JPS60121245A - Copper alloy for terminal or connector and its manufacture - Google Patents

Abstract

PURPOSE:To obtain the titled alloy having superior tensile strength and a high elastic limit value while eliminating the defects and problems of two kinds of phosphor bronze or phosphor bronze for a spring by specifying the amounts of Sn and P contained in Cu and adding a prescribed amount of Fe or Co. CONSTITUTION:This Cu alloy for a terminal or a connector consists of, by weight, 3.0-6.5% Sn, 0.025-0.045% P, 0.05-0.15% Fe and/or Co and the balance Cu. A Cu alloy ingot having said composition is hot rolled at >=about 80% draft and cooled from >=about 600 deg.C to <=about 350 deg.C at >=about 25 deg.C/min cooling rate. The alloy is cold rolled at >=about 80% draft, annealed at 350-550 deg.C for about 5-180min, and finish-rolled according to the use. The alloy is then subjected to tension annealing at about 200-500 deg.C for about 5-60sec to relieve the local stress. Lonnealing may be carried out at about 200-500 deg.C for about 30-180min before the tension annealing. Thus, the desired alloy is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copper alloy for terminals and connectors and a method for manufacturing the same.

High-grade materials for terminals and connectors include phosphor bronze type 2 and type 3.
In addition, phosphor bronze for springs is used, which is obtained by annealing three types of phosphor bronze at low temperatures. However, as shown in the Japanese Industrial Standards, phosphor bronze has a content of 3.0 d% or more, 9. Ou+t% or less of Sn is contained, and when the Sn content increases, Sn tends to segregate in the surface layer and grain boundaries in the ingot formation method by continuous casting of ordinary copper alloys, and this segregation must be removed. The surface layer of the ingot may melt during heating during hot rolling. In addition, two types of commercially available phosphor bronzes or phosphor bronzes for springs contain 0.1 to 0 to 21% of P, and in ordinary agglomeration methods, Cu with a melting point of 714°C is mixed with a segregated layer of So. Since a eutectic of Cu and Cu 3P tends to form, hot workability becomes even more difficult. And this eutectic is S
Like n, it is distributed not only on the ingot surface but also within the ingot and at grain boundaries. Therefore, surface milling and long-term homogenization treatment at a temperature of 714° C. or lower are required to eliminate the Sn segregation layer and the eutectic of Cu and Cu3P.

The present invention was made in view of the drawbacks and problems of the above-mentioned two types of phosphor bronze or phosphor bronze for springs, and provides a copper alloy for terminals and connectors with excellent tensile strength, spring limit value, etc., and a method for manufacturing the same. It is something to do.

The copper alloy for terminals and connectors and the manufacturing method thereof according to the present invention include (1) Sn 3.0 to 6.5u+f%, PO,
025 to 0.0451%, 0.05 to 0.15% of one or both of Fe, 4, and Co, and the remainder substantially consists of Cu. As the first invention, (2) Sn 3.0 to 6.5 den L
%, PO,025-0,,045u+t%, a copper alloy ingot containing 0.05 to 0.15u+L% of one or both of Fe or Co, and the remainder being substantially Cu, was processed at a processing rate of 80 From a temperature of 600'C or more after hot rolling of 2% or more
Cooling to a temperature of 350°C at a cooling rate of 5°C/min or more, and further cold rolling at a processing rate of 80% or more, 35
After annealing for 5 to 180 minutes at a temperature of 0 to 550°C, finish rolling for temper adjustment was performed, and then 2 (10
Low-temperature annealing for 30-180 minutes at a temperature of ~500°C or 1 hour, 5 minutes at a temperature of 200-500°C.
This invention consists of two inventions, the second invention being a method for producing a copper alloy for terminals and connectors, which is characterized by performing tension annealing for local stress relief for ~60 seconds.

To briefly explain the features of the copper alloy for terminals and connectors and the manufacturing method thereof according to the present invention, the Sn content is 1) lower than that of phosphor bronze for springs, which is 6,5%... Reduces the amount of Sn segregation during agglomeration,
In addition, by keeping the P content as low as 0.025 to 0.045 L%, the amount of Cu and eutectic such as P can be reduced and an ingot that can be hot rolled can be cast. .

0.05-0.15 of one or both of Fe or CO
The reason why Fe or Co is contained at 1% is because it forms phosphides and precipitates, making the crystal grains finer and strengthening the matrix, and P is essential for deoxidizing the molten metal, but the content is small. If not, the precipitated amount of Fe or CO phosphide necessary for strengthening the matrix will be insufficient, and if it is too large, it will remain in the matrix and reduce the electrical conductivity.

Furthermore, it is essential to dissolve Fe, Co, and P into the Cu matrix after hot rolling the copper alloy # ingot having the components and proportions explained in Section 2. ] It is necessary to perform forced cooling from a temperature of 0°C, and if this cooling rate is slow, Fe or Co phosphides will form in the hot state, reducing their contribution to alloy strengthening in the final product. After the completion of hot rolling, it must be cooled to 35 C1'C or less at a cooling rate of 25 C/min or more. cold open rolling with a processing rate of at least 80% to make the distribution of dislocations uniform, and then
By annealing for 5 to 180 minutes at a temperature of C,
Phosphides of Fe or Co are formed.

The generated phosphide has a tendency to have destructive properties such as tensile strength and spring limit value, but contains an additional 2ul% of So.
The improvement in effectiveness is seen to be equivalent to that of

Next, the copper alloy for terminals and connectors and the manufacturing method thereof according to the present invention will be explained in more detail.

First, the components and component ratios of the copper alloy for terminals and connectors according to the present invention will be specifically explained.

It is an element that improves tensile strength, spring limit value, and moldability by solid solution in 5nl Cu, and the content is 3. If it is less than O
It was not possible to obtain the same properties as the two types of phosphor bronze containing 5.5u+L% of
The same properties as Sn (7.0 to 9.01%) can be obtained, and from the viewpoint of hot rolling, the inclusion of this amount is not necessary. Therefore, the Sn content is set to 3.0 to 6.5 wt%.

When Fe and Co coexist with P, they form phosphides, improving tensile strength and spring limit value.
Even if P is contained in an amount exceeding 0.15u+t%, no precipitates are formed that are sufficient to improve the tensile strength and spring limit values, and if P is contained in an amount exceeding 0.15u+L%,
25-0,045u+L% Fe, Co
is dissolved in the matrix and reduces the conductivity. Therefore, Fe
Or, the content of one or two types of Co is 0.05 to 0.
It will be 151%.

P is Fe or C if the content is less than 0.025u+t%
.

Even if 0.05-0.15u+L% of one type or 2N is contained, no improvement in tensile strength or spring limit value can be expected, and if it is contained in excess of 0.045u+t%. One or both of Fe or Co is 0.05-0.1
700-8 of the ingot obtained even if it contains 5u+t%
Hot open rolling properties at a temperature of 00°C deteriorate.

Therefore, the P content is set to 0.025-0.045+uL%.

Next, a method for producing a copper alloy for terminals and connectors according to the present invention will be explained in detail.

The reason for hot rolling an ingot of copper alloy for terminals and connectors with the above-mentioned ingredients and ratios at a processing rate of 80% or more is to completely destroy the cast structure and eliminate the effects of segregation in the ingot. It is.

The reason for cooling from a temperature of 600°C or more after hot rolling to a temperature of 350°C or less at a cooling rate of 25°C/min or more is to dissolve phosphide into the matrix after hot working. If the cooling start temperature is less than 600°C, phosphides will precipitate, and even when cooling from a temperature of 6QO°C or higher, if the cooling rate is slower than 25°C/min, phosphides will precipitate during the cooling process. That is, the phosphide present in the state after hot working is
Even when the subsequent cold-opening and annealing are performed, the precipitates are not consistent with the matrix and do not contribute to improving the tensile strength and spring limit value.

Also, the cooling end temperature is sufficient at 350°C, and 350°C is sufficient.
Phosphides are difficult to form even if the temperature is kept below °C.

Furthermore, performing cold rolling at a processing rate of 80% or higher is the processing rate necessary to uniformly distribute dislocations in the matrix, and the subsequent annealing produces uniform and fine particles according to the dislocation distribution. This cold working rate is important because it can precipitate phosphides.

5 at a temperature of 350-550°C after this cold rolling.
The reason for performing annealing for ~180 minutes is that at temperatures below 350°C, phosphides, which contribute to tensile strength, will not precipitate even if annealing is performed for more than 180 minutes, and at temperatures above 550°C, Cu-5n will not precipitate. This is because the solid solubility limits of Fe, Co, and P in the steel become large, so fewer phosphides precipitate, and it is no longer possible to expect an improvement in tensile strength and spring limit value by increasing the Sn content by 2u+t%. However, if the annealing time is less than 5 minutes, equilibrium will not be reached yet and the properties will become unstable.
Further, annealing for a time exceeding 180 minutes is wasteful because the target characteristics are sufficiently obtained with an annealing time of 180 minutes.

After this annealing, temper adjustment is performed, that is, after temper finish rolling, tension annealing is performed at a temperature of 200 to 500°C for 5 to 60 seconds in order to remove local stress and obtain a smooth strip or plate. If the temperature is below 500"C, you will not be able to obtain a flat plate even if you hold it for 60 seconds, and if the temperature exceeds 500"
Even if held for seconds, it is difficult to stably obtain the target tensile strength and spring limit value. If the holding time is less than 5 seconds, problems such as differences in mechanical properties at the ends and center of the coil will occur, and if it exceeds 60 seconds, productivity will be significantly impaired.

However, when the final finishing rate exceeds 70%, a high spring limit value cannot be obtained with short-time annealing within 60 seconds, which is possible with high-speed mass production equipment such as tension annealing, and the spring limit value is 200~200%. By annealing in a batch furnace with a coil of 7 ohm for 30-180 minutes at a temperature of 500 °C.
It is preferable to perform the above-mentioned tension annealing after the target spring limit value is obtained.

Examples of the copper alloy for terminals and connectors and the manufacturing method thereof according to the present invention will be described, and comparative examples will also be described.

EXAMPLE Electrolytic copper was melted at a temperature of about 1200'C under charcoal coating by cryptoluminization to obtain a copper alloy having the components and proportions shown in Table 1, and a strip of F(!, Co) was melted. After confirming that these have penetrated, the remaining 30
% electrolytic copper and set the molten metal temperature to 1160-1170°.
The temperature was lowered to C, an intermediate alloy of Sn and Cu-15iut%P was added, stirred thoroughly, and after settling, a cast iron mold was poured into a cast iron book mold mold by the tilting method.

The ingot is 60. . Tl1tX 60mmL'X 14 O
r. ,. It is the size of .

No. 1 to No. 5 of the present invention in Table 1 and comparative example (N
o, 8, No., 10 and 11) total of 5m on both sides
After milling, it is heated to a temperature of 800°C, hot rolled to a thickness of 1.5+nm, cooled in water from a temperature of 650°C, and then cold rolled to a thickness of 0.50 to 1.0 years. 500°C
Annealing was carried out at a temperature of 120 minutes, and cold-open rolling was then carried out to produce a plate material with a thickness of 0.4 Onon.

Among Comparative Examples No. 8.10 and 11, No.

No. 8 had cracks during hot rolling at 750°C, so further processing was discontinued, while Nos. 10 and 11 were subjected to solution treatment at 700°C for 5 hours in order to compare their properties. , cold rolling with a processing rate of about 60% and 450
Intermediate annealing was repeatedly performed for 2 hours at a temperature of .degree. C. to produce a plate material having a thickness of 0.40 mm and having approximately the same tensile strength as the present invention. The tensile strength was 65 Kgf/+n)2.

Present invention No. 1- No. 5 and comparative example No. 6.7
and for 9, the tension 10 K gf/nun
2 was added and annealing was performed at a temperature of 350° C. for 20 seconds. 250°C for Comparative Examples No. 10 and 11
Annealing was performed at a temperature of 2 hours. The results are shown in Table 2. In each case, test pieces parallel to the rolling direction were prepared and their properties were measured. Note that the 90° bending process was performed using a 30 ton refreshing press at a speed of 3005 pans.

As is clear from Tables 1 and 2, the present invention No.
1.2 and 3 are comparative example Nos. containing 21% more Sn
, 10, and invention Nos. 4 and 5 have Sn as 2Illt.
% higher than Comparative Example No. 11, the copper alloy for terminals and connectors according to the present invention is equivalent or better in all properties of tensile strength, spring limit value, electrical conductivity, and bending test. It is shown. It can be seen that elongation is a guideline for workability, but it is only a reference value.

Moreover, as shown in Table 2, when the present invention No. 1 and the comparative example Nos. 6.7 and 9 are compared, Fe.

It has been demonstrated that when Co and P deviate from the content ratios of the copper alloy for terminals and connectors according to the present invention, elongation, spring limit value, and bending workability are reduced.

Separately, the hot-rolled material of the present invention No. 1 has a thickness of 15+nm.
A sample was prepared by a comparative processing method in which a section was cut out, placed in a furnace where the cooling rate could be controlled at 10°C/min, and cooled from 650°C to 300°C. The thickness of this sample is 0, 4
The processing method up to mm is as described above, and the obtained results are shown in Table 3.

Table 3 As explained above, the copper alloy for terminals and connectors according to the present invention and the method for producing the same have the above-mentioned structure.
It is clear that this is a copper alloy consisting of +t% less contained components and component ratios, and has properties equal to or better than those of these two phosphor bronzes.

Claims (2)

[Claims] (1) Sn 3.0-6.5u+t%, PO,02
5-0.045u+t%, 0.05-0.15u+L% of one or both of Fe or Co, and the remainder substantially consisting of Cu. (2) Sn 3.0-6.5wL%, PO,025
-0,045+ut%, one or two of Fe or Co
Contains 0.05-0.15u+L% of seeds and the remainder is substantially C
After hot rolling a copper alloy ingot with a processing rate of 80% or more, the ingot is cooled from a temperature of 600'C or more to a temperature of 350'C or less at a cooling rate of 25°C/min or more, and further, 350-550
After annealing at a temperature of 5 to 180 minutes, finishing rolling for temper adjustment is performed, and then 200 to 180 minutes of annealing is carried out.
With or without low-temperature annealing for 3() to 180 minutes at a temperature of 200 to 500'C.
A method for producing copper alloys for terminals and connectors, characterized by carrying out tension annealing to remove local stress for 60 seconds.