KR100257204B1 - High strength copper alloy for electric and electric component and method for preparing the same - Google Patents

Abstract

PURPOSE: A method for manufacturing high strength copper alloy for use in electric/electronic components such as connector/terminal is provided to solve problems arising from high Sn content in phosphor bronze. The present invention set the Sn content in phosphor bronze lower so that electric conductivity is increased above 15% IACS. Also, both Ni and Si are added in the copper alloy to compensate strength decline level. CONSTITUTION: The manufacturing method of the high strength copper alloy comprises the processes of preparing an ingot comprising Sn 3.0-6.0wt.%, Ni 0.5-2.0wt.%. Si 0.1-1.0wt.%, Fe 0.5-2.0wt.%, Nd 0.05-0.5wt.%, P 0.01-0.15wt.%, 0.001-2.0wt.% of at least one element selected from Zn, B, Al, Ca, Co, Ti, Zr, Mg, Pd, Mn, REM, a balance of Cu, and other inevitable impurities; quenching the ingot after hot rolling in the temperature range of 700 to 950deg.C; cold rolling in a reduction ratio of 50 to 80% and then heat treating in the temperature range of 300 to 800deg.C for 15-240min wherein above cold rolling and heat treating are performed twice or three times repeatedly; final cold rolling in a reduction ratio of 30 to 60%; and then annealing in the temperature range of 200 to 500deg.C for 0.5-60min.

Description

High strength copper alloy for electric and electronic parts and manufacturing method

The present invention relates to a copper alloy for electrical and electronic parts and a method of manufacturing the same, and more particularly, to improving mechanical properties without lowering the electrical conductivity.

Copper alloys used in leadframe materials for electronic components such as semiconductor ICs, LSIs, and high-strength electrical materials such as connectors, contact springs, relays, contactors, and switches are required to reduce ductility and durability as components are required to be miniaturized, highly integrated, and highly reliable. More excellent heat resistance and electrical conductivity are required.

Copper (Cu) has been widely used as an electrical and electronic material because of its high electrical conductivity and high electrical conductivity. However, copper itself does not provide high strength, so various elements may be added to copper to change the processing process. To obtain.

However, as the number and amount of added elements increase, the conductivity decreases rapidly, and thus the use as an electric and electronic material has been restricted.

Therefore, researches to solve such problems have been conducted in various developed countries, and active research is being conducted to this day.

Representative connectors used in the past include Cu-Sn-based C5210 (Cu-8% Sn-0.1P), which has a tensile strength of 75kgf / mm2, elongation of more than 10%, and electrical conductivity of about 13% IACS.

However, due to the trend of thin and short and high density mounting of electronic devices, products such as connectors and terminals are also required to have narrow pitch, surface mount, and high density. It is becoming.

Representative copper alloys used for connectors and terminals so far include brass (Cu-Zn-based), phosphor bronze (Cu-Sn-P-based), and beryllium copper (Cu-Be-based), but each has problems.

Beryllium copper has the highest strength and hardness among copper alloys, but has the disadvantage of being expensive, easy to oxidize, and difficult to process because of its high hardness.

Although brass is inexpensive and has excellent moldability and workability, it shows excellent characteristics.

Therefore, brass is being reconsidered in terms of reliability, and the demand for phosphor bronze is increasing as a substitute.

Phosphor Bronze has excellent properties in reliability, strength, springability, etc., while it has low electrical conductivity, high tin content, high price, and minimizes segregation of tin during solidification. There are problems such as being strictly controlled.

Recently, a number of new alloys have been developed, but they are suitable only for special applications or include manufacturing difficulties, and in addition, economically practical materials are extremely rare.

On the other hand, Japanese Patent Publication Nos. 60-45698 have Ni, Si, Cu as main components, and 14 kinds of Sn, Fe, etc. as sub-components as lead materials for semiconductor devices, but Sn is 1.0% or less. In addition, the tensile strength is almost 70kg / mm2 or less.

The present invention has been made to solve the problem of phosphor bronze material is expected to continue to increase in the future, by setting the tin (Sn) content to improve the electrical conductivity to 15% IACS or more, so that hot rolling It was designed to omit the homogenization process, and the addition of Ni and Si prevented the decrease in strength due to the reduction of Sn addition amount, and the tensile strength by adding Fe, which is used as a deoxidizer, to form a compound. It was possible to maintain more than 75kgf / ㎜.

In addition, by adding Nd, the addition of Ni, Si, Fe, P and fine precipitates to form, and to act as a grain growth inhibiting effect to provide a high-strength alloy with improved tensile sensitivity and elongation and its manufacturing method.

As the weight% of the present invention for achieving the above object, Sn: 3.0 to 6.0%, Ni: 0.5 to 2.0%, Si: 0.1 to 1.0%, Fe: 0.5 to 2.0t%, Nd: 0.05 to 0.5%, P: 0.01 to 0.15%, and the rest consists of an alloy composition containing Cu and unavoidable impurities.

In addition, the present invention can add 0.001 to 2.0% by weight of one or two or more selected from Zn, B, Al, Ag, Ca, Co, Ti, Zr, Mg, Pb, Mn, and REM in addition to the above components. It may be.

Sn in the composition is an element that is dissolved in the matrix to improve the tensile strength and elastic limit.

If the content of Sn is less than 3.0% by weight, high strength (75kgf / mm2) characteristics can not be obtained, whereas if the content of more than 6.0% by weight, the electrical conductivity is reduced to 15% IACs or less, and hot brittleness occurs, making hot rolling difficult.

Therefore, the content of Sn should be 3.0 to 6.0% by weight.

Ni is an element that combines with Si to form an intermetallic compound such as Ni ₂ Si and P to form an intermetallic compound such as Ni ₃ P to improve strength and heat resistance without reducing electrical conductivity.

If the Ni content is less than 0.5% by weight does not show the effect of improving the strength, when the Ni content is more than 2.0% by weight is uneconomical because the precipitation strengthening effect of the addition amount is reduced.

Therefore the Ni content should be 0.5 to 2.0% by weight.

If the Si content is less than 0.1% by weight, there is no improvement in strength and heat resistance even if Ni is contained in 0.5 to 2.0% by weight. If it is 1.0% by weight or more, the amount that can be precipitated exceeds the amount that can be precipitated, and thus exists as a solid solution in the base. Decreases.

Therefore, Si content should be 0.1 to 1.0 weight%.

Fe is an element that is dissolved in the base and improves strength.

In addition, Fe forms an intermetallic compound, such as Fe ₃ P or Fe ₂ P, by combining with residual P which is not bonded with Ni, thereby improving strength and heat resistance without reducing conductivity.

If the Fe content is less than 0.5% by weight almost no additive effect, while the content of more than 2.0% by weight significantly reduces the electrical conductivity.

Therefore, the content of Fe should be 0.5 to 2.0% by weight.

If the P content is less than 0.01% by weight, even if it contains 0.5 to 2.0% by weight of Fe and 0.5 to 2.0% by weight of Ni, there is no improvement in strength and heat resistance, and the electrical conductivity is reduced by the excess Fe and Ni.

If the P content exceeds 0.15% by weight, the electrical conductivity is sharply reduced and the hot workability is lowered.

Therefore, the content of P should be 0.01 to 0.1% by weight.

If the Nd content is less than 0.05% by weight, there is no improvement effect in improving the strength and elongation. If the Nd content is more than 0.5% by weight, the oxidation of the molten metal is severe, causing defects in the ingot and reducing electrical conductivity.

Therefore, Nd content should be 0.05 to 0.5 weight%.

As a subcomponent additionally added to the main component, at least one of Zn, B, Al, Ag, Ca, Co, Ti, Zr, Mg, Pb, Mn, and REM is 0.001 to 2.0 wt%, and 0.001 wt% If it is% or less, a high strength and corrosion resistant alloy cannot be obtained, and when it exceeds 2.0 weight%, there exists a possibility of the fall of electroconductivity.

Moreover, in this manufacturing method of this invention, it melt | dissolves so that it may become the said alloy composition, and an ingot is obtained.

The ingot is hot rolled at 700 to 950 ° C. and then quenched to solution treatment. Cold rolling is performed at 50 to 80%, followed by heat treatment at 300 to 800 ° C. for 15 minutes to 4 hours. After repeated 2 to 3 times, the final cold rolling at a reduction ratio of 30 to 60%, and an annealing treatment for 30 seconds to 1 hour at a temperature of 200 ~ 500 ℃.

In the above process, hot rolling is intended for solution treatment and thickness reduction, and for the formation of precipitates, the formation of precipitates is lowered above 950 ° C. and below 700 ° C., so that an appropriate temperature range is 700 to 950 ° C.

The hot rolling is followed by a quenching treatment (solution treatment: treatment of obtaining a homogeneous structure even at room temperature by quenching the high temperature structure).

In the treatment, cold rolling is performed by applying a reduction ratio of 50 to 80%, followed by annealing heat treatment at 300 to 800 ° C. for 15 minutes to 4 hours. The cold rolling and annealing heat treatment are repeated two to three times.

The cold working rate (pressure reduction rate) has a close relationship with the heat treatment temperature, and the high working rate promotes homogenization of the entire structure and formation of precipitates during heat treatment.

The increase in electrical conductivity due to the promotion of precipitate formation during annealing by cold working is greater than the decrease in electrical conductivity actually reduced by cold working, and at the same time, the strength and hardness are improved.

The amount of precipitates that are densely distributed on the slip band due to cold rolling increases as the amount of cold working before annealing increases, so that the optimum annealing temperature is 300 to 80% after the first cold working. 800 ° C.

When the annealing temperature exceeds 800 ℃, it has a direct effect on the strength. At high temperatures, the electrical conductivity decreases. On the other hand, when the annealing temperature is lower than 300 ℃, the formation of precipitates by high processing proceeds considerably later. There is no industrial economics.

Since the cold working rate and the heat treatment temperature have a close relationship, the above-mentioned action is increased by repeating the cold working and heat treatment.

When the heat treatment time is less than 15 minutes, the formation of precipitates is unstable, and when more than 4 hours, the electrical conductivity may be reduced.

Following the treatment, final cold rolling at a processing rate of 30 to 60% to obtain the required thickness is followed by annealing at 200 to 500 ° C. for 30 seconds to 1 hour.

In the annealing (aging treatment) step according to the miniaturization of the cold rolled structure, hardening occurs due to the appearance of sufficient precipitated phase, so that the required hardness can be obtained. If the temperature and time range are exceeded, the required characteristics cannot be obtained. .

According to the above manufacturing process, the material of the present invention exhibits an electric conductivity of IACS of 15% or more, a tensile strength of 73 to 79 kg / mm2, and an elongation of 10.6 to 14.2%, thereby being very suitable for electric and electronic parts, especially connectors and terminals. It is shown.

The following is described according to the embodiment.

The alloy of the composition shown in Table 1 is melt | dissolved in air | atmosphere under charcoal coating, and then inject | poured into a graphite mold at 1200-1300 degreeC, and obtain 50 mmT x 50 mmW x 130 mmL ingot.

The four sides of the ingot were faced 2 mm each, heated at 700 to 950 ° C. for 1 to 4 hours, followed by hot rolling and quenching.

After removing the oxide scale of the surface by surface, cold rolling, intermediate heat treatment, and surface pickling were repeated to prepare 0.2-0.3 mm thick specimens.

Cold rolling was carried out at 50% or more, and the intermediate heat treatment was performed at 300 to 800 ° C. for 15 to 240 minutes, and the scale of oxide formed on the surface after heat treatment was removed with dilute sulfuric acid.

After the final cold rolling, low temperature annealing was performed at 200 to 500 ° C. for 30 seconds to 60 minutes to improve elongation.

Table 2 shows the test results of the specimen thus obtained.

In the test method used, the tensile strength and elongation were measured using a specimen cut parallel to the rolling direction, the electrical conductivity was converted into% IACS by the resistance method, and the hardness was 500g using a micro-Vickers hardness tester. Was measured for 15 seconds.

In addition, the softening temperature was evaluated by heating the specimen for 5 minutes for each temperature section and measuring the temperature indicating 80% of the initial hardness. The adhesion of the plating layer was tested by observing the plating surface to see if swelling or peeling of the plating occurred.

As described above, in order to solve the problem of the conventional phosphor bronze material, the tin (Sn) content is set low, and Ni, Si, P, Fe, Nd elements, etc. are added as appropriately adjusted and added through the manufacturing process. It is possible to obtain a material having properties suitable for electric and electronic component materials, preferably connectors and terminals, having hardness, particularly high strength, including conductivity enhancement.

Claims (2)

As the weight%, Sn: 3.0 to 6.0%, Ni: 0.5 to 2.0%, Si: 0.1 to 1.0%, Fe: 0.5 to 2.0%, Nd: 0.05 to 0.5%, P: 0.01 to 0.15%, Zn, B, Al, Ca, Co, Ti, Zr, Mg, Pd, Mn, REM is one or more selected from 0.01 to 2.0% of the high strength copper alloy for electric and electronic parts, characterized in that the composition is composed of Cu and unavoidable impurities. As the weight%, Sn: 3.0 to 6.0%, Ni: 0.5 to 2.0%, Si: 0.1 to 1.0%, Fe: 0.5 to 2.0%, Nd: 0.05 to 0.5%, P: 0.01 to 0.15%, Zn, B, At least one selected from Al, Ca, Co, Ti, Zr, Mg, Pd, Mn, and REM or 0.001 to 2.0%, and the remainder is dissolved in a composition composed of Cu and unavoidable impurities to obtain an ingot. Hot rolling at 700 to 950 ° C., followed by quenching, cold rolling at 50 to 80%, and heat treatment at 300 to 800 ° C. for 15 minutes to 4 hours, wherein the cold rolling and heat treatment are performed two to three times. Repeatedly carried out over, applying a reduction ratio of 30 to 60%, annealing for 30 seconds to 1 hour at 200 to 500 ℃ after the final cold rolling, characterized in that the manufacturing method of high-strength copper alloy for electrical and electronic parts .