JP2945208B2 - Method for producing copper alloy for electrical and electronic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a copper alloy for electric and electronic equipment which is suitable for a lead frame material such as a transistor or an integrated circuit (IC), and a spring material such as terminals, connectors, switches and relays. It is.

[0002]

2. Description of the Related Art Materials for electric and electronic devices, for example, semiconductor device materials represented by lead frame materials, and conductive materials represented by springs, connectors, switches and the like for electric devices have conventionally been brass, phosphor bronze, Sn. Copper containing copper, copper containing Fe, and the like have been used. However, with the miniaturization, weight reduction and high density of electric and electronic equipment, a high balance of strength, spring property and conductivity is strongly demanded for these materials, and it is becoming difficult to respond with conventional alloys. Is the current situation. Therefore, Cu-
Ni-Si-based so-called Corson-based copper alloys have been used.

[0003] However, although this Corson-based copper alloy is excellent in the above-mentioned practical properties such as strength, spring property and conductivity, it has not been widely used because it has a remarkable drawback in terms of manufacturability. . That is, in the production of the Corson-based copper alloy, brittle cracks occur due to the action of residual stress during casting solidification in the temperature range of 300 to 600 ° C. during heating for hot rolling, especially in the temperature range of 300 to 600 ° C. This has an adverse effect on rolling and significantly reduces the yield.

In order to obtain good strength and conductivity, the Corson-based copper alloy needs to be subjected to a rapid cooling treatment (solution treatment) after holding at a high temperature. For this purpose, a batch annealing method has conventionally been used. Is adopted, there is a problem that the manufacturing process is complicated and the cost is high. In addition, when the strip is annealed in a coiled state, a bending stress is generated on the surface, and this stress acts in the same manner as the above-mentioned residual stress, so that the above-described brittle crack may occur. Was. In this case, the yield will be significantly reduced by the subsequent cold rolling.

On the other hand, when the solution treatment is performed by quenching after the hot working in the hot working step, the essential recrystallization treatment is not performed in the subsequent annealing, so that the structural anisotropy by the cold working is performed. This causes a problem that ductility such as bending formability is greatly reduced.

[0006] From such a background, there has been a strong demand for the production of Corson-based copper alloys to improve the yield, to reduce the production cost by simplifying the process, and to improve the performance such as formability.

[0007]

SUMMARY OF THE INVENTION The present invention has been made as a result of intensive studies in view of the above points, and its object is
In a method for producing a u-Ni-Si alloy, strength and spring properties are improved by using a continuous annealing method without using a batch method which increases production costs when performing solution annealing while improving hot rolling properties. Another object of the present invention is to provide a method for producing a copper alloy for electric and electronic equipment which is excellent in conductivity and good in bending formability at low cost.

[0008] That is, the present invention provides Ni: 1.0 to 4.0 wt.
%, Si: 0.1 to 1.0 wt%, Zn: 0.1 to 5.0
wt%, Mn: 0.01 to 0.2 wt%, P: 0.01 wt%
Contains the following or further Sn: 0.01 to 3.0 wt%
Is hot-worked at a temperature of 700 ° C. or more, and then the copper alloy containing Cu and the unavoidable impurities is
After quenching at a rate of 0 ° C./sec or more, cold working is performed, continuous annealing with recrystallization is performed at a temperature of 700 ° C. or more, and then quenching is performed at a rate of 10 ° C./sec or more. At 400 to 600 ° C. for 10 minutes to 5 hours, or after this heat treatment, cold working at a working degree of 40% or less, and further annealing at 250 to 500 ° C. for 1 minute to 5 hours. Things.

[0009]

First, the reasons for limiting the alloy composition will be described in detail.

[0010] Ni and Si are both elements that impart strength, spring property, conductivity and the like, and have a Ni content of 1.0 to 4.0.
The reason why the content is limited to 0 wt% is that if the content of Ni is less than 1.0 wt%,
It is difficult to obtain high strength and high conductivity even if the content of Ni is 0.1 wt% or more, and on the other hand, if the content of Ni exceeds 4.0 wt%, the conductivity, bending formability and the like are reduced. .

The reason for limiting the Si content to 0.1 to 1.0 wt% is that if the content of Si is less than 0.1 wt%, the content of Ni is 1.0 to 1.0 wt%.
This is because high strength and high conductivity cannot be obtained even if it is contained in an amount of not less than wt%, and on the other hand, if the content of Si exceeds 1.0 wt%, the conductivity and the solderability are reduced.

Zn is heat-peeling resistance of solder and Sn plating,
The element that improves the migration resistance is limited to 0.1 to 5.0% by weight. The effect is small when the content is less than 0.1% by weight, and when the content is more than 5.0% by weight, the conductivity and the soldering property are reduced. This is because the attachment property is reduced.

Mn is an element for preventing embrittlement during hot working and continuous annealing, and its content is 0.01 to 0.2 wt.
The reason why the amount is limited to 0.1% is that if the content is less than 0.01% by weight, the above effect is small, and if it exceeds 0.2% by weight, the conductivity and the solderability are reduced.

If P is contained in a large amount, it significantly promotes embrittlement during hot working and continuous annealing, and adversely affects subsequent working. Therefore, the content of P must be 0.01 wt% or less.

It has been found that when the addition of an optimum amount of Mn and the control of the P content are performed in combination, hot workability and embrittlement during annealing are significantly improved. Is not controlled to an appropriate amount, the improvement effect is small.

Sn is an element that improves the strength, spring property and bendability, and its content is limited to 0.01 to 3.0% by weight. If the content exceeds 0.0 wt%, conductivity and hot workability are adversely affected.

Next, the reasons for limiting the manufacturing method will be described. The reason why the hot working of the copper alloy ingot having the above composition was terminated at a temperature of 700 ° C. or more, that is, the hot working end temperature was set to 700 ° C. or more, and the subsequent quenching rate was limited to 10 ° C./sec or more If the temperature is less than 700 ° C., the solution is incomplete and precipitation occurs even if quenched at a rate of 10 ° C./sec or more, and adversely affects the solution treatment in the subsequent continuous annealing, so that the strength and the spring property eventually deteriorate. Because you do. Further, embrittlement cracks occur during hot working, which makes subsequent cold working difficult.

The reason why the quenching rate is limited to 10 ° C./sec or more is that if it is less than 10 ° C./sec, precipitation occurs during cooling even if the end temperature of hot working is 700 ° C. or more. This is because good strength and resiliency cannot be finally obtained even if the surface treatment is performed.

Next, the reason why the continuous annealing method is adopted as the annealing method is that the production cost is greatly reduced because the process is simplified by preventing the embrittlement cracking by the batch type annealing.

The reason for limiting the continuous annealing temperature to 700 ° C. or more and the subsequent rapid cooling rate to 10 ° C./sec or more is as follows.
At a temperature of less than 00 ° C., recrystallization does not occur and the final bendability deteriorates significantly. At a temperature of less than 700 ° C. and a cooling rate of less than 10 ° C./sec, the solution is incomplete. This is because precipitation occurs and the final strength and spring property are deteriorated.

That is, in the alloy of the present invention, good characteristics can be achieved at low cost by combining the optimum hot working conditions and the continuous annealing conditions.

Next, cold working is performed at 400 ° C. to 600 ° C.
The reason for annealing for 10 minutes to 5 hours is that the annealing temperature is 400 ° C.
If the temperature is lower than 600 ° C., the precipitation is insufficient. On the other hand, if the temperature exceeds 600 ° C., the precipitates are re-dissolved, so that the strength and conductivity are not improved. Also, if the annealing time is less than 10 minutes, precipitation is insufficient, so that strength and conductivity are not improved. On the other hand, if it exceeds 5 hours, strength and conductivity are hardly changed and energy is wasted. .

The reason for performing cold working at a working ratio of 40% or less after the heat treatment, if necessary, is that if the cold working exceeds 40%, the anisotropy increases, and the bendability decreases significantly. This is because

The reason for performing annealing at 250 ° C. to 500 ° C. for 1 minute to 5 hours is to remove the local stress and improve the resilience. However, if the annealing temperature is lower than 250 ° C., the effect is small. When the temperature exceeds ℃, the strength and the spring property are reduced. If the annealing time is less than 1 minute, the effect is small, and if the annealing time exceeds 5 hours, the effect is not changed, but the energy is wasted. The same effect can be obtained by using either the batch method or the running method as the annealing method.

As described above, according to the present invention, a connector,
Significant reduction in manufacturing cost of Cu-Ni-Si-based copper alloys with excellent hot workability, strength, spring properties, conductivity, and bendability suitable for use in electrical and electronic equipment parts such as lead frames The effect is industrially significant.

[0026]

Next, the present invention will be described in detail with reference to examples.

Example 1 A copper alloy having the composition shown in Table 1 was melted in a high-frequency melting furnace.
An ingot having a thickness of 100 mm, a width of 300 mm, and a length of 1000 mm was produced. Then, these cast materials are heated to a temperature of 850 ° C., and hot-rolled to a thickness of 12 mm.
It was quenched at a cooling rate of ° C./sec. This rolled material is 10mm thick
After cold rolling at a work ratio of 94%, continuous annealing at 850 ° C. was performed, and quenching was performed at a rate of 100 ° C./sec. Subsequently, cold rolling was performed at a working ratio of 40%, and annealing was performed at 460 ° C. for 2 hours. Further, the annealed material is subjected to cold rolling at a working ratio of 20%, and thereafter, is annealed at 400 ° C. for 2 hours to obtain a copper alloy No. 1 to No. 4 of the present invention and a copper alloy No. 5 of a comparative example.
No. 10 was prepared.

With respect to these copper alloys No. 1 to No. 10, strength, conductivity, spring limit value, bending formability, solderability, and solder embrittlement were evaluated. The results are shown in Table 1. . JIS-Z2241 for strength, JIS-H0505 for conductivity, JIS for spring limit value
-Evaluated based on H3130. The bending workability was represented by a value obtained by dividing the minimum bending radius (R) at which cracks occurred on the surface of the test piece by the thickness (t) of the test piece based on JIS-Z2248. The solderability is about 230 ° C
The test piece was immersed in a Pb-Sn-based eutectic solder bath for 5 seconds,
The wetting state of the solder was observed. Further, regarding the solder embrittlement, the test piece was immersed in a solder bath to perform soldering, and after being heat-treated at 150 ° C. for 500 hours in the air, taken out and bent at 180 degrees. The state of solder peeling on the surface was observed.

[0029]

[Table 1]

As shown in Table 1, the copper alloy of the present invention has good and balanced properties, whereas the comparative example 5 has poor solder embrittlement resistance, and the comparative examples 6 and 8 have poor solder embrittlement resistance. Poor solderability. In Comparative Examples 7, 9, and 10, cracks were generated by hot rolling. In Comparative Example 10, even when the cracks were removed and the above-described property evaluation was performed, the electrical conductivity was significantly reduced.

Example 2 Next, several ingots of substantially the same composition were produced from the copper alloy of the present invention having the composition No. 2 in Table 1 and produced under various conditions as shown in Table 2. Various properties shown in Table 2 were evaluated, and the results are also shown in Table 2. The production of hot-rolled cracks was discontinued because subsequent processing became difficult.

[0032]

[Table 2]

As shown in Table 2, the method of the present invention No. 1
1, good properties are obtained, but if the hot working conditions, the continuous annealing conditions, the first or second annealing conditions or the final working degree are out of the range of the present invention, the hot workability, strength, conductivity, spring It is clear that either the limit value or the bending workability deteriorates. This effect is the same in an alloy to which an appropriate amount of Sn is added.

[0034]

As described above, according to the present invention, Corson-based copper excellent in strength, spring property, conductivity and bending formability suitable for use in electric and electronic equipment parts such as terminals, connectors, lead frames and the like. Alloy can be manufactured at low cost,
It has a remarkable industrial effect.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C22F 1/08 C22C 9/00-9/10

Claims (4)

(57) [Claims] 1. Ni: 1.0 to 4.0 wt%, Si: 0.
1 to 1.0 wt%, Zn: 0.1 to 5.0 wt%, Mn:
A copper alloy containing 0.01 to 0.2 wt%, P: 0.01 wt% or less, and the balance of Cu and unavoidable impurities
Finish hot working at a temperature of 00 ° C or higher, then 10 ° C /
After quenching at a speed of at least 2 seconds, cold-work
Perform continuous annealing with recrystallization at 00 ° C or higher,
After quenching at a speed of at least
A method for producing a copper alloy for electric / electronic equipment, comprising annealing at 0 to 600 ° C. for 10 minutes to 5 hours. 2. Ni: 1.0 to 4.0 wt%, Si: 0.
1 to 1.0 wt%, Zn: 0.1 to 5.0 wt%, Mn:
A copper alloy containing 0.01 to 0.2 wt%, P: 0.01 wt% or less, and the balance of Cu and unavoidable impurities
Finish hot working at a temperature of 00 ° C or higher, then 10 ° C /
After quenching at a speed of at least 2 seconds, cold-work
Perform continuous annealing with recrystallization at 00 ° C or higher,
After quenching at a speed of at least
Anneal at 0 to 600 ° C. for 10 minutes to 5 hours, then perform cold working at a working degree of 40% or less,
A method for producing a copper alloy for electric / electronic equipment, comprising annealing at 500 ° C. for 1 minute to 5 hours. 3. Ni: 1.0 to 4.0 wt%, Si: 0.
1 to 1.0 wt%, Zn: 0.1 to 5.0 wt%, Mn:
0.01 to 0.2 wt%, Sn: 0.01 to 3.0 wt%,
P: Hot working of a copper alloy containing 0.01 wt% or less, the balance being Cu and unavoidable impurities, is completed at a temperature of 700 ° C. or more, and then rapidly cooled at a rate of 10 ° C./sec or more. After performing cold working, continuous annealing accompanied by recrystallization is performed at 700 ° C. or more, and then quenched at a rate of 10 ° C./second or more.
A method for producing a copper alloy for electric / electronic equipment, comprising annealing for 5 hours. 4. Ni: 1.0 to 4.0 wt%, Si: 0.
1 to 1.0 wt%, Zn: 0.1 to 5.0 wt%, Mn:
0.01 to 0.2 wt%, Sn: 0.01 to 3.0 wt%,
P: Hot working of a copper alloy containing 0.01 wt% or less, the balance being Cu and unavoidable impurities, is completed at a temperature of 700 ° C. or more, and then rapidly cooled at a rate of 10 ° C./sec or more. After performing cold working, continuous annealing accompanied by recrystallization is performed at 700 ° C. or more, and then quenched at a rate of 10 ° C./second or more.
Producing copper alloy for electrical and electronic equipment, wherein annealing is performed for 5 hours, then cold working is performed at a working ratio of 40% or less, and further annealing is performed at 250 to 500 ° C. for 1 minute to 5 hours. Method.