JPH06108212A - Production of precipitation type copper alloy - Google Patents

Abstract

PURPOSE:To obtain a precipitation type Cu alloy material having high workability, strength, and electric conductivity by improving the solution heat treatment, recrystallization treatment, and aging treatment for a precipitation hardening Cu alloy containing Cr, Sn, etc. CONSTITUTION:A cast ingot of a Cu alloy which has a composition consisting of, by weight, 0.1-0.35% Cr, 0.05-0.5% Sn, and the balance Cu or further containing 0.05-5.0% Zn or further containing 0.0005-1.0%, in total, of one or >=2 kinds among specific small amounts of Si, Mn, Mg, V, Ti, B, and P is subjected to hot working starting at 880-1050 deg.C and then cooled rapidly to undergo cold working. Subsequently, heat treatment, in which holding is done at 360-650 deg.C for 45-1800sec or holding is done at 880-1020 deg.C for 5-60sec, and a high density pulse current applying treatment are simultaneously performed. Then, cold working is done, and, at the time of performing aging heat treatment, an electric field of (1 to 10)KV/cm is impressed simultaneously. By this method, an electronic and electrical equipment material combining superior workability with a high strength and electric conductivity can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a precipitation-type copper alloy having excellent workability, high strength and conductivity, and high reliability. It is suitable as a material for electronic and electrical equipment such as a spring material and a lead frame material.

[0002]

2. Description of the Related Art Light, thin, short, and small devices in the electronic and electrical industries in recent years have promoted downsizing, weight reduction, and higher integration of equipment used therein, and accordingly, downsizing of their components.・ Lighter weight and higher performance are required. In response to this demand, structural materials that form the basis of component parts, connectors, lead frame materials, etc. are becoming thinner and highly integrated due to their smaller size and lighter weight, and the problem of heat generation cannot be ignored. Therefore, there has been a need for materials having good thermal conductivity.

Under these circumstances, as a high-strength conductive material, "Cu-Ni-Si" (JP-A-58-124254) and "Cu-Cr-Sn" (JP-A-63-69933). Gazette)
Precipitation hardenable copper alloys such as the above have been widely used. These alloys, in common, exhibit their original properties by a solution treatment at high temperature, followed by a processing treatment and an aging treatment.

However, in the solution treatment for holding the precipitated component as a solid solution component in the matrix, the recrystallization phenomenon in the structure proceeds excessively while the material is held at a high temperature for solution treatment, and recrystallized grains It shows the influence of deterioration of the ductility of the material and the surface properties when stress is applied. For this reason, it is necessary to control the recrystallization phenomenon during solution treatment, and continuous solution treatment technology (Japanese Patent Laid-Open No. 3-56650) has been performed in which the material is continuously solution treated. , It showed some effect, but it was not enough.

[0005]

Based on the above technique, the present invention aims to obtain higher various characteristics in response to the performance requirements of electronic and electrical equipment parts which will increase further in the future. , We have developed the conventional solution heat treatment technology, recrystallization treatment technology and aging treatment technology for precipitation hardening type copper alloys containing Sn element as the main component, and have developed a manufacturing method for producing higher performance precipitation type copper alloys. It was developed.

That is, one of the production methods of the present invention is as follows: Cr: 0.1-
0.35 wt%, Sn: 0.05-0.5 wt%, or further Z
n: 0.05 to 5.0 wt%, copper alloy ingot composed of the balance Cu and unavoidable impurities is subjected to hot working starting from a temperature range of 880 to 1050 ° C, and is subjected to rapid cooling treatment and cold working. 1 to 10 kV / cm at the same time when aging heat treatment is performed after adding
Is applied.

Another manufacturing method of the present invention is Cr: 0.1-
0.35 wt%, Sn: 0.05-0.5 wt%, or further Z
n: 0.05 to 5 wt%, a copper alloy ingot composed of the balance Cu and unavoidable impurities is subjected to hot working starting from a temperature range of 880 to 1050 ° C, and rapid cooling treatment is performed to perform cold working. After the addition, the heat treatment of holding at 350 to 650 ℃ for 45 to 1800 seconds and the high-density pulse current addition treatment are performed at the same time, and after cold working, the aging heat treatment is performed simultaneously for 1 to 10 seconds.
It is characterized by applying an electric field of kV / cm.

Still another method of the present invention is Cr:
0.1 to 0.35 wt%, Sn: 0.05 to 0.5 wt%, or Zn: 0.05 to 5 wt%, and a balance of Cu and inevitable impurities in a copper alloy ingot, from a temperature range of 880 to 1050 ° C. After performing hot working to start, rapid cooling treatment and cold working, heat treatment of holding at 880 to 1020 ° C for 5 to 60 seconds and high-density pulse current addition treatment are simultaneously performed, and then cold working At the same time when performing the aging heat treatment after performing
It is characterized by applying an electric field of ~ 10 kV / cm.

The copper alloy of each of the above inventions further comprises Si:
0.005-0.1 wt%, Mn: 0.01-0.5 wt%, Mg: 0.0
05-0.5 wt%, V: 0.005-0.1 wt%, Ti: 0.01-0.
25wt%, B: 0.005-0.05wt%, P: 0.0005-0.01wt%
0.0005 to 1.0 wt in total of 1 or 2 or more from the group consisting of
%, The above three production methods of the present invention can be applied.

[0010]

The function and the reason for limitation of the method for producing a precipitation-type copper alloy according to the present invention will be described below.

First, the Cr element exists as a single precipitate in the present copper alloy, and when it is dispersed uniformly and finely, it improves the material strength and the conductivity thereof. Is what you do. Therefore, the reason for limiting the content to 0.1 to 0.35 wt% is
If it is less than 0.1 wt%, its effect is poor, and if it is too much, Cu-C
It is limited in order to form a eutectic of r and impair the material strength, hot workability and plating adhesion.

One of the functions of the Sn element is that the Sn element itself acts as a solid solution component in the copper alloy to improve material strength and material ductility and bending workability. The second function is to show the effect of relaxing the dependency of the cooling rate on the precipitation phenomenon of Cr element during cooling from a conventionally known high temperature state. Therefore, the content of 0.05 to 0.5 wt% is because the above effect is weak when the content is less than 0.05 wt% and the high conductivity which is the characteristic of the alloy system is remarkable when the content exceeds 0.5 wt%. It is limited because it is lost.

Next, the addition of Zn element is carried out by adding Sn alloy or Sn--
It shows the effect of suppressing the time deterioration of the bonding strength with respect to the ambient temperature at the time of bonding with a dissimilar metal such as Pb alloy, and also has the effect of improving the migration resistance. Therefore, the content of 0.05 to 5 wt% is
If it is less than 0.05 wt%, its effect is small, and if it exceeds 5 wt%, the above effect is maintained, but the conductivity is impaired.
Insufficient heat dissipation of the heat generated by the connection of the connector and the operation of the IC chip in the lead frame, and the Zn element is sublimated at a temperature lower than the melting point of Cu, Cr, Sn elements, etc. Therefore, it is limited because the element yield and the workability are deteriorated.

Si, Mg, Mn, V, Ti, B, P
For the group consisting of the elements of, all of these contribute to the improvement of the workability in the manufacturing process within the scope of the claims, and particularly in the case of Mg and Mn elements, like the Zn element,
At the time of joining with dissimilar metals such as Sn alloys and Sn-Pb alloys, it shows a function of suppressing time deterioration of the joining strength against environmental temperature, and also contributes to the improvement of strength and springiness as a solid solution component. To do. And Si, V, T
The elements i, B, and P suppress the coarsening of recrystallized grains due to excessive conditions during the simultaneous heat treatment and high-density pulse current addition treatment, which are the features of the present invention, and thus the surface during bending is reduced. By keeping the state smooth and preventing defects such as surface cracks, the bending workability is improved. However, if these additive elements are contained in amounts exceeding the respective upper limits, the castability deteriorates, not only it becomes difficult to obtain a sound ingot, but also the hot workability is adversely affected. Furthermore, the adhesion and conductivity of the plating are impaired.

Next, regarding the condition of the heat treatment step, which is the essence of the manufacturing method according to the present invention, its action and the reason for limitation will be described below.

In the manufacturing method of the present invention, first, the precipitation is carried out by hot working starting from a temperature sufficient to form a solid solution of precipitates in the alloy, that is, from 880 to 1050 ° C. and rapidly cooling with water cooling etc. at the end of the hot working. A supersaturated solid solution containing few substances is formed, and appropriate cold working is performed later.

In the subsequent aging heat treatment, the copper alloy is sandwiched in a non-contact state so that the electrode plates face each other, and a voltage is applied to the electrode plates to form an electric field between the electrode plates, that is, the copper alloy is formed. Aging heat treatment is carried out while being held in an electric field.
If the electric field is applied at the same time as the aging heat treatment in this way, the reason is not yet clear, but the material recovery / recrystallization process does not affect the precipitation process so much. Has a function of delaying for a long time. As a result, it is possible to further improve the conductivity while increasing the ductility of the material while maintaining the resistance of the material strength, which is the reciprocal characteristic, to temperature. The strength of the applied electric field was set at 1.0 to 10 kV / cm. This is because the effect is not seen when the electric field strength is less than 1 kV / cm,
If it exceeds 10 kV / cm, the effect will be stagnant and energy will be consumed unnecessarily, resulting in high material cost.

The condition of the aging heat treatment is 250
The temperature should be kept at ~ 550 ℃ for about 10 ~ 360 minutes, which gives good characteristics.

Further, in the present invention, a heat treatment combined with a high-density pulse current addition treatment may be applied before the aging heat treatment. That is, by performing high-density pulse current addition treatment during heat treatment for holding in the temperature range of 350 to 650 ° C for 45 to 1800 seconds or in the temperature range of 880 to 1020 ° C for 5 to 60 seconds, the precipitation in the previous step occurs. It is possible to prevent coarsening of the deposited precipitates, maintain the solid solution state of the precipitation components that are currently in solid solution state, and further recrystallize the crystal structure of the alloy during the heat treatment. The subsequent cold working and aging heat treatment produce a copper alloy having excellent properties.

The heat treatment conditions are as follows: holding the material in the temperature range of 350 to 650 ° C. for 45 to 1800 seconds;
Alternatively, holding the material for 5 to 60 seconds in the temperature range of 80 to 1020 ° C. has a great effect on the suppression of coarsening of existing precipitates and the suppression of precipitation of non-precipitated components under the additional treatment of high-density pulse current, at the same time, This is a condition that also contributes to rapid recrystallization of the alloy structure. However, a combination of temperature and time exceeding this causes coarsening of existing precipitates and precipitation of unprecipitated components, which causes various properties such as strength and bending workability to deteriorate. Also, in the case of a combination of low temperature and short time, even if high-density current pulse addition treatment is performed, recrystallization of crystal grains does not proceed and the non-uniformity of the structure increases, and the precipitation of solid solution in the matrix occurs. This is because the precipitation of the components occurs in reverse.

The high-density current pulse addition treatment has a function of promoting the recrystallization phenomenon of the alloy structure, and when used in combination with the above heat treatment, coarsening of precipitates deposited in the previous step It is possible to more efficiently recrystallize the crystal structure of the alloy structure in a short time while controlling the suppression and maintaining the solid solution state of the precipitation component which is presently in the solid solution state. The conditions are current density 10 to 10 ⁴ A
/ Mm ² , pulse width 20 to 250 μs, pulse period 1 to 10 ³ Hz
Within the range of, effective effects are shown.

Further, in order to carry out the above manufacturing method more efficiently and enhance the alloy characteristics, in the hot working of the alloy according to the manufacturing method of the present invention, the alloy ingot is heated to a temperature of 880 to 1050 ° C. It is desirable to carry out hot working and cool quickly after completion. In particular, rapid cooling by means such as water cooling up to a temperature range of about 400 ° C. improves the alloy properties in the subsequent steps.

Further, after the final cold working, a tension leveler for tempering annealing in the temperature range of 300 to 550 ° C. or straightening the material shape by adding tension and bending strain, and adjusting the temperature of the material in the temperature range of 400 to 850 ° C. By combining quality and tension leveler annealing for shape correction, it is possible to obtain more balanced and high characteristics.

[0024]

EXAMPLE After melting and casting a copper alloy having the composition shown in Table 1,
Heat treatment and hot and cold working were performed by any of the following methods α, β, or γ to prepare test materials.

[0025]

[Table 1]

Manufacturing method α The copper alloy ingot is hot-rolled at 1020 ° C., and after completion of the hot rolling, the material is cooled by directly putting it in water. This was ground into a plate with a thickness of 5 mm, and this plate was cold-worked to a plate with a thickness of 0.5 mm, and then subjected to an electric field aging heat treatment under one of the conditions shown in Table 2 as shown in Table 5. The surface is pickled and cold-worked at a working rate of 40% to obtain a thickness of 0.3
After finishing to a plate of mm, the sample is prepared by tempering annealing at 375 ° C for 60 minutes.

Manufacturing method β The copper alloy ingot is hot-rolled at 1020 ° C., and after completion of the hot rolling, the material is cooled by directly putting it in water. This was ground into a plate with a thickness of 5 mm, and this plate was cold-worked to form a plate with a thickness of 0.5 mm, and the conditions shown in Tables 3 and 4 were combined as shown in Table 5 to cause precipitation. Suppressing recrystallization heat treatment,
After quenching and returning the material to room temperature, it is subjected to surface pickling grinding and cold working at a working rate of 40% to finish a plate with a thickness of 0.3 mm. After that, as shown in Table 5, electric field aging heat treatment was applied under one of the conditions shown in Table 2, and then the plate thickness was 0.2 mm.
Cold-rolling up to this point and temper annealing at 350 ° C for 60 minutes to prepare the test material.

Manufacturing Method γ The copper alloy ingot is hot-rolled at 950 ° C., and immediately after that, the material is cooled by directly putting it in water. This was ground into a plate with a thickness of 5 mm, and this plate was cold-worked to form a plate with a thickness of 0.5 mm, and the conditions shown in Tables 3 and 4 were combined as shown in Table 5 to cause precipitation. Suppressing recrystallization heat treatment,
After quenching and returning the material to room temperature, it is subjected to surface pickling grinding and cold working at a working rate of 40% to finish a plate with a thickness of 0.3 mm. Thereafter, as shown in Table 5, an electric field aging heat treatment is applied under any of the conditions shown in Table 2 to prepare a test material.

[0029]

[Table 2]

[0030]

[Table 3]

[0031]

[Table 4]

[0032]

[Table 5]

Tensile strength, elongation, conductivity, bending workability, solder releasability and plating adhesion of each of these test materials were measured by the following methods, and the results are shown in Table 6.

Regarding the tensile strength and elongation, JIS-Z
2241. Conductivity is measured according to JIS-H050.
The conductivity was determined based on No. 5. Bending workability is JIS-Z
The test was conducted by the V-block method of 2248, and the minimum bending radius (R) at which the surface of the test piece was cracked was divided by the thickness (t) of the test piece and shown by a value (R / t). Heat-resistant solder releasability is measured by stripping a strip-shaped test piece with a width of 5 mm from the test material and immersing 60/40 eutectic solder in it with rosin flux, and then 500, 750 at 170 ℃. Then, after conducting a heating test for 1000 hours, contact bending of 180 degrees was performed, and the presence or absence of peeling of the solder was observed. If peeling was already recognized by 500 hours, it was marked as "x", if it was peeled by 750 hours was marked as "△", if it was peeled after 1000 hours was marked as "○", and if it was not peeled even after 1000 hours was marked as "○". ◎ ”. For the plating adhesion, after plating Ag to a thickness of 5.0 μm in a cyanide bath and heating at 450 ° C. for 10 minutes, a tape peeling test was performed to observe the presence or absence of peeling.

[0035]

[Table 6]

As is clear from Table 6, the properties of the copper alloys No. 1 to No. 9 produced by the production method of the present invention are equal to or more than the strength and elongation of No. 16 produced by the conventional production method. Further, it can be seen that the electroconductivity and bending workability are more excellent, and the solder releasability and plating adhesion are also good.

On the other hand, the samples according to the comparative examples which are out of the conditions of the present invention are greatly inferior in characteristics. That is, the content of any one of the alloy components was too high, the No. 10 according to the comparative example,
The 11,15 copper alloys have sufficient strength, but are inferior in conductivity, bending workability, plating adhesion and the like. In addition, the copper alloy of No. 14 according to the comparative example, which has a low heat treatment temperature under the heat treatment conditions, has a nonuniform recrystallized structure even after a long time treatment, resulting in deterioration of bending workability and plating adhesion. On the other hand, the copper alloy No. 12 according to the comparative example, which has a too high heat treatment temperature, is inferior in strength and bending workability due to coarsening of crystal grains and re-dissolution of precipitates. Further, it can be seen that the properties of the No. 13 copper alloy according to the comparative example having a weak electric field strength are deteriorated.

[0038]

According to the manufacturing method of the present invention, a material for electronic and electrical equipment such as a connector, a terminal material, a spring material and a lead frame material, which has excellent workability, high strength and conductivity, and has high reliability. The obtained product has a remarkable industrial effect.

Claims (6)

[Claims] 1. Cr: 0.1-0.35 wt%, Sn: 0.05-0.
A copper alloy ingot containing 5 wt% or further Zn: 0.05 to 5.0 wt% and the balance Cu and inevitable impurities was subjected to hot working starting from a temperature range of 880 to 1050 ° C. A method for producing a precipitation-type copper alloy, which comprises applying an electric field of 1 to 10 kV / cm at the same time when performing an aging heat treatment after performing a cooling treatment and cold working. 2. The copper alloy according to claim 1, further comprising Si:
0.005-0.1 wt%, Mn: 0.01-0.5 wt%, Mg: 0.0
05-0.5 wt%, V: 0.005-0.1 wt%, Ti: 0.01-0.
25wt%, B: 0.005-0.05wt%, P: 0.0005-0.01wt%
0.0005 to 1.0 wt in total of 1 or 2 or more from the group consisting of
%, The method for producing a precipitation-type copper alloy according to claim 1. 3. Cr: 0.1-0.35 wt%, Sn: 0.05-0.
5 wt% or further Zn: 0.05-5 wt%,
To the copper alloy ingot which consists of the balance Cu and unavoidable impurities, 8
Perform hot working starting from the temperature range of 80 to 1050 ℃, perform rapid cooling treatment and add cold working, then at 350 to 650 ℃
It is characterized in that a heat treatment of holding for 45 to 1800 seconds and a high-density pulse current addition treatment are performed at the same time, and after cold working, an electric field of 1 to 10 kV / cm is simultaneously applied when performing aging heat treatment. Manufacturing method of precipitation-type copper alloy. 4. The copper alloy according to claim 3, further comprising:
0.005-0.1 wt%, Mn: 0.01-0.5 wt%, Mg: 0.0
05-0.5 wt%, V: 0.005-0.1 wt%, Ti: 0.01-0.
25wt%, B: 0.005-0.05wt%, P: 0.0005-0.01wt%
0.0005 to 1.0 wt in total of 1 or 2 or more from the group consisting of
%, The method for producing a precipitation-type copper alloy according to claim 3. 5. Cr: 0.1-0.35 wt%, Sn: 0.05-0.
5 wt% or further Zn: 0.05-5 wt%,
To the copper alloy ingot which consists of the balance Cu and unavoidable impurities, 8
After performing hot working starting from the temperature range of 80 to 1050 ℃, performing rapid cooling treatment and cold working, heat treatment to hold at 880 to 1050 ℃ for 5 to 60 seconds and high-density pulse current addition treatment. The method for producing a precipitation-type copper alloy is characterized in that an electric field of 1 to 10 kV / cm is applied at the same time when aging heat treatment is performed after simultaneously performing the cold working and the cold working. 6. The copper alloy according to claim 5, further comprising Si:
0.005-0.1 wt%, Mn: 0.01-0.5 wt%, Mg: 0.0
05-0.5 wt%, V: 0.005-0.1 wt%, Ti: 0.01-0.
25wt%, B: 0.005-0.05wt%, P: 0.0005-0.01wt%
0.0005 to 1.0 wt in total of 1 or 2 or more from the group consisting of
%, The method for producing a precipitation-type copper alloy according to claim 5.