JP2001049367A - High strength, high conductivity and high heat resistance copper base alloy and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a copper base alloy maintaining electric conductivity, tensile strength and Vickers hardness equal to or above the specified value even after heating at a specified temp. for a specified time by producing it by using an ingot of a copper base alloy contg. specified rations of iron, phosphorus and zinc. SOLUTION: This high strength, high conductivity and high heat resistance copper base alloy is produced by using an ingot of a copper base alloy contg., by weight, 2.0 to 2.5% iron, 0.01 to 0.2% phosphorus and 0.01 to 1% zinc, has >=70% IACS electric conductivity and >=520 N/mm2 tensile strength and maintains the value of >=90% of Vickers hardness of >=155 Hv even after heating at 450 deg.C for 5 min. An ingot of a copper base alloy is hot-rolled at 800 to 1,050 deg.C, is thereafter cold-rolled, is held at >=900 deg.C for >=30 sec and is immediately cooled to 500 deg.C at a cooling rate of >=100 deg.C/min. After that, it is cold-rolled, is annealed at 550 to 650 deg.C for 30 min to 6 hr, is moreover annealed at 400 to 525 deg.C for 1 to 10 hr and is cold-rolled so as to control the finish rolling working ratio to 70 to 85% to obtain a copper base alloy suitable for a lead frame material or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper-based alloy and a method for producing the same, and more particularly, to a copper-based alloy having high strength, high electrical conductivity and high heat resistance by improving a heat treatment process, and a method for producing the same.

[0002]

2. Description of the Related Art Electricity represented by lead frame materials, etc.
Electronic component materials are required to have various properties such as high strength, high electrical conductivity, and high heat resistance. To meet such demands, iron (Fe) 1.5 to 3.5%, phosphorus (P) 0.01 to 0.15%, zinc (Zn) 0.03 to
As a method of manufacturing a material such as an electronic component by processing a copper-based alloy containing 0.2% and a balance of copper (Cu) and unavoidable impurities, for example, Japanese Patent Publication Nos. 52-20404 and 55-55 No. 14,132, Japanese Patent Publication No. 55-14133, Japanese Patent Publication No. 55-14134, Japanese Patent Publication No. 3-44141, and Japanese Patent Publication No. 6-11904. These production methods are intended to impart suitable performance to materials of electric / electronic parts by increasing the workability of a Cu-Fe-based alloy, and conductance, tensile strength,
In terms of strength such as Vickers hardness, suitable performance can be provided.

However, in these manufacturing methods, heat resistance or softening point, which is one of the important properties required for materials of electric / electronic parts, is not particularly mentioned, and Cu-F
Simply increasing the workability of the e-based alloy was not always sufficient in terms of heat resistance.
In particular, in applications of lead frame materials, high strength is required due to the progress of increasing the number of pins and thinning. Further, in actual use, for example, in many cases, high-temperature heat treatment is performed such as heating at a temperature of 400 ° C. or more in a distortion removing step at the time of stamping, so that the strength of the material can be maintained even after high-temperature heating. It is required to be something.

[0004] On the other hand, a production method in which magnesium (Mg) is added in addition to the composition of the above-mentioned various elements to impart suitable performance with respect to heat resistance or softening point is disclosed in, for example, Japanese Patent Publication No. 64-449. It has been disclosed.

[0005]

[Problems to be solved by the invention]
According to the production method disclosed in Japanese Patent No. 449, since magnesium (Mg) must be additionally added,
The number of added elements increases, the number of control items increases, and the cost increases.

Accordingly, an object of the present invention is to improve not only the heat treatment step without adding other elements, but to obtain not only high strength and high conductivity but also high heat resistance. An object of the present invention is to provide a copper-based alloy capable of maintaining high strength even after high-temperature heating to be performed and a method for producing the same.

[0007]

SUMMARY OF THE INVENTION The present invention provides the following high-strength, high-conductivity, high-heat-resistant copper-based alloys and a method for producing the same.

[1] Iron (Fe) 2.0-2.5% by weight, phosphorus (P) 0.01-0.2% by weight, zinc (Zn)
Manufactured from an ingot of a copper-based alloy containing 0.01 to 1% by weight and having a conductivity of 70% IACS or more, 520 N / mm ²
Having a tensile strength of not less than, and Vickers hardness of not less than 155 Hv, even after being heated at 450 ° C. for 5 minutes, the electrical conductivity, the tensile strength, and a value of not less than 90% of the Vickers hardness are maintained. A high-strength, high-conductivity, high-heat-resistant copper-based alloy characterized by maintaining.

[2] Copper (Cu) as a main component, iron (Fe) 2.0 to 2.5% by weight, phosphorus (P) 0.01 to
An ingot of a copper-based alloy containing 0.2% by weight and zinc (Zn) of 0.01 to 1% by weight is hot-rolled at 800 to 1050 ° C, then cold-rolled, and heated to 900 ° C or more. And immediately cooled to 500 ° C. at a cooling rate of 100 ° C. or more per minute, further cooled to room temperature, and then cold-rolled, at a temperature of 550 to 650 ° C. for 30 minutes to 6 hours. Annealing, further annealing at a temperature of 400 to 525 ° C for 1 to 10 hours, and cold rolling at a finish rolling degree of 70 to 85%, characterized by high strength, high conductivity and high heat resistance copper base. Alloy manufacturing method.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a high-strength, high-conductivity, high-heat-resistant copper-based alloy according to the present invention and a method for producing the same will be described in detail. According to the present invention, a copper-based alloy ingot containing a specific component described below is subjected to a specific heat treatment described below.

1. Copper-based alloy ingot (1) Copper-based alloy component Hereinafter, each component will be specifically described.

(I) Iron (Fe) Component The iron (Fe) content of the copper-based alloy in the present invention is as follows:
The content is preferably in the range of 2.0 to 2.5% by weight, and more preferably 2.1 to 2.3% by weight. Iron (F
e) has an effect of improving strength and heat resistance mainly by precipitating in copper (Cu), but if it is less than 2.0% by weight, the amount of iron (Fe) precipitated is insufficient. The strength and heat resistance cannot be obtained. On the other hand, when the content exceeds 2.5% by weight, the decrease in conductivity is large and coarse iron (F
If the crystallized product of e) is generated and remains in the product, it may be a starting point of bending cracking or cause plating failure.

(Ii) Phosphorus (P) component The content of the phosphorus (P) component of the copper-based alloy in the present invention is as follows:
It is preferably in the range of 0.01 to 0.2% by weight, more preferably 0.01 to 0.05% by weight. Phosphorus (P) has an action of deoxidizing oxygen mixed in the molten metal during the melt casting, but if it is less than 0.01% by weight, the effect is not sufficient to obtain the effect. If it exceeds 0.1% by weight, although the deoxidizing effect tends to be saturated, it combines with iron (Fe) to form a precipitate, and this precipitate contributes to improvement in strength and heat resistance. On the other hand, if the content exceeds 0.2%, such an effect is not only saturated, but also the compound of phosphorus (P) and iron (Fe) precipitated at the crystal grain boundary or the like at the time of core cracking or hot rolling. This causes grain boundary cracking, and the adverse effect becomes large.

(Iii) Zinc (Zn) component The zinc (Zn) component content of the copper-based alloy in the present invention is as follows:
It is preferably in the range of 0.01 to 1% by weight, more preferably 0.05 to 0.15% by weight. Zinc (Zn) improves solder wettability and has a deoxidizing and degassing effect and an effect of suppressing migration of copper (Cu). However, if it is less than 0.01% by weight, it is not sufficient to obtain the effect. . On the other hand, when it exceeds 1.0% by weight, the conductivity is lowered.

(Iv) Other elemental components The base alloy of the present invention basically contains copper (Cu) as a main component and contains specific amounts of iron (Fe), phosphorus (P), and zinc (Zn). Which is not intended to add another element. However, it is sometimes unavoidable to mix other elements as impurities, so that Mg, Al, Si, T
If at least one of i, Cr, Mn, Co, Ni and Sn is contained in an amount of 0.2% by weight or less, it may be contained as an unavoidable impurity component.

(2) Ingot The ingot of the copper-based alloy used in the present invention can be ingot by, for example, an ordinary copper alloy continuous casting method or semi-continuous casting method. In the cooling process at this time, iron (Fe) precipitates, but since these have a bad influence on hot workability,
It is preferred that these iron (Fe) precipitates be solid-dissolved before the subsequent hot rolling.

2. Heat treatment (1) First hot rolling and cold rolling In the present invention, the copper-based alloy is hot-rolled at a temperature of 800 to 1050C. If the temperature is lower than 800 ° C., iron (F
The precipitation amount of e) is large, and cracks easily occur during hot rolling.
Next, cold rolling is performed. In order to increase the heat exchange rate during the subsequent solution treatment, it is preferable to set the sheet reduction rate so that the sheet thickness becomes 3 mm or less.

(2) Solution treatment After the hot rolling and the cold rolling, the solution is treated at a temperature of 900 ° C. or more for 30 minutes.
After holding for more than a second, immediately cool to 500 ° C. at a cooling rate of 100 ° C. or more per minute and further cool to room temperature (hereinafter, referred to as
"Solution treatment"). Hereinafter, a specific description will be given.

This solution treatment is performed to re-solidify iron (Fe) precipitates precipitated during hot rolling.

In the present invention, the solution treatment is performed at a heating temperature of 900.
Perform at or above ° C. Since the solid solubility of iron (Fe) in copper (Cu) increases as the temperature increases, the higher the holding temperature, the better from the viewpoint of heat resistance. If it is lower than 900 ° C., the amount of solid solution will be insufficient. The target heat resistance cannot be obtained.

In the present invention, the solution treatment is performed for a holding time of 30 seconds or more. The diffusion rate of iron (Fe) in copper (Cu) is high. At 900 ° C. or higher, solid solution can be achieved once again by holding for about 30 seconds. Can be.

Further, in the present invention, the solution treatment is rapidly cooled to 500 ° C. immediately after the elapse of the holding time at a cooling rate of 100 ° C. or more per minute, and further cooled to room temperature.

From the viewpoint of imparting heat resistance, it is necessary to cool at a rate such that iron (Fe) precipitates precipitated during the cooling process do not become coarse. Since the diffusion rate is high, if cooling is performed at a cooling rate lower than 100 ° C. per minute up to 500 ° C., iron (Fe) precipitates become coarse and the target heat resistance cannot be obtained. If the temperature is lower than 500 ° C., the rate of precipitation of iron (Fe) becomes slow. Therefore, it is not necessary to increase the cooling rate. A cooling rate of about 5 ° C./minute or more to room temperature is sufficient.

(3) Second Cold Rolling and Purification After the solution treatment, cold rolling is carried out at 550-650 ° C.
Anneal for 30 minutes to 6 hours at a temperature of 400 to 52
Anneal at a temperature of 5 ° C. for 1 to 10 hours. The cold rolling is preferably performed so that the area reduction rate is 50% or more. As a result, it is possible to make precipitation by annealing described below smooth.

In the present invention, refining is performed in two stages. If only one stage of refining is used, the heat resistance becomes insufficient.

First, the first annealing is performed at a temperature of 550 to 650 ° C. for 30 minutes to 6 hours. If the initial annealing temperature exceeds 650 ° C. or less than 550 ° C., iron (Fe) precipitates cannot be deposited to an appropriate size, and the desired heat resistance and strength cannot be obtained. The annealing time is 30
If less than minutes or more than 6 hours, the desired heat resistance and strength cannot be obtained.

Next, a second annealing is performed at a temperature of 400 to 525 ° C. for 1 to 8 hours. At a temperature lower than 400 ° C., a long time is required for precipitation, and at a temperature higher than 525 ° C., the target heat resistance cannot be obtained.

As long as the second annealing is in the range of 400 to 525 ° C., multi-stage aging with a plurality of aging temperatures may be used. In addition, the second annealing may be performed following the first annealing, or may be performed after the temperature is once lowered to room temperature.
The cooling rate is not particularly limited, but is preferably 1 ° C. or more per minute. In addition, between the first annealing and the second annealing, processing with a surface reduction rate of 30% or less may be performed.

The furnace is not particularly limited, but is preferably a batch type furnace.

(4) Third Cold Rolling After the cold rolling and sintering, finish rolling is performed at a finish rolling degree of 70.
Perform at ~ 85%. If it is less than 70%, the strength such as tensile strength and Vickers hardness becomes insufficient. On the other hand, if it exceeds 85%, the heat resistance becomes insufficient. Further, after this, low-temperature annealing for improving elongation and removing strain may be performed.

[0031]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited by these examples.

Example 1 2.2% by weight of iron (Fe)
A copper (Cu) alloy containing 0.03% by weight of phosphorus (P) and 0.01% by weight of zinc (Zn) is melted in a high-frequency induction crucible furnace, and then semi-continuously cast in a copper mold to obtain a cross section of 200 m.
A rectangular parallelepiped ingot having a size of mx 450 mm and a length of 4000 mm was produced. The surface of the ingot was cut 5 mm each,
After holding at 0 ° C. for 2 hours, hot rolling was performed to obtain a sheet thickness of 12 mm. Furthermore, after the front and back surfaces are each 1 mm sharpened,
The thickness was reduced to 2.5 mm by cold rolling. Next, in a continuous annealing furnace, the material is passed through a heating zone at an ambient temperature of 930 ° C. at a speed of 2 m / min to raise the maximum temperature of the material to 925 ° C., and subsequently passed through a cooling zone and a water-cooled pool to be quenched, and then subjected to solution treatment. Was done. The holding time of the material at 900 ° C. or higher was 1 minute, and the cooling time from 900 ° C. to 500 ° C. was 48 seconds. Further, after polishing the front and rear surfaces, the thickness was reduced to 1.25 mm by cold rolling. Next, annealing is performed in an electric furnace at a temperature of 600 ° C. for 2 hours in a nitrogen gas atmosphere, at a cooling rate of 5 ° C./min for 2 hours, and at a cooling rate of 500 ° C. for 2 hours. Further, annealing was performed at a temperature of 450 ° C. for 2 hours, and the temperature was lowered to room temperature at a cooling rate of 5 ° C. per minute. Next, the thickness was reduced to 0.25 mm by cold rolling. As shown in Table 1, the characteristics at this time were a conductivity of 72% IACS, a Vickers hardness of 158 Hv, and a tensile strength of 563 N / mm ² .
Further, after holding at a temperature of 450 ° C. for 5 minutes, Vickers hardness was measured to be 143 Hv.

Example 2 Various metal contents of a copper-based alloy,
And the process of ingot or hot treatment is performed in the same manner as in Example 1,
The plate thickness was 2.5 mm. Next, the material was held at 925 ° C. for 10 minutes in a batch-type electric furnace, and then rapidly cooled in a water-cooled pool to perform a solution treatment. The cooling time of the material from 900 ° C. to 500 ° C. was 48 seconds as in Example 1.
Thereafter, the same refining and cold rolling as in Example 1 were performed to obtain a sheet thickness of 0.25 mm. As shown in Table 1, the characteristics at this time were as follows: conductivity 72% IACS, Vickers hardness 1
It was 59 Hv and a tensile strength of 566 N / mm ² . 4 more
After holding at a temperature of 50 ° C. for 5 minutes, the Vickers hardness was measured to be 146 Hv.

Example 3 The contents of various metals in a copper-based alloy and the steps of ingot making, hot treatment or solution treatment were performed in the same manner as in Example 1, and the sheet thickness was 1.25 mm by cold rolling. And Thereafter, in an electric furnace, annealed in a nitrogen gas atmosphere at a temperature of 600 ° C. for 2 hours, further cooled at a rate of 5 ° C./minute for 2 hours at a temperature of 450 ° C., and cooled at a rate of 5 ° C./min. Lowered to Next, the thickness is 0.25 mm by cold rolling.
And As shown in Table 1, the characteristics at this time were as follows.
5% IACS, Vickers hardness 158Hv, tensile strength 5
53 N / mm ² . After holding at a temperature of 450 ° C. for 5 minutes, the Vickers hardness was measured.
Met.

Comparative Example 1 Various metal contents of a copper-based alloy
And the process of ingot or hot treatment is performed in the same manner as in Example 1,
The plate thickness was 2.5 mm. Next, in a continuous annealing furnace, the material is passed through a heating zone at an ambient temperature of 930 ° C. at a speed of 2 m / min to make the maximum temperature of the material 925 ° C., and then rapidly cooled by passing through a cooling zone and a water-cooled pool. Was done. Hold time of material at 900 ℃ or more is 1 minute, 900 ℃
The cooling time from to 500 ° C. was 480 seconds. As shown in Table 1, the characteristics at this time were as follows.
S, Vickers hardness 155 Hv, tensile strength 526 N / m
m ² . Further, after holding at a temperature of 450 ° C. for 5 minutes, the Vickers hardness was measured to be 97 Hv.

Comparative Example 2 Various metal contents of copper-based alloy
And the process of ingot or hot treatment is performed in the same manner as in Example 1,
The plate thickness was 2.5 mm. Next, in a continuous annealing furnace, the material is passed through a heating zone at an ambient temperature of 930 ° C. at a speed of 5 m / min to reach a maximum temperature of 850 ° C., and then rapidly cooled by passing through a cooling zone and a water-cooled pool. went. The retention time of the material at temperatures above 800 ° C. was 1 minute. Thereafter, the same refining and cold rolling as in Example 1 were performed to obtain a sheet thickness of 0.25 mm. As shown in Table 1, the characteristics at this time were as follows: conductivity 71% IACS, Vickers hardness 156
Hv and tensile strength were 540 N / mm ² . Further 450
After maintaining at a temperature of 5 ° C. for 5 minutes, the Vickers hardness was measured and found to be 106 Hv.

COMPARATIVE EXAMPLE 3 The various metal contents of the copper-based alloy and the steps of ingot making, hot treatment or solution treatment were performed in the same manner as in Example 1, and the sheet thickness was 1.25 mm by cold rolling. And Next, in an electric furnace, annealed in a nitrogen gas atmosphere at a temperature of 700 ° C. for 2 hours, and at a cooling rate of 5 ° C./min.
Annealing was performed at a temperature of 450C for 2 hours during the cooling at a cooling rate of 5C per minute, and the temperature was lowered to room temperature at a cooling rate of 5C per minute. Next, the thickness is 0.25 mm by cold rolling.
And At this time, as shown in Table 1, the electrical conductivity was 65% IACS, the Vickers hardness was 151 Hv, and the tensile strength was 514 N / mm ² . After further holding at a temperature of 450 ° C. for 5 minutes, the Vickers hardness was measured to be 84 Hv
Met.

[Comparative Example 4] The various metal contents of the copper-based alloy and the steps of ingot making, hot treatment or solution treatment were performed in the same manner as in Example 1, and the sheet thickness was 1.25 mm by cold rolling. And Next, annealing is performed in an electric furnace at a temperature of 520 ° C. for 2 hours in a nitrogen gas atmosphere.
Annealing was performed at a temperature of 450C for 2 hours during the cooling at a cooling rate of 5C per minute, and the temperature was lowered to room temperature at a cooling rate of 5C per minute. Next, the thickness is 0.25 mm by cold rolling.
And At this time, as shown in Table 1, the electrical conductivity was 68% IACS, the Vickers hardness was 154 Hv, and the tensile strength was 530 N / mm ² . After holding at a temperature of 450 ° C. for 5 minutes, the Vickers hardness was measured.
v.

[Comparative Example 5] The various metal contents of the copper-based alloy and the steps of ingot making, hot treatment or solution treatment were performed in the same manner as in Example 1, and the sheet thickness was 1.25 mm by cold rolling. And Thereafter, annealing was performed at a temperature of 600 ° C. for 2 hours in a nitrogen gas atmosphere in an electric furnace, and the temperature was lowered to room temperature at a cooling rate of 5 ° C./min.
Next, the thickness was reduced to 0.25 mm by cold rolling. As shown in Table 1, the characteristics at this time were as follows: a conductivity of 58% IACS,
Vickers hardness 160Hv, tensile strength 565N / mm ²
Met. Further, after holding at a temperature of 450 ° C. for 5 minutes, the Vickers hardness was measured to be 147 Hv.

Comparative Example 6 The various metal contents of the copper-based alloy and the steps of ingot making, hot treatment or solution treatment were performed in the same manner as in Example 1, and the sheet thickness was 1.25 mm by cold rolling. And Further, the subsequent steps of refining and cold rolling were performed in the same manner as in Example 1, and the plate thickness was set to 0.125 mm. As shown in Table 1, the characteristics at this time were as follows.
S, Vickers hardness 158Hv, tensile strength 558N / m
m ² . Further, after holding at a temperature of 450 ° C. for 5 minutes, the Vickers hardness was measured to be 114 Hv.

[0041]

[Table 1]

As shown in Comparative Example 1 of Table 1, the cooling rate in the solution treatment was 100 ° C./min. If it is slower, the hardness after heating the final material to 450 ° C. will be less than 140 Hv. Further, as shown in Comparative Example 2, the same applies even when the solution temperature is lower than 900 ° C. The same applies to the case where the aging temperature in the first sintering exceeds 650 ° C. as shown in Comparative Example 3 and the case where it is lower than 550 ° C. as shown in Comparative Example 4. In particular, when the aging temperature during sintering exceeds 650 ° C., the decrease in strength is also large. When the second refining step is omitted as shown in Comparative Example 5, the conductivity is less than 60% IACS. Also, as shown in Comparative Example 6, when the finish rolling degree was set to 90%, the hardness of the final material after heating at 450 ° C. was 120 Hv.
It becomes below.

On the other hand, as shown in Examples 1 to 3, under the conditions of the solution treatment and the aging condition of the refining process in the present invention, the conductivity was 70% IACS or more, and the tensile strength was 550 N.
/ Mm ² or more, Vickers hardness 155Hv or more,
Furthermore, even after heating at 450 ° C. for 5 minutes, 90% or more of the strength is maintained, and suitable performance can be obtained with an electric / electronic component material represented by a lead frame.

[0044]

As described above, according to the copper-based alloy of the present invention and the method for producing the same, it is possible to provide a copper-based alloy having high electrical conductivity, high strength and high heat resistance. In particular, according to the present invention, it is possible to provide an alloy having heat resistance in which the strength is maintained at 90% or more of that before heating even after heating at 450 ° C. for 5 minutes. In addition, since it is possible to produce the composition only by improving the production method without changing the conventional composition, there is an advantage that high strength, high conductivity and high heat resistance can be imparted without impairing the original performance.

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Claims (2)

[Claims] 1. Iron (Fe) 2.0-2.5% by weight, phosphorus (P) 0.01-0.2% by weight, zinc (Zn) 0.01
Manufactured from an ingot of a copper-based alloy containing
Having a conductivity of 0% IACS or more, a tensile strength of 520 N / mm ² or more, and a Vickers hardness of 155 Hv or more;
A high-strength, high-conductivity, high-heat-resistant copper base, which maintains at least 90% of the electrical conductivity, the tensile strength, and the Vickers hardness after being heated at 450 ° C. for 5 minutes. alloy. 2. The method according to claim 1, wherein copper (Cu) is a main component and iron (F) is used.
e) 2.0-2.5% by weight, phosphorus (P) 0.01-0.
An ingot of a copper-based alloy containing 2% by weight and zinc (Zn) of 0.01 to 1% by weight is hot-rolled at 800 to 1050 ° C, then cold-rolled, and heated at a temperature of 900 ° C or more at 30 ° C. Immediately after holding for more than 2 seconds, it is rapidly cooled to 500 ° C at a cooling rate of 100 ° C or more per minute, further cooled to room temperature, cold rolled, and annealed at a temperature of 550 to 650 ° C for 30 minutes to 6 hours. And further annealing at a temperature of 400 to 525 ° C. for 1 to 10 hours, and performing cold rolling at a finish rolling degree of 70 to 85%. Production method.