JPH03188247A - Production of high strength and high conductivity copper alloy excellent in bendability - Google Patents

Abstract

PURPOSE:To produce a high strength and high conductivity copper alloy having superior bendability by subjecting a copper alloy with a specific composition to solution treatment at specific temp., to final cold working at a specific draft, and then to ageing treatment at a specific temp. CONSTITUTION:A copper alloy which has a composition consisting of, by weight, 0.4-4.0% Ni, 0.1-1.0% Si, 0.1-3.5% Sn, and the balance Cu with inevitable impurities and satisfying [wt.% Ni]+[wt.% Si]+[wt.% Sn]<5.0 is produced. This copper alloy is subjected, in succession, to final solution treatment at >=700 deg.C for regulating crystalline grain size to 1-10mum, to final cold rolling at <40% draft, and then to ageing treatment at 300-700 deg.C. By this method, this copper alloy can meet the recent demand for the miniaturization of electronic parts and the thinning of material.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The manufacturing method of the present invention can be applied to products in all fields that require good bending workability, including electronic parts, and in some cases, high springiness. It can be used for manufacturing.

[Prior Art] Conventionally, copper alloys such as brass, nickel silver, phosphor bronze, and beryllium copper, and iron alloys such as stainless steel have been used for electronic components that require strength. Among these materials for electronic parts, nickel silver has a beautiful luster, good malleability, fatigue resistance, and corrosion resistance, and is suitable for switches for electronic, communication, information, and electrical measuring equipment.
Widely used in connectors and relays.

Incidentally, in recent years, miniaturization of components has progressed rapidly in various fields. As parts become smaller, the materials must also be thinner, so they must have higher strength. Furthermore, since the heat capacity of the component becomes small, it is necessary that the heat generated during energization is small and that the material has excellent heat dissipation properties, so the material must be highly conductive. Furthermore, since the bending radius of the bent portion of the material is also small, the material must have excellent bending properties.

However, the strengthening mechanism of nickel silver is due to a combination of solid solution strengthening of Ni and Zn in Cu and work hardening by cold working (rolling). , Ni, and Zn concentrations must be lowered and the degree of cold rolling must be increased, resulting in poor bending workability. In particular, the bending workability in the direction in which the bending axis is parallel to the rolling direction becomes poor. Further, there is a limit to the improvement in strength by work hardening of nickel silver with low Ni and Zn concentrations. The currently used JIS standard nickel silver for springs (7701) has high strength and extremely good bending workability, but it has low electrical conductivity and contains 18% of expensive Ni, so it cannot be used with bare metal. The cost is also high.

On the other hand, the Snn-added Corsin alloy, Cu5NiSSi, is targeted by the manufacturing method of the present invention.

It is a high-strength, highly conductive copper alloy whose main component is Sn.

The strengthening mechanism of this alloy is precipitation hardening due to Ni5Si and S
This is a combination of solid solution strengthening by n. Generally, Corson alloy strips have extremely poor bending workability like other dispersion-strengthened copper alloys. In addition, the addition of Sn to Corson alloy is
This further deteriorates bending workability. For this reason, Sn-added Corson alloys are currently only used as materials for applications that do not undergo severe bending, such as IC lead frames.

[Problems to be Solved by the Invention] As mentioned above, with the miniaturization of parts, materials are required to have high strength, high conductivity, and good bending workability. S is inherently high strength and highly conductive.
Improvement of the bending workability of nn-added Corsin alloys has been an issue.

[Means for Solving the Problems] In view of the above points, the present invention provides a method for manufacturing a high-strength, high-conductivity copper alloy with excellent bending workability.

That is, in the present invention, Ni0.4 to 4.0wt%, S
i 0.1-1.0wt%, Sn 0.1-3.
5 wt%, and [wt%Ni+[wt%S
i]+[wt%Sn]<5.0, or further as a subcomponent, F e SM g s A l , Cr s
M n SCo s Z n s T l s Z r
% P b SCd SI n SA g s In the production of a copper alloy containing 0.001 to 2.0 wt% of one or more of two or more of P, and the balance being Cu and unavoidable impurities, (1) Grain size is Final solution treatment at a temperature of 700°C or higher to adjust the volume to 1 to 10 μl (1) Final cold rolling with a working degree of less than 40% (1) 3
A process consisting of an aging treatment at a temperature of 00 to 700 °C, or (1) a final solution treatment at a temperature of 700 °C or higher to carefully adjust the grain size to 1 to 10μ; (1) immediately after the final solution treatment; Processing rate X% (0≦x40
) Cold rolling (III) Aging treatment at a temperature of 300-700°C (
ff) Machining degree Y% (0(I1-(1-X/100)(1
Final cold rolling (V) of -Y/100)l be.

[Detailed description of the invention] Next, the reasons for limiting each component and manufacturing conditions of the present invention will be described.

The reason why the Ni content is set to 0.4 to 4.0 wt% in the present invention is that when the Ni content is less than 0.4 wt%, even if St is co-added and an aging treatment is performed, the strength is low and the spring property is insufficient. not,
This is because when the Ni content exceeds 4.0 wt%, strength is obtained, but conductivity decreases and soldering properties deteriorate significantly. The reason for limiting the Si content to 0.1 to 1.0 wt% is that if the Ni content is less than 0.1 wt%, high conductivity cannot be obtained even if Ni is co-added and an aging treatment is performed. 1.
If it exceeds 0 wt%, workability and conductivity will decrease significantly,
This is because soldering also deteriorates the properties.

The reason for containing Sn is to expect solid solution strengthening by Sn, since precipitation hardening by Ni and St alone is insufficient for strength and spring properties, and if it is less than 0.1 wt%, there is no effect; When it exceeds .5vt%, the conductivity decreases,
Moreover, hot workability also deteriorates. Also, Ni, Si
, the content of Sn is [wt%Nil+[wt%Si]+[
wt%Sn]<5.0 because bending workability deteriorates at 5.0wt% or more.

In addition, as a subcomponent, F e s M g s A I
SCr 5Mn5Co, Z n ST i s Z r
SP b % Cd sI n N A g s P
One or more of these in total amount o, oot ~ 2.0w
The reason for adding t% is to improve strength and spring characteristics by adding these subcomponents, but 0.t% is added.
This is because if it is less than 0.001 wt%, there is no effect, and if it exceeds 2.0 wt%, the conductivity will decrease and the workability will also deteriorate.

Next, the solution treatment is performed in order to obtain a material with high strength and high conductivity in the subsequent aging treatment. The reason why the treatment temperature is set to 700° C. or higher is that if the temperature is lower than 700° C., depending on the composition of Ni5Si, Ni and St will not form a solid solution, making it impossible to obtain the high strength characteristic of age-hardening copper alloys. Further, the reason why the crystal grain size is set to 1 to 10 μm layer is because the crystal grain size greatly affects bending workability. If the crystal grain size is less than 1 μm, the structure will be a mixture of unrecrystallized portions and recrystallized portions, resulting in poor bending workability and the material becoming susceptible to cracking.
If it exceeds lOμ-, roughness tends to occur along the grain boundaries, and if the bending radius is small, cracks may occur.

The reason why cold rolling is performed once or twice after solution treatment is to obtain strength through work hardening.

The reason why the degree of workability of cold rolling is less than 40% is that if it is more than 40%, the development of texture due to rolling will occur significantly, the anisotropy will increase, and the bending workability with the bending axis parallel to the rolling direction will decrease. This is because it deteriorates significantly.

In addition, in the manufacturing method of the present invention, it is essential to specify the total concentration of Nf, Si, and Sn, grain size, and cold rolling workability in order to obtain good bending workability, and all of them are specified. Unless these conditions are met, a material with good bendability cannot be obtained.

Aging treatment is necessary to improve strength and conductivity, but the reason why the aging treatment temperature is set at 300 to 700°C is as follows.
At temperatures below 300°C, aging takes a long time and is not economical; at temperatures above 700°C, depending on the composition of Ni5Si, Nl s S t may form a solid solution, reducing the strength and strength that are characteristic of age-hardening alloys. This is because conductivity cannot be obtained. For actual operation, aging treatment at 420 to 480°C is recommended.

The reason why heat treatment is performed without recrystallization at a temperature of 150 to 800°C is to further improve spring properties and bending workability by performing heat treatment without recrystallization after cold working. (If the temperature exceeds 800°C, the heat treatment time will be shortened and it will be difficult to control the properties.) is aged to obtain even higher conductivity.

Note that the manufacturing conditions of the present invention are specified for the steps after the final solution treatment, and the steps and manufacturing conditions before that may be arbitrary. That is, the method of the present invention does not specify any steps such as solution treatment, hot rolling, intermediate annealing, and cold rolling that are performed before the final solution treatment.

[Example] The present invention will be specifically explained with reference to its implementation.

A copper alloy having the components shown in Table 1 is subjected to final solution treatment to adjust the grain size to the grain size shown in the table, cold rolling after the final solution treatment,
Aging treatment, final cold rolling, and annealing under non-recrystallization conditions were performed in sequence to obtain a 0.20+am plate. The working degrees of the two cold rollings after the final solution treatment were as shown in Table 1.

Regarding these examples, tensile strength, elongation, spring limit value, electrical conductivity, bending workability, corrosion resistance, stress corrosion cracking resistance (hereinafter referred to as S resistance)
CC properties (referred to as CC properties), soldering properties, and heat solder peeling properties were investigated. Tensile strength and elongation were measured using a JIS No. 5 tensile test piece.

The spring limit value was measured by machining the spring into a width of 10mm and a length of 100o+m. The electrical conductivity was measured using a four-terminal method after processing a short piece of 100a+i in width and 100a+i in width. Corrosion resistance is based on JIS H8502, and the sample surface is #1200.
After polishing with sandpaper, 2 at 40℃ and 90%RH.
It was exposed to a 5pIIm SO2 atmosphere for 14 days, and the weight change before and after exposure was measured. This unit indicates corrosion loss (
o+dd: mg/dw'/day).

The SCC resistance was determined by fabricating a test piece with a width of 12.5+am and a length of 150 mm.As shown in Figure 1, this short ff1l was tied into a loop with octopus thread 2, and ammonia water diluted twice with pure water was used. The sample was exposed to a 2051 desiccator containing three samples, and the number of days until cracking occurred was investigated. For soldering, after polishing the sample surface with $1200 merry paper,
ma+width, processed to length of 50III11, exposed to boiling steam for 1 hour, and heated to 800℃ at 230℃ using rosin flags.
It was immersed in 0Sn/40Pb solder for 5 seconds, and its appearance was observed, and a case where 95% or more of the area was covered with solder was evaluated as good. In addition, bending workability was determined by processing a sample to a width of 1011 m, then conducting a 180' bending test according to JIS Z 224B1: and observing the appearance of the bent part. The bending axis was parallel to the rolling direction (bad way), and the inner bending radius was the same as 0.2 mm (plate thickness). The bending workability was judged based on appearance in three stages: good, rough surface, and cracking.

From Table 1, it can be seen that the examples of the present invention have high strength and high conductivity, good bending workability, and other properties as well.

Comparative example No. 13 has a high degree of cold rolling and has a hardness of 180
°Cracks occur during the close bending test. Comparative example No. 1
No. 4 has a large grain size and cracks occur in the 180@bending test. Comparative Examples No. 13 and 14 were both examples in which the manufacturing conditions were inappropriate, and therefore the bending workability was deteriorated compared to the inventive example.

In Comparative Example No. 15, the total concentration of N t s S t SS n is too high, so cracks occur in the 180" bending test. In Comparative Example No. 18, the 5iSSn concentration is lower than the specified value, and aging treatment and cold rolling are not performed. Comparative example No. 17 has an Sn concentration lower than the specified value and has insufficient strength. Comparative example No. 18 has the highest strength in Table 1, but the Ni concentration Solderability is poor because it is higher than the specification.Also, the bending workability is poor because the Ni1S1sSn total concentration is higher than the specification.Comparative example No. 19 is JI
This is S standard nickel silver for springs (C7701R-H). Although it has high strength and good bending workability, it has a lower electrical conductivity than the examples of the present invention. Comparative example No. 20 is JIS standard nickel silver type 2 (
C7521R-H) is a low temperature annealed product. It has high strength and good bending workability, but low electrical conductivity.

On the other hand, the inventive example has strength equal to or higher than that of the comparative example, has higher conductivity than JIS standard nickel silver, and has good other properties such as bendability. be.

[Effects of the Invention] By adopting the manufacturing method of the present invention, it is possible to obtain a high-strength, high-conductivity copper alloy with good bending workability, and it is possible to respond to miniaturization of electronic components and thinning of materials. can.

[Brief explanation of drawings]

FIG. 1 shows a perspective view of the SCC resistance test piece. ■... Short ffi, 2... Octopus thread.

Claims (4)

[Claims] (1) Ni0.4-4.0wt%, Si0.1-1.0
wt%, Sn0.1-3.5wt%, and [wt
%Ni] + [wt%Si] + [wt%Sn]<5.0, in the production of a copper alloy consisting of the balance Cu and unavoidable impurities: (I) Adjusting the grain size to 1 to 10 μm at 700 °C
It is characterized by sequentially performing steps in numerical order, including final solution treatment at a temperature above (II), final cold rolling with a working degree of less than 40% (III), and aging treatment at a temperature of 300 to 700°C. A method for manufacturing a high-strength, high-conductivity copper alloy with good bending workability. (2) Ni0.4-4.0wt%, Si0.1-1.0
wt%, Sn0.1-3.5wt%, and [w
t%Ni]+[wt%Si]+[wt%Sn]<5.0
In the production of a copper alloy consisting of the remainder Cu and unavoidable impurities, (I) adjusting the crystal grain size to 1 to 10 μm at 700°C;
Final solution treatment at the above temperature (II) Working degree immediately after final solution treatment x% (0≦x<40
) Cold rolling (III) Aging treatment at a temperature of 300 to 700°C (IV) Workability Y% (0<{1-(1-X/100)(1-Y/1
00)} x 100 < 40) final cold rolling (V) with good bending workability, characterized in that the steps consisting of heat treatment at a temperature of 150 to 800°C for a period of time without recrystallization are carried out in numerical order. A method for manufacturing a high-strength, high-conductivity copper alloy. (3) Ni0.4-4.0wt%, Si0.1-1.0
wt%, Sn0.1-3.5wt%, and [wt%N
i]+[wt%Si]+[wt%Sn]<5.0, and further contains Fe, Mg, Al, Cr, Mn, Co, as subcomponents.
Contains 0.001 to 2.0 wt% of one or more of Zn, Ti, Zr, Pb, Cd, In, Ag, and P,
In the production of a copper alloy consisting of the balance Cu and unavoidable impurities, (I) Adjusting the crystal grain size to 1 to 10 μm at 700 °C
It is characterized by sequentially performing steps in numerical order, including final solution treatment at a temperature above (II), final cold rolling with a working degree of less than 40% (III), and aging treatment at a temperature of 300 to 700°C. A method for manufacturing a high-strength, high-conductivity copper alloy with good bending workability. (4) Ni0.4-4.0wt%, Si0.1-1.0
wt%, Sn0.1-3.5wt%, and [w
t%Ni]+[wt%Si]+[wt%Sn]<5.0
In addition, as subcomponents Fe, Mg, Al, Cr, Mn, Co, Zn, Ti, Zr, Pb, Cd, I
One or more of n, Ag, and P from 0.001 to
In the production of a copper alloy containing 2.0 wt% and the balance Cu and unavoidable impurities (I) Adjusting the crystal grain size to 1 to 10 μm at 700 ° C.
Final solution treatment at the above temperature (II) Working degree immediately after final solution treatment x% (0≦x<40
) Cold rolling (III) Aging treatment at a temperature of 300 to 700°C (IV) Workability Y% (0<{1-(1-X/100)(1-Y/1
00)} x 100 < 40) final cold rolling (V) with good bending workability, characterized in that the steps consisting of heat treatment at a temperature of 150 to 800°C for a period of time without recrystallization are carried out in numerical order. A method for manufacturing a high-strength, high-conductivity copper alloy.