JPH05255779A - Production of copper alloy for electrical and electronic equipment - Google Patents

Abstract

PURPOSE:To provide the production of a copper allay for electrical and electronical equipments suitable as the lead frame material for an integrated circuit or the like and as the spring material for a connector, switch, relay or the like. CONSTITUTION:Hot working to a Cu alloy contg., by weight, 1.0 to 4.0% Ni, 0.1 to 1.0% Si, 0.1 to 5.0% Zn, 0.01 to 0.2% Mn and <=0.01% P, and the balance Cu with inevitable impurities is finished at >=700 deg.C. This alloy is rapidly cooled at >=10 deg.C/sec rate, is thereafter subjected to cold working, is furthermore subjected to continuous annealing accompanying recrystallization at >=700 deg.C, is subsequently subjected to rapid cooling at >=10 deg.C/sec rate, is thereafter subjected to cold working and is subjected to annealing at 400 to 600 deg.C for 10min to 5hr. In this way, the objective Corson alloy having excellent strength, spring properties, electrical conductivity and bending formability as electrical and electronical equipment parts can be manufactured at a low cost.

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 lead frame materials such as transistors and integrated circuits (IC), and also for spring materials such as terminals, connectors, switches and relays. Is.

[0002]

2. Description of the Related Art Materials for electric and electronic devices, for example, semiconductor device materials typified by lead frame materials and conductive materials typified by springs, connectors, switches, etc. for electric devices have hitherto been brass, phosphor bronze, Sn. Copper containing copper and copper containing Fe were used. However, with the downsizing, weight reduction and density increase of electrical and electronic equipment, there is a strong demand for a high balance of strength, elasticity and conductivity for these materials, making it difficult for conventional alloys to meet these requirements. Is the current situation. Therefore, Cu- which is excellent in these characteristics and is inexpensive
Ni-Si type so-called Corson type copper alloys have come to be used.

However, although this Corson type copper alloy is excellent in practical properties such as the strength, spring property and conductivity, it has not been widely used because it has a remarkable defect in terms of manufacturability. .. That is, in the production of Corson type copper alloy, brittle cracking occurs due to the effect of residual stress during casting and solidification during heating and temperature rise for hot rolling, especially in the temperature range of 300 to 600 ° C. This adversely affects rolling, resulting in a significant decrease in yield.

Further, in order to obtain good strength and conductivity, it is necessary to carry out quenching treatment (solution treatment) after holding at high temperature in the Corson type copper alloy, and as a annealing method for this purpose, batch annealing has been conventionally used. However, there is a problem that the manufacturing process is complicated and the cost is high. In addition, when the strip material is annealed in a coiled state, a bending stress is generated on the surface, and this stress may act in the same manner as the above residual stress to cause brittle cracking as described above. It was In this case, the yield will be significantly reduced in the subsequent cold rolling.

On the other hand, when the solution treatment is carried out 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 due to the cold working is caused. Therefore, there is a problem that ductility such as bending formability is significantly reduced due to the occurrence of the above phenomenon.

From such a background, there has been a strong demand for manufacturing a Corson-type copper alloy to improve the yield, reduce the manufacturing cost by simplifying the process, and improve the performance such as moldability.

[0007]

The present invention has been made as a result of extensive studies in view of the above points, and the purpose thereof is C
In the method of manufacturing the u-Ni-Si alloy, the strength and spring property are improved by using the continuous annealing method without adopting the batch method that improves the hot rolling property and increases the manufacturing cost when performing solution annealing. The present invention also provides a method capable of producing a copper alloy for electric and electronic devices, which has excellent conductivity and good bending formability, at low cost.

That is, according to the present invention, 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: 0.01-3.0 wt%
Of the copper alloy containing Cu and the balance Cu and unavoidable impurities is terminated at a temperature of 700 ° C. or higher, and then 1
After quenching at a rate of 0 ° C / sec or more, cold working is performed, continuous annealing accompanied by recrystallization is performed at 700 ° C or more, and then rapid cooling at a rate of 10 ° C / sec or more, followed by cold working. Annealing at 400 to 600 ° C. for 10 minutes to 5 hours, or after this heat treatment, cold working is performed at a working degree of 40% or less, and further annealing at 250 to 500 ° C. for 1 minute to 5 hours. It is a thing.

[0009]

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

Both Ni and Si are elements that impart strength, elasticity and conductivity, and the Ni content is 1.0 to 4.
The limitation to 0 wt% is that if Ni is less than 1.0 wt%, Si
This is because it is difficult to obtain high strength and high conductivity even if the content of Ni is 0.1 wt% or more, and if the content of Ni exceeds 4.0 wt%, the conductivity and bending formability are deteriorated. ..

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

Zn is a heat-resistant peeling property of solder and Sn plating,
It is an element that improves the migration resistance, and the reason why it is limited to 0.1 to 5.0 wt% is that the above effects are less than 0.1 wt%, and the conductivity and solder content are higher than 5.0 wt%. This is because the attachability is reduced.

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

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

It has been found that hot workability and embrittlement during annealing can be significantly improved if the optimum amount of Mn is added and the P content is controlled together. However, if it is not controlled to an appropriate amount, the improvement effect is small.

Sn is an element that improves the strength, spring property and bend formability, and the content thereof is limited to 0.01 to 3.0 wt%. This is because if it exceeds 0.0 wt%, the 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 is finished at a temperature of 700 ° C. or higher, that is, the end temperature of the hot working is 700 ° C. or higher, and the quenching rate thereafter is limited to 10 ° C./sec or higher is as follows. If the temperature is less than 700 ° C, solution treatment is incomplete even if it is rapidly cooled at a rate of 10 ° C / sec or more, and precipitation occurs, which adversely affects the solution treatment in the subsequent continuous annealing, resulting in deterioration of strength and springiness. Because it does. Furthermore, embrittlement cracking occurs during hot working, which makes subsequent cold working difficult.

The reason for limiting the quenching rate to 10 ° C./sec or more is that if the quenching rate is less than 10 ° C./sec, precipitation occurs during cooling even if the end temperature of hot working is 700 ° C. or more, and the solution is continuously annealed. This is because even if the chemical treatment is performed, good strength and springiness cannot be finally obtained.

Next, the reason for adopting the continuous annealing method as the annealing method is that brittle cracking due to batch annealing is prevented and the process is simplified, so that the manufacturing cost is greatly reduced.

The reason for limiting the continuous annealing temperature to 700 ° C. or higher and the subsequent quenching rate to 10 ° C./sec or higher is 7
This is because at a temperature of less than 00 ° C, recrystallization does not occur and the final bendability is significantly deteriorated, and at a temperature of less than 700 ° C and a cooling rate of less than 10 ° C / sec, solution treatment is incomplete. This is because precipitation occurs and the ultimate strength and spring properties deteriorate.

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

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

After the above heat treatment, if necessary, cold working is performed at a working ratio of 40% or less. The reason why cold working exceeding 40% is that anisotropy increases and bending formability remarkably decreases. This is because

The reason for further annealing at 250 ° C. to 500 ° C. for 1 minute to 5 hours is to remove the local stress and improve the spring property, but if the annealing temperature is less than 250 ° C., the effect is small and 500 This is because if the temperature exceeds ° C, the strength and the elasticity will be deteriorated. Also, if the annealing time is less than 1 minute, the effect is small, and if the annealing time is more than 5 hours, the effect is not changed but the energy is wasted. The same effect can be obtained regardless of whether the annealing method is the batch method or the running method.

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

[0026]

EXAMPLES Next, the present invention will be specifically described by way of 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, and then 750 ° C. to 50 ° C.
It was rapidly cooled at a cooling rate of ° C / sec. This rolled material is 10mm thick
After chamfering, cold rolling with a workability of 94%, continuous annealing at 850 ° C., and rapid cooling at a rate of 100 ° C./sec. Subsequently, cold rolling was performed at a working rate of 40%, and annealing was performed at 460 ° C. for 2 hours. Further, this annealed material was subjected to cold rolling with a workability of 20%, and then annealed at 400 ° C. for 2 hours to invent example copper alloys No. 1 to No. 4 and comparative example copper alloy No. 5.
~ No. 10 was prepared.

These copper alloys No. 1 to No. 10 were evaluated for strength, conductivity, spring limit value, bending formability, solderability and solder embrittlement, and 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 is indicated by a value obtained by dividing the minimum bending radius (R) at which cracks occur on the surface of the test piece by the thickness (t) of the test piece based on JIS-Z2248. Also, solderability is about 230 ℃
The test piece in the Pb-Sn-based eutectic solder bath of
The wet state of the solder was observed. Regarding the solder embrittlement property, the test piece was dipped in a solder bath for soldering, heat-treated in the atmosphere at 150 ° C. for 500 hours, taken out, and then bent 180 degrees. The state of solder peeling on the surface was observed.

[0029]

[Table 1]

As shown in Table 1, the copper alloys of the present invention provide good and well-balanced properties, while Comparative Example 5 deteriorates the solder embrittlement resistance and Comparative Examples 6 and 8 Poor solderability. Further, in Comparative Examples 7, 9 and 10, cracks occurred due to hot rolling, and in Comparative Example 10, even if the cracked portion was removed and the above-mentioned characteristic evaluation was performed, the conductivity was significantly reduced.

Example 2 Next, with respect to the copper alloy of the present invention having the composition of No. 2 in Table 1, several ingots having almost the same composition were produced 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. In addition, about the thing which the hot rolling crack generate | occur | produced, since the subsequent processing became difficult, manufacture was discontinued.

[0032]

[Table 2]

As shown in Table 2, the production method No. 1 of the present invention example
1, good properties are obtained, but if hot working conditions, continuous annealing conditions, first or second annealing conditions or the final working ratio deviate from the scope of the present invention, hot workability, strength, conductivity, spring It is clear that either the limit value or bending workability deteriorates. This effect is also the same for alloys containing an appropriate amount of Sn.

[0034]

As described above, according to the present invention, a 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 and lead frames. The alloy can be manufactured at low cost,
It has a remarkable industrial effect.

Claims (4)

[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% and P: 0.01 wt% or less, the balance being Cu and unavoidable impurities,
Hot working is completed at a temperature of 00 ° C or higher, then 10 ° C /
After quenching at a speed of more than 2 seconds, cold working is performed and further 7
Continuous annealing with recrystallization is performed at 00 ° C or higher, then 10
After quenching at a speed of ℃ / sec or more, cold working is performed to 40
A method for producing a copper alloy for electric and electronic equipment, which comprises performing 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% and P: 0.01 wt% or less, the balance being Cu and unavoidable impurities,
Hot working is completed at a temperature of 00 ° C or higher, then 10 ° C /
After quenching at a speed of more than 2 seconds, cold working is performed and further 7
Continuous annealing with recrystallization is performed at 00 ° C or higher, then 10
After quenching at a speed of ℃ / sec or more, cold working is performed to 40
Annealing is performed at 0 to 600 ° C. for 10 minutes to 5 hours, then cold working is performed at a working degree of 40% or less, and further 250 to
A method for producing a copper alloy for electric and electronic equipment, which comprises performing 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:
0.01-0.2 wt%, Sn: 0.01-3.0 wt%,
P: 0.01 wt% or less, a copper alloy containing the balance Cu and unavoidable impurities is hot-worked at a temperature of 700 ° C. or higher, then rapidly cooled at a rate of 10 ° C./sec or higher, and then cooled. Cold working, further continuous annealing accompanied by recrystallization at 700 ° C. or higher, and then rapidly cooled at a rate of 10 ° C./sec or higher, and then cold working at 400 to 600 ° C. for 10 minutes to
A method for producing a copper alloy for electric and electronic equipment, which comprises performing 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:
0.01-0.2 wt%, Sn: 0.01-3.0 wt%,
P: 0.01 wt% or less, a copper alloy containing the balance Cu and unavoidable impurities is hot-worked at a temperature of 700 ° C. or higher, then rapidly cooled at a rate of 10 ° C./sec or higher, and then cooled. Cold working, further continuous annealing accompanied by recrystallization at 700 ° C. or higher, and then rapidly cooled at a rate of 10 ° C./sec or higher, and then cold working at 400 to 600 ° C. for 10 minutes to
Manufacture of a copper alloy for electric and electronic equipment, characterized by performing annealing for 5 hours, then performing cold working at a working degree of 40% or less, and further annealing at 250 to 500 ° C. for 1 minute to 5 hours. Method.