element that improves punching workability. With the recent increase in press speed, terminal materials are required to have better workability. Pb is dispersed in the copper matrix and becomes the starting point of fracture, improving the punching workability. If the amount of Pb is less than 0.005 mass% , there is no property improving effect, and if it is added in excess of 0.1 mass% , not only the hot workability is deteriorated, but also the bendability is deteriorated. from 005 to .1 mass% is optimal, and more preferably from 0.005 to 0.05 mass%. B
i is also an additional element that improves punching workability. 0.0
If it is less than 05 mass% , the effect of improving the characteristics is small,
If it is added in excess of 0.03 mass% , the same characteristic deterioration as Pb will occur. Therefore, the optimum Bi content range is 0.00
5 to 0.03 mass% , more preferably 0.0
It is 05 to 0.02 mass% .

These Ag, Mn, Fe, Cr, Co and P
In the case of simultaneously containing one or more selected from the above, and one or two of Pb and Bi at the same time, the heat resistance, Sn plating, and solder may be appropriately determined according to the required characteristics. The total amount was 0.005 to 2.0 mass% from the viewpoints of plating heat resistance peeling property and conductivity.

Next, the S and O contents are set to 0.005 mass.
Explain the reason why it is limited to less than % . Usually, industrial copper materials contain a small amount of S, O _2, etc., but the present invention has excellent characteristics in combination with the alloy components described above and the grain size regulation described later by strictly limiting the contents thereof. It is intended to realize. S is an element that deteriorates hot workability, and improves the hot workability by defining its content to be less than 0.005 mass% . In particular, the S content should be 0.
It is desirable to set it to less than 002 mass% . When the content of O is 0.005 mass% or more, Mg is oxidized and bending workability deteriorates. O content 0.00
It is preferably 5 mass% or less, and particularly preferably less than 0.002 mass% . Although S and O described above are often contained in a small amount in ordinary copper-based materials, they are particularly important in the copper alloy of the present invention, and by defining their contents, excellent characteristics can be obtained. Therefore, they have found that they have suitable characteristics for materials for terminals and connectors.

In the above-mentioned composition of the copper alloy of the present invention,
In order to realize those characteristics properly, the crystal grain size is 1 μm
Over 25 μm or less. When the grain size is 1 μm or less, mixed grains are likely to be formed in the recrystallized structure, bending workability is deteriorated, and at the same time, stress relaxation property is deteriorated. Conversely, even if the grain size grows beyond 25 μm,
Bendability is adversely affected. Therefore, the grain size is 1μ
It is necessary to adjust to exceed 25 m and less than m.

Next, the method for producing the copper alloy of the present invention will be described. The copper alloy of the present invention is cold-worked, for example, cold-rolled, then heat-treated for the purpose of recrystallization and solution treatment, and immediately quenched. In addition, aging treatment is performed as necessary. 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 process in detail. 700
Heat treatment at a temperature below ℃ tends to cause mixed grains,
Since the crystal grains are likely to grow coarsely at a temperature exceeding 1, the recrystallization treatment is performed at 700 to 920 ° C. after the cold working. Also, the cooling rate is as fast as possible, 10 ℃ / s
It is desirable to cool at the above rate.

Next, as for the condition of the aging heat treatment, if the aging temperature is less than 420 ° C., the amount of precipitation hardening is insufficient and sufficient characteristics cannot be obtained. On the contrary, 550
When treated at a temperature above ℃, the precipitate phase grows coarsely,
Not only the strength is lowered, but also the stress relaxation property is lowered. Therefore, the aging treatment temperature was set to 420 to 550 ° C. Furthermore, it has been known that the stress relaxation characteristics are greatly affected by the state of the precipitation phase, and the best condition is near the temperature at which the aging strength shows a peak. On the other hand, regarding bending workability, it is desirable that the heat treatment is performed slightly on the overaging side from the temperature at which the aging strength shows a peak. From this viewpoint, it is preferably 46
The treatment at 0 to 530 ° C is optimal.

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

[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 peelability,
It has punching properties and the like, and in particular, has properties required for general conductive materials such as terminal / connector materials, switch materials, relay materials, etc., which 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 1-6. Table 1 shows the alloy composition of the present invention, Tables 2 and 3 show the alloy compositions of the comparative examples and the conventional example, Table 4 shows the characteristics of the inventive alloy, and Tables 5 and 6 show the alloys of the comparative example and the conventional example. It shows the characteristics of. The arrows in the table indicate the same as 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 ingot has a thickness of 30 mm, a width of 100 mm, and a length of 15
It is 0 mm. Next, these ingots were hot-rolled at 900 ° C. and then rapidly cooled. In order to remove the oxide film on the surface, the surface was ground to a thickness of 9 mm, and then cold rolled to a thickness of 0.25 mm. Then, for the purpose of recrystallizing and solutionizing the test material, heat treatment was performed at 750 ° C. for 30 s, and immediately quenching was performed at a cooling rate of 15 ° C./s or more. As the aging treatment, a heat treatment was performed at 515 ° C. for 2 hours in an inert atmosphere to obtain a material to be tested.

Sampling is performed from the manufactured material, and the grain size is measured. 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, fracture surface ratio (%) as punching property, and burr (μm) were evaluated.

The crystal grain size, that is, the size of the crystal grain is determined according to JIS
According to H0501, observation was carried out using both the comparative method and the cutting method. In the comparative method, the test piece was observed under a microscope (75 times or 20 times).
(0 times) and measured. In the cutting method, measurement was performed on a plate thickness cross section parallel to the processing direction. Tensile strength is JISZ2241
The electrical conductivity is defined by JIS as a value showing the conductivity of heat and electricity.
It measured according to H0505.

The bending workability was evaluated by determining that the inner bending radius was OR.
180 degree contact bending was performed. The evaluation index is A. No wrinkles and good. Small wrinkles are observed C. Large wrinkles are observed, but cracks have not been reached. E. In which fine cracks are observed The crack was clearly observed and evaluated on a scale of 5 and a rating of C or higher was judged to be a level having no practical problem.

The stress relaxation characteristics were evaluated in accordance with EMAS-3003, which is a standard of the Japan Electronic Material Industry Association. Here, the cantilever block type is adopted, and the load stress is set so that the maximum surface stress is 450 N / mm ^2.
The test was conducted in a constant temperature bath at 0 ° C. Tables 4 to 6 show 100
The relaxation rate (SR) after the 0 hr test is shown.

The cantilever block method of the stress relaxation test method is shown in FIGS. 1 (a), 1 (b) and 1 (c). 1A is a perspective view and FIG. 1B is a side view. One of the samples (1) is supported by a holding member (3) on a base (2) in a cantilevered state,
On the other hand, the sample (1) is given a strain δo (initial flexural 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. 1 (c)
Strain δt (permanent flexural displacement) was measured with the block (4) removed, and the stress relaxation rate (%) was calculated by the following equation. Stress relaxation rate (%) = (δt / δo) × 100 In the initial flexural displacement, the maximum surface stress is a predetermined value (4
It is calculated from Young's modulus, plate thickness, etc. so as to be 50 N / mm ² ) (the calculation method is according to EMAS-3003).

The heat releasability of the Sn plating was obtained by heating a test piece plated with 1 μm of bright Sn plating at 150 ° C. for 1000 hours in the atmosphere, bending it 180 degrees, and then bending it back. The peeling of the plating was visually evaluated. When the peeling of the solder was observed, it was described as “Yes” in Tables 4 to 6.

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

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

As is clear from Table 4, the invention examples 1-2
1 is TS (tensile strength), El (elongation), EC (conductivity), bending workability, S.I. R. It can be seen that all of various characteristics such as R (stress relaxation rate), Sn plating releasability, and punchability exhibit excellent characteristics.

On the other hand, Comparative Example No. 1 having a small amount of Ni-Si.
No. 22 does not have the desired strength and is inferior in punching workability to other materials. On the contrary, Comparative Example No. 1 having a large amount of Ni-Si. No. 23 of the present invention has a small amount of Ni-Si. Although there was no difference in strength as compared with No. 4, there was a tendency for deterioration in bending workability. That is, adding Ni-Si in an amount not less than the amount specified in the present invention is inferior in bending workability, and is not suitable for terminals and connectors.

Comparative Example No. 1 containing a small amount of Mg. 24
No. of the present invention example. 2, No. Compared with No. 5, the stress relaxation characteristics are significantly inferior. For the same reason, Comparative Example N
o. No. 25 of the present invention example. 6, No. Inferior to 7. This shows that even if Sn alone is 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. It matches the characteristic of 43).

Comparative Example No. 3 in which the added amount of Mg was more than the specified amount of the present invention. No. 26 has deteriorated bending workability. This is unsuitable as a terminal / connector material. Even if Zn was added in an amount of 1 mass% or more, which can slightly improve the bending workability, good bending workability could not be secured. Comparative example No. with a small addition amount of Sn. No. 27 of the example of the present invention. 2 is inferior to that of No. 2 in stress relaxation characteristics. On the contrary, the comparative example No. 1 containing a large amount of Sn. No. 28 was one of the compositions that showed the most excellent stress relaxation property in the production this time in combination with the effect of Mg. However, it has the lowest conductivity, and cannot be said to be excellent in balance. Comparative Example No. 1 in which the amount of Zn added was large. No. 29 also has a low electric conductivity and is not excellent in property balance.

Comparative Example N in which the added amount of Fe is more than the specified amount
o. In No. 30, not only the Fe—Si compound was produced in a large amount, the precipitation hardening amount was lowered, but also the bending workability was adversely affected. Comparative example No. 1 in which the amount of Pb added was increased. No. 31 was cracked during hot working and could not be manufactured normally. In addition, Comparative Example No. S in which S is outside the scope of the present invention.
In No. 32, cracking occurred during hot working, and subsequent characteristic evaluation could not be performed. In addition, Comparative Example No. 1 containing a large amount of O. 33 is M
Since the oxide of g was generated, the bending workability was deteriorated.

Comparative Example No. In No. 34, annealing for recrystallization was performed at 680 ° C. for 30 seconds. As a result, the average crystal grain was 1 μm or less, and the structure was such that relatively large crystal grains and small crystal grains were mixed. Due to the non-uniform structure, cracks were generated depending on the place where the bending test piece was sampled. On the contrary, Comparative Example No. 35 is 93
Since the heat treatment was performed at 0 ° C for 30 s, the crystal grains were about 3
It became 0 μm. The coarse crystal grains not only adversely affect the bending workability but also slightly deteriorate the stress relaxation characteristics.

Comparative Example No. 36-No. 41 is C
This is a comparative example in which an element other than Sn is added to the u-Ni-Si-Mg-Zn alloy. The stress relaxation characteristics of all of these alloys are those of Comparative Example No. 1 in which the addition amount of Sn is small. The stress relaxation characteristics are similar to those of No. 27, and it can be seen that the addition of these elements hardly contributes to stress relaxation.

Next, looking at conventional alloys, the conventional example No. 42 is a Cu-Ni-Si alloy, and does not contain other additive elements. In this case, since the stress relaxation property is not good and Zn is not contained, Sn
There is a problem with the heat releasability of the plating. Conventional example No. As described above, 43 is a material in which Sn and Zn are added to the Cu-Ni-Si based alloy. Although the heat releasability of the Sn plating is improved, the stress relaxation characteristics of the conventional example No. It is equivalent to 41 and is insufficient.

No. 44 is a material in which Mg is added to improve the stress relaxation characteristic. 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 stress relaxation characteristics equivalent to those of No. 44 and good bending workability, the invention sample No. Like 2,
This is achieved by reducing the amount of Mg, adding Sn, and further adding Zn that improves bending workability. The effect of adding Zn also improves the heat peelability of Sn plating.

[0050]

[Embodiment 2] A second embodiment of the present invention will be described with reference to Tables 7 and 8. The second example is the same as Example No. 1 of the present invention shown in the first example. An alloy having the composition of No. 2 was manufactured by the process 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 releasability, and F. A. R (%), burr (μ
Various characteristics of m) were evaluated. The evaluation method is the same as in Example 1.

[Table 7]

[Table 8]

As is apparent from Tables 7 and 8, the invention example No. 1 which is an alloy produced in the steps of the invention example. 45-N
o. All of 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 bending workability deteriorated. Comparative Example No.
Since No. 55 was heat-treated at 930 ° C. × 30 s, the crystal grain became about 30 μm. The coarse crystal grains not only adversely affect bending workability, but also slightly deteriorated stress relaxation characteristics.

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

[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 Sn, Mg, or Zn is added in a specific amount, and S,
O content is limited and the grain size exceeds 1 μm 25
When the thickness is less than or equal to μm, a copper alloy having excellent mechanical characteristics, conductivity, stress relaxation characteristics, and bending workability can be obtained. In particular, for terminals and connectors, it is excellent in strength, conductivity, stress relaxation characteristics, bend formability, and also has excellent heat peeling resistance and punching resistance for Sn plating. Suitable for performance improvement. In addition, the present invention is
Although it is suitable for use in connectors, it also has the effect of providing a copper alloy suitable for general conductive materials such as switches and relay materials.

[Brief description of 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 bases 3 holding member 4 blocks

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C22F 1/00 661 C22F 1/00 661A 685 685Z 686 686A 686B 691 691B 694 694A (72) Inventor Yoshiyama Omasa Marunouchi, Chiyoda-ku, Tokyo 2-6-1, Furukawa Electric Co., Ltd. (56) Reference JP-A-3-188247 (JP, A) JP-A-5-59468 (JP, A) (58) Fields investigated (Int.Cl . ⁷ , DB name) C22C 9/00 C22F 1/00-3/02 H01B 1/02

Claims (11)

(57) [Claims] 1. Ni as the main component is 1.0 to 3.5 ma.
ss% , Si 0.2-0.9 mass% , Mg 0.
01 to 0.20 mass% , Sn 0.05 to 1.5 m
including ass% and S and O contents of 0.005 ma each
The strength, the conductivity and the stress relaxation property are not limited to less than ss% , and the balance is Cu and unavoidable impurities, and the grain size is more than 1 μm and 25 μm or less.
And the inner bending radius is 0R.
A copper alloy for conductive springs that does not cause racks and has excellent bending workability (however, Ni is 1.6 mass% and Si is 0.4 m).
ass%, Sn 0.5 mass%, Mg 0.2 ma
(Excluding those containing 0.01% by mass of ss% and P) . 2. Ni as the main component is 1.0 to 3.5 ma.
ss%, Si 0.2 to 0.9 mass%, Mg 0.
01 mass% or more and less than 0.20 mass%, Sn
0.05 ~ 1.5mass%, S, O content
Each is limited to less than 0.005 mass% and the balance Cu and
Consists of unavoidable impurities and its grain size exceeds 1 μm
25 μm or less, strength, conductivity and
And stress relaxation characteristics, and 180 ° with inner bending radius of 0R
Excellent bending workability that does not cause cracks in tight bending
Copper alloy for conductive springs. 3. Ni as the main component is 1.0 to 3.5 ma.
ss% , Si 0.2-0.9 mass% , Mg 0.
01 mass% or more and less than 0.20 mass% , Sn 0.05 to 1.5 mass% , Zn 0.2 to 1.5 m
including ass% and S and O contents of 0.005 ma each
The strength, the conductivity and the stress relaxation property are not limited to less than ss% , and the balance is Cu and unavoidable impurities, and the grain size is more than 1 μm and 25 μm or less.
And the inner bending radius is 0R.
Copper alloy for conductive springs that does not produce racks and has excellent bendability . 4. A copper alloy according to any one of claims 1-3, further 0.005 to 0.3 mass% Ag,
0.01-0.5 mass% Mn, 0.005 each
~ 0.2 mass% Fe, Cr, 0.05-2.0 m
ass% Co, 0.005 ma with one or total of two or more selected from among 0.005 to 0.1 mass% P
A copper alloy for conductive springs, characterized by containing ss% to 2.0 mass% . 5. A copper alloy according to any one of claims 1-3, further 0.005 to 0.1 mass% Pb,
0.005-0.03 mass% Bi 1 type or 2 types are contained in 0.005-0.13 mass% in total amount, The copper alloy for electroconductive springs characterized by the above-mentioned. 6. A copper alloy according to any one of claims 1-3, further 0.005 to 0.3 mass% Ag,
0.01-0.5 mass% Mn, 0.005 each
~ 0.2 mass% Fe, Cr, 0.05-2.0 m
ass% Co, 1 kind or 2 or more selected from among 0.005 to 0.1 mass% P, and 0.005 to 0.
1 mass% Pb, 0.005-0.03 mass% B
The total amount of 1 type or 2 types of i is 0.005 mass% -
A copper alloy for conductive springs, which contains 2.0 mass% . 7. The material for use in any of a terminal, a connector material and a switch material.
7. A copper alloy for conductive springs according to any one of 6 to 6 . 8. The recrystallization treatment after cold working is 700 to 92.
It carries out at 0 degreeC, The manufacturing method of the copper alloy for electroconductive springs in any one of the Claims 1 thru | or 7 characterized by the above-mentioned. 9. The recrystallization treatment after cold working is 700 to 92.
The method for producing a copper alloy for a conductive spring according to any one of claims 1 to 7 , wherein the aging treatment is performed at 420 to 550 ° C after the treatment at 0 ° C. 10. The recrystallization treatment after cold working is 700-9.
Carried out at 20 ° C., after carrying out the processing for 25% or less of cold, the copper alloy for the conductive spring according to any one of claims 1 to 7, characterized in that the aging treatment at four hundred and twenty to five hundred fifty ° C. Production method. 11. The recrystallization treatment after cold working is 700 to 9
Performed at 20 ° C, then cold working up to 25%, 420-5
After aging treatment at 50 ° C., 250 to 4 if further cold working at 25% or less and batch annealing.
When performing annealing for 5 to 5 hours at a temperature of 00 ° C during running
The method for producing a copper alloy for a conductive spring according to any one of claims 1 to 7 , wherein annealing is performed at a temperature of 600 to 800 ° C for 5 to 60 seconds .