JP2005298910A - Copper alloy plate for conductive parts and manufacturing method thereof - Google Patents

Abstract

A copper alloy material having characteristics suitable for thin plate conductive parts is provided.
Ni: 0.1-3.0%, Sn: 0.1-2.0%, P: 0.01-0.3%, the balance being Cu and inevitable impurities, preferably Ni / P is 10-30, 0.2% proof stress is 600 N / mm ² or more, conductivity is 35% IACS or more, Young's modulus is 120 kN / mm ² or more, spring limit value is 400 N / mm ² or more, A copper composite material for thin plate conductive parts having a plate thickness of preferably 0.15 mm or less. This alloy material is a heat treatment in which the alloy plate material having the above composition is heated to 300 to 750 ° C. and then rapidly cooled, cold rolled to reduce the plate thickness to 0.15 mm or less at a rolling rate of 10% or more, and heated to 150 to 600 ° C. It can manufacture by performing the heat processing to perform sequentially.
[Selection figure] None

Description

  The present invention relates to a copper alloy material suitable for electrical / electronic parts such as connectors, switches, relays, etc., and particularly conductive parts having a thin plate thickness, and a method for manufacturing the same.

  In recent years, electrical wiring of information communication devices, home appliances, automobile parts, etc. has become more complex and highly integrated. Along with this, the demand for copper products used for electrical and electronic parts such as connectors, switches and relays is increasing.

Conventionally, brass and phosphor bronze have been generally used for conductive parts such as connectors.
Brass is selected as a low cost material. However, the tensile strength does not exceed 600 N / mm ² even if the type is EH, and is not necessarily sufficient in terms of strength as a thin plate electrical contact material. In addition, the corrosion resistance, stress corrosion cracking resistance, and stress relaxation resistance are somewhat inferior, and use is restricted depending on the application.
Phosphor bronze has an excellent balance of strength, corrosion resistance, stress corrosion cracking resistance, and stress relaxation resistance. However, the conductivity is as small as 12% IACS, for example, for spring phosphor bronze. In addition, the material cost is high.

  Therefore, various copper alloys have been researched, developed and proposed. In particular, the following Patent Document 1 discloses a copper-based alloy for terminals in which Ni—P-based precipitates are uniformly dispersed. This balances moderate high performance in all of tensile strength, spring limit value, electrical conductivity, stress relaxation resistance and bending workability, and is a useful material for many conductive applications such as connectors. .

Japanese Patent Laid-Open No. 10-226835

  In recent years, electric and electronic parts tend to be reduced in size and weight, and conductive parts used for such parts are inevitably required to be thinner and thinner. In order to meet this demand, a material that exhibits excellent durability and high reliability even when it is thinned is desired. Specifically, it is important to have a higher strength and elasticity (Young's modulus) as well as exhibiting a higher level of strength and conductivity than before. Moreover, when improving them, corrosion resistance and press formability to a complicated shape must not be deteriorated. In addition, an increase in material costs must be avoided.

As described above, the copper alloy material disclosed in Patent Document 1 has a good balance of strength and conductivity, and is particularly suitable for use as a conductive component having a plate thickness of about 0.2 mm, which has been the mainstream in the past. There was no problem. However, in recent years, the need for a plate thickness of 0.15 mm or less or less has increased. Specifically, there is an increasing demand for thin plate conductive parts such as 0.10 mm, 0.08 mm, and 0.05 mm. The copper alloy material of Patent Document 1 may be insufficient in strength level for use in these ultra-thin parts, and the Young's modulus is about 115 kN / mm ^2, which is not sufficient. That is, there was a lack of reliability for ultrathin conductive parts.

  The present invention provides a copper alloy material that has excellent mechanical characteristics that can sufficiently cope with the thinning of conductive parts as described above, and that also has basic characteristics such as corrosion resistance and conductivity required for conductive parts. It is intended to supply stably while suppressing the increase.

As a result of investigations by the inventors, it has been clarified that the above object can be realized based on a copper alloy having the composition disclosed in Patent Document 1. That is, the materials provided by the present invention are Ni: 0.1-3.0%, Sn: 0.1-2.0%, P: 0.01-0.3%, the balance being Cu and inevitable impurities consists, preferably satisfies the following equation (1), 0.2% proof stress 600N / mm ² or more, conductivity of 35% IACS or more, a Young's modulus of 120 kN / mm ² or more, the spring limit value 400 N / mm ² The above copper alloy, preferably a copper alloy plate for a thin plate conductive part having a plate thickness of 0.15 mm or less.
10 ≦ Ni / P ≦ 30 (1)
Here, the contents of these elements expressed in mass% are substituted for Ni and P in the formula (1). The “copper alloy plate” includes a strip.

  A conductive coating layer can be formed on the alloy material. In particular, a material having a Cu plating layer having a thickness of 0.3 to 2.0 μm and a Sn plating layer having a thickness of 0.5 to 5.0 μm thereon is provided.

Further, the copper alloy plate for conductive parts is a copper alloy material having the predetermined composition,
Heat treatment to be rapidly cooled after heating to 300-750 ° C.,
Cold rolling to reduce the sheet thickness to 0.15 mm or less at a rolling rate of 10% or more,
Heat treatment to heat to 150-600 ° C.,
Can be manufactured by a method of sequentially applying the above.

  When a Cu plating layer having a thickness of 0.3 to 2.0 μm and a Sn plating layer having a thickness of 0.5 to 5.0 μm are formed on the surface, a heat treatment is performed by heating to 100 to 200 ° C. Manufacturing method is adopted.

  According to the present invention, with conventional materials, it was difficult to balance mechanical properties, electrical conductivity, and corrosion resistance at a high level, and thus a thin plate conductive component having a thickness of 0.15 mm or less or less could not be realized. It became possible to stably provide a copper alloy material suitable for the above. Therefore, the present invention contributes to reducing the size and weight of electrical / electronic components.

[Chemical composition]
Ni is an element that dissolves in the Cu matrix and contributes to improvement in strength, elasticity, heat resistance, stress relaxation resistance, and migration resistance of the base material. Furthermore, it contributes to the improvement of electrical conductivity by forming a compound with P to be dispersed and precipitated. In order to fully exhibit these effects, Ni content of 0.1% by mass or more is necessary. However, if it exceeds 3.0% by mass, the effect is saturated and uneconomical. Therefore, the Ni content is specified to be 0.1 to 3.0% by mass.

  Sn is an element that improves the strength, elasticity and corrosion resistance by dissolving in the matrix of the base material. When the Sn content is less than 0.1% by mass, the strength and elasticity cannot be improved sufficiently. On the other hand, if it exceeds 2.0% by mass, the effect becomes saturated and uneconomical. Therefore, Sn content is prescribed | regulated to 0.1-2.0 mass%.

  P acts as a deoxidizer for the molten metal, and improves the electrical conductivity and the tensile strength, elasticity, and stress relaxation resistance properties by dispersing and precipitating a compound with Ni. If the P content is less than 0.01% by mass, these effects cannot be obtained sufficiently. However, if it exceeds 0.3% by mass, the electrical conductivity, workability and solder weather resistance will be significantly reduced even in the presence of Ni, and further the migration resistance will be reduced. Therefore, the P content is defined as 0.01 to 0.3% by mass.

The remainder consists essentially of Cu.
In the present invention, as described above, since the strength and conductivity are improved by utilizing the dispersion precipitation of the compound of Ni and P (Ni-P compound), the ratio of Ni / P content (% by mass). Is preferably in the range of 10-30.

〔Material property〕
A connector, which is an important application as a conductive component, needs to be strong enough not to buckle or deform against stress load or bending at the time of insertion, and also needs to have strength against crimping and holding of an electric wire. Assuming a thin plate material having a thickness of 0.15 mm or less or less, the 0.2% proof stress should be 600 N / mm ² or more, and preferably 650 N / mm ² or more. The spring limit value is required to be 400 N / mm ² or more, preferably 500 N / mm ² or more, more preferably 520 N / mm ² or more. Tensile strength it is desirable to ensure a 630 N / mm ² or more.

Recently, the connector itself has been downsized, and a structure in which the spring displacement is made small with a material having a large Young's modulus is advantageous. That is, a material having a high Young's modulus capable of obtaining a large stress with a small displacement is desired. In particular, when a thin plate material having a thickness of 0.15 mm or less or less is used, the Young's modulus is required to be 120 kN / mm ² or more, and more preferably 130 kN / mm ² or more.
Due to the downsizing of the connector, the demand for press formability becomes strict, and the workability that satisfies the ratio R / t of the bending portion radius (R) to the plate thickness (t) of 1 or less is desired.

  Regarding conductivity, in order to sufficiently suppress the generation of Joule heat at the time of energization especially in a conductive part having a thickness of 0.15 mm or less, a conductivity of 35% IACS or more is necessary, and preferably 40% IACS or more is desirable. It is where

  Furthermore, it is desired to have excellent corrosion resistance and stress corrosion cracking resistance, and since a thermal load is applied to the female terminal, it is also important to have excellent stress relaxation characteristics. Specifically, it is desirable that the stress corrosion cracking life is 3 times or more of one type of conventional brass, and the stress relaxation rate is 25% or less where the relaxation rate of 150 ° C. × 500 hours is half that of one type of brass.

〔surface treatment〕
The above copper alloy plate can be provided with a conductive surface coating. For example, a Cu plating layer having a thickness of 0.3 to 2.0 μm on the surface and a Sn plating layer having a thickness of 0.5 to 5.0 μm thereon have higher durability in a connector or the like.

[Production method]
The copper alloy plate for conductive parts having the above-described characteristics can be manufactured as follows.
First, a copper alloy having the above composition is melted and hot-rolled by a normal method, and cold rolling and annealing are repeated to produce an intermediate product (annealed material). The sheet thickness of this intermediate product is cold rolled without intermediate annealing to the final sheet thickness of 0.15 mm or less in the final cold rolling (hereinafter referred to as “finished cold rolling”) performed thereafter. It is necessary to make the plate thickness that enables this. However, the plate thickness of the intermediate product is set so that a rolling rate of at least 10% or more can be secured by finish cold rolling.

  In the final heat treatment for producing the intermediate product, it is important that the material is heated to 300 to 750 ° C. and then rapidly cooled by water cooling or the like. Although the holding time in the said temperature range can be 1-360 minutes, it is desirable to set it as about 30-120 minutes normally. The heating temperature range is preferably 450 to 650 ° C, more preferably 500 to 600 ° C. After cooling, the surface oxide scale is removed by pickling or the like.

  Next, finish cold rolling is performed. Here, it is necessary to reduce the plate thickness to 0.15 mm or less and to ensure a rolling rate of at least 10%. If possible, it is desirable to secure a rolling rate of 50% or more. In order to reduce the plate thickness to such a thin region, it is necessary to focus on preventing the generation of herringbone. In particular, in the case of an extremely thin material such as 0.10 mm and 0.05 mm, attention must be paid to securing the plate thickness accuracy. Such a thin plate can be rolled by applying a tension of about twice the normal cold rolling to the plate. Specifically, it is desirable to apply a tension of 30% or more to the 0.2% yield strength of the material immediately after finish cold rolling.

Subsequently, the heat processing which heats material to 150-600 degreeC is performed. Although the holding time in the above temperature range can be carried out over a wide range of 5 seconds to 180 minutes, it is usually desirable to be about 10 to 60 minutes. The heating temperature range is more preferably 200 to 350 ° C. It is desirable to pickle even after this heat treatment.
In this way, a copper alloy plate having the above-described excellent characteristics can be obtained.

  When the Cu plating layer having a thickness of 0.3 to 2.0 μm and the Sn plating layer having a thickness of 0.5 to 5.0 μm are applied on the surface of the copper alloy plate, the temperature is 100 to 200 ° C. after plating. It is desirable to heat the material in the temperature range. By this heat treatment, the spring limit value is improved and the hardening at the bent portion is increased, which is further advantageous as a connector material.

  In addition, when using the stamping waste of the material which has Sn plating layer as a raw material of an alloy, the said waste is previously hold | maintained at 300-600 degreeC and 0.5 to 24 hours in air | atmosphere or inert gas atmosphere before melt | dissolution. It is desirable to be subjected to heat treatment.

A copper alloy in which the contents of Ni, Sn, and P were adjusted was melted using a high frequency induction melting furnace to obtain a 40 mm × 40 mm × 150 mm ingot. At that time, the atmosphere from melting to casting was an Ar gas atmosphere, and water-cooled immediately after casting.
After each ingot was hot-rolled, cold rolling and annealing were repeated to obtain an intermediate product (annealed material) having a plate thickness of 0.5 to 1.4 mm. The final heat treatment for producing the intermediate product was performed by water quenching after holding at 550 ° C. for 60 minutes.

  Thereafter, pickling was performed, and cold rolling was finally performed at a rolling rate of 10% or more to a plate thickness of 0.08 mm, 0.10, or 0.25 mm (finish cold rolling). At the time of finish cold rolling, the tension is applied to the final sheet thickness while applying tensions of 19%, 27%, 37% and 44% to the 0.2% proof stress immediately after the finish cold rolling of each material. We tried hot rolling to investigate the occurrence of herringbone.

  Next, heat treatment was performed on the material that was rolled by the finish rolling with 44% of 0.2% proof stress and held at 150 to 350 ° C. for 30 minutes. This heat treatment is referred to herein as “low temperature annealing”. Then, it pickled.

Using the copper alloy sheet obtained as described above as a test material, conductivity, Vickers hardness, tensile properties (tensile strength σ _B , 0.2% proof stress σ _0.2 ), spring limit value, bending workability, Young The rate was determined.
The electrical conductivity was determined in accordance with JIS Z 2244, the Vickers hardness was determined in accordance with JIS Z 2244, the tensile property was determined in accordance with JIS Z 2241, the spring limit was determined in accordance with JIS H 3130, and the Young's modulus was determined in accordance with JIS Z 2280.
The bending workability is 90 ° W bending test (CES-M-0002-6, R = 0.1 mm, R / t = 1.25, W = 10 mm, rolling direction), and the central mountain surface is good. An evaluation was given as “◯”, a case where wrinkles occurred was evaluated as “Δ”, and a case where cracks occurred was evaluated as “X”.

The results are shown in Table 1.
The tensile strength σ _B , 0.2% proof stress σ _0.2 , spring limit value, Young's modulus test pieces were all set so that the longitudinal direction was perpendicular to the rolling direction (TD).
In the bending workability in Table 1, “GW (R = 0)” means that the bending axis is perpendicular to the rolling direction and the bending radius R is 0, and “BW (R = 0.1)” means that the bending axis is the rolling direction. , And the bending radius R is 0.1 mm.

As can be seen from Table 1, Nos. 1 to 10, which are examples of the present invention, sufficiently clear 0.2% proof stress of 600 N / mm ² or more despite the thin plate thickness of 0.08 to 0.10 mm. In addition, the Young's modulus exceeded 120 kN / mm ² with a margin. C5210 of the comparative example is a conventional phosphor bronze, but has an excellent electrical conductivity, and also has excellent bending workability and Young's modulus.
In Comparative Example No. 11, the sheet thickness was only reduced to 0.25 mm by finish cold rolling, so the 0.2% proof stress did not reach 600 N / mm ² .

  Table 2 shows the influence of tension on the herringbone generation during finish cold rolling.

  As can be seen from Table 2, when the plate thickness is about 0.25 mm, a good surface without a herringbone can be easily obtained without applying particularly high tension. On the other hand, when the target plate thickness is an extremely thin level of 0.08 to 0.10 mm, it is difficult to prevent the generation of herringbone unless the tension is increased.

Claims (7)

In mass%, Ni: 0.1-3.0%, Sn: 0.1-2.0%, P: 0.01-0.3%, the balance is composed of Cu and inevitable impurities , 0.2% proof stress 600N / mm ² or more, conductivity of 35% IACS or more, a Young's modulus of 120 kN / mm ² or more, the copper alloy is spring limit value 400 N / mm ² or more. Ni: 0.1 to 3.0%, Sn: 0.1 to 2.0%, P: 0.01 to 0.3%, the balance being Cu and inevitable impurities, and the following ( 1) it has a composition satisfying the formula, 0.2% proof stress 600N / mm ² or more, conductivity of 35% IACS or more, a Young's modulus of 120 kN / mm ² or more, the spring limit value is 400 N / mm ² or more Copper alloy.
10 ≦ Ni / P ≦ 30 (1)   A copper alloy plate for conductive parts, wherein the copper alloy according to claim 1 or 2 has a thickness of 0.15 mm or less.   A copper alloy or copper alloy plate for a conductive component, comprising a conductive coating layer on the surface of the copper alloy or copper alloy plate according to claim 1.   A Cu plating layer having a thickness of 0.3 to 2.0 μm and a Sn plating layer having a thickness of 0.5 to 5.0 μm thereon on the surface of the copper alloy or copper alloy plate according to claim 1. Copper alloy or copper alloy plate for conductive parts having Ni: 0.1 to 3.0%, Sn: 0.1 to 2.0%, P: 0.01 to 0.3%, the balance being Cu and inevitable impurities, and the following ( For copper alloy sheets with a composition that satisfies the formula (1)
Heat treatment to be rapidly cooled after heating to 300-750 ° C.,
Cold rolling to reduce the sheet thickness to 0.15 mm or less at a rolling rate of 10% or more,
Heat treatment to heat to 150-600 ° C.,
The copper alloy plate for conductive parts having a 0.2% proof stress of 600 N / mm ² or more, a conductivity of 35% IACS or more, a Young's modulus of 120 kN / mm ² or more, and a spring limit value of 400 N / mm ² or more. Manufacturing method.
10 ≦ Ni / P ≦ 30 (1) Ni: 0.1 to 3.0%, Sn: 0.1 to 2.0%, P: 0.01 to 0.3%, the balance being Cu and inevitable impurities, and the following ( For copper alloy sheets with a composition that satisfies the formula (1)
Heat treatment to be rapidly cooled after heating to 300-750 ° C.,
Cold rolling to reduce the sheet thickness to 0.15 mm or less at a rolling rate of 10% or more,
Heat treatment to heat to 150-600 ° C.,
Alloy sheet obtained by sequentially applying 0.2% proof stress, having a 0.2% proof stress of 600 N / mm ² or more, a conductivity of 35% IACS or more, a Young's modulus of 120 kN / mm ² or more, and a spring limit value of 400 N / mm ² or more. A Cu plating with a thickness of 0.3 to 2.0 μm is applied to the surface of the film, and a Sn plating with a thickness of 0.5 to 5.0 μm is further applied thereon, followed by a heat treatment to be heated to 100 to 200 ° C. The manufacturing method of the copper alloy plate for conductive parts.
10 ≦ Ni / P ≦ 30 (1)