KR101786411B1 - Copper alloy plate, and electronic part for heat dissipation use which is equipped with same - Google Patents

Abstract

The copper alloy sheet of the present invention contains 0.01 to 0.3% by mass of Sn and the balance of copper and inevitable impurities. The copper alloy sheet has an electrical conductivity of 75% IACS or more and a 0.2% proof stress of 300 MPa or more, (R ₀ + r ₉₀ + 2 x r ₄₅ ) / 4, where r ₀ , r ₉₀ and r ₄₅ are the respective rank pod values in the parallel direction, the right angle direction and the 45 ° direction, The plate thickness anisotropy (r) becomes 1.0 or more.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a copper alloy plate and a heat dissipation electronic component having the copper alloy plate,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper alloy plate having excellent heat dissipation properties, conductivity and drawing processability, and more particularly to a copper alloy plate for use in electronic parts such as a terminal, a connector, a relay, a switch, a socket, a bus bar and a lead frame, And more particularly to a copper alloy plate suitable for use as a heat-radiating component and a high-current component.

Components for obtaining electrical connection such as terminals, connectors, switches, sockets, relays, bus bars, and lead frames are inserted into electric and electronic devices such as smart phones, tablet PCs, and personal computers.

In recent years, with the miniaturization of smart phones, tablet PCs, and personal computers, there is a tendency that the heat storage when energizing liquid crystal parts or IC chips in electric and electronic devices increases. In a state where the heat storage is large, thermal damage to the IC chip or the base is large, so that heat dissipation of the heat dissipation parts becomes a problem.

Background Art Conventionally, austenitic stainless steel and pure aluminum have been mainly used for heat dissipation parts in electric and electronic devices such as smart phones, tablet PCs, and personal computers. For example, a heat dissipation component (liquid crystal frame) attached to a liquid crystal of a smart phone or a tablet PC is required to have strength as a structure and bending property or drawability required for fixation to a liquid crystal in addition to high heat dissipation.

The austenitic stainless steel has good bendability and drawability, but is low in thermal conductivity, and an expensive heat conductive sheet or the like is used in combination to supplement it. Therefore, the unit price of the heat-dissipating component becomes high. On the other hand, in pure aluminum and aluminum alloy, bending property and drawing workability were good, but the thermal conductivity and strength as a structural body were not sufficient.

On the other hand, among the copper alloys, it is known that the Cu-Sn based alloy is in a proportional relationship with the thermal conductivity, and it can be produced at a low cost with a high electrical conductivity, A copper alloy containing 0.12% by mass of Sn is practically provided as a CDA (Copper Development Association) alloy number C14415. In addition, Cu-Sn alloy has been used as a copper alloy foil for a flexible printed base of a cellular phone or a negative electrode current collector of a secondary battery such as a lithium ion secondary battery.

Japanese Patent Application Laid-Open No. 2005-048262

However, although the conventional Cu-Sn alloy has high strength and high heat conductivity, it does not satisfy the required bending property or drawing workability, and in some cases, it is not satisfactory.

Therefore, it is industrially very significant to improve the bendability and the drawing processability while maintaining the strength and the electric conductivity with the Cu-Sn alloy.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a copper alloy plate having high strength, high electrical conductivity, excellent drawing processability, and bending workability, and a heat dissipation electronic component having the same.

The present inventors have found that drawing-formability and bending workability are improved by controlling the values of the plate thickness anisotropy obtained from the rank pod values measured at three orientations in a plane in a Cu-Sn-based alloy.

Based on the above findings, the following inventions were completed.

The copper alloy sheet of the present invention contains 0.01 to 0.3% by mass of Sn and the balance of copper and inevitable impurities. The copper alloy sheet has an electrical conductivity of 75% IACS or more and a 0.2% proof stress of 300 MPa or more, (R ₀ + r ₉₀ + 2 x r ₄₅ ) / 4, where r ₀ , r ₉₀ and r ₄₅ are the respective rank pod values in the parallel direction, the right angle direction and the 45 ° direction, And the plate thickness anisotropy (r) is 1.0 or more.

In the copper alloy sheet of the present invention, the minimum bending radius / plate thickness (MBR / t) in the rolling parallel direction (GW direction) and in the direction perpendicular to the rolling direction (BW direction) in the W bending test is given as MBR / .

In addition, in the copper alloy sheet of the present invention, at least one of Ag, P, Co, Ni, Cr, Mn, Zn, Mg and Si may be added in an amount of 0.15 mass% or less in total in addition to Sn. All of these elements contribute to the improvement of the strength, but if the addition amount is too large, the conductivity is lowered, the raw material cost is increased, or the composition is deteriorated. Therefore, the upper limit is preferably 0.15 mass%.

Further, the heat dissipation electronic component of the present invention comprises any of the above-described copper alloy plates.

According to the present invention, it is possible to provide a copper alloy plate having high strength, high conductivity and excellent drawing processability. This copper alloy plate can be suitably used as a material for electronic parts such as terminals, connectors, switches, sockets, relays, bus bars, and lead frames. The copper alloy plate can be used for applications such as smart phones and personal computers, The present invention relates to a copper alloy sheet.

Hereinafter, embodiments of the present invention will be described in detail.

The copper alloy sheet according to one embodiment of the present invention has a composition of 0.01 to 0.3 mass% of Sn and the balance of copper and inevitable impurities. The copper alloy plate has a conductivity of 75% IACS or more and 0.2% The proof stress is set to 300 MPa or more, and the plate thickness anisotropy determined from the rank pod value is adjusted to 1.0 or more. The copper alloy plate of the present invention having such characteristics is preferable for use in heat dissipation electronic parts.

(Alloy component concentration)

The Sn concentration is set to 0.01 to 0.3 mass%. If Sn is more than 0.3% by mass, it is difficult to obtain a conductivity higher than 75% IACS. When Sn is less than 0.01% by mass, 0.2% proof stress of 300 MPa or more can not be obtained. From the same viewpoint, the Sn concentration is preferably 0.03 to 0.25 mass%, particularly preferably 0.08 to 0.25 mass%.

In addition to Sn, at least one element selected from the group consisting of Ag, P, Co, Ni, Cr, Mn, Zn, Mg and Si may be added to the Cu-Sn alloy of the present invention. Is preferably 0.15 mass% or less in total. When the total amount exceeds 0.15 mass%, the conductivity is lowered, the cost of the raw material is increased, or the composition is deteriorated.

(Conductivity)

In the present invention, the conductivity measured according to JIS H 0505 is 75% IACS or more. When the conductivity is 75% IACS or more, the thermal conductivity is good and good heat radiation can be ensured. The conductivity is preferably 80% IACS or higher.

(0.2% proof)

In the present invention, the 0.2% proof stress of the copper alloy sheet is set to 300 MPa or more. In this case, the copper alloy sheet may have the strength required for the material of the structural material. The 0.2% proof stress is preferably 350 MPa or more, and more preferably 400 MPa or more.

(Drawing processability)

R ₀ , r ₉₀ , and r ₄₅ in each direction were obtained from the change in dimension in the length and width direction of the test piece by applying a 2.5% elongation strain to each of the parallel, perpendicular, and 45 ° directions of the test piece. = (r ₀ + r ₉₀ + 2 x r ₄₅ ) / 4. It is known that the larger the value of the plate thickness anisotropy (r) is, the better the drawing processability is. In addition, the plate thickness anisotropy (r) of a general copper alloy article (expanded copper article) is about 0.5 to 0.9. In the present invention, by adjusting this value to 1.0 or more, excellent drawing workability can be obtained.

The rank pod value referred to herein is defined in JIS Z 2254, and the rank pod values r ₀ , r ₉₀ , and r _{45 described} above shall be measured in accordance with JIS Z 2254. However, in order to maintain the required strength as a structural member, the present invention has a low elongation and a load deformation of 2.5%.

In order to obtain better drawing processability, it is preferable that the plate thickness anisotropy (r) is 1.5 or more.

(thickness)

The thickness of the product, that is, the plate thickness t, is preferably 0.05 to 2.0 mm. If the thickness is too small, sufficient heat radiation property can not be obtained, which is unsuitable as a material for heat dissipation electronic parts. On the other hand, if the thickness is excessively large, drawing processing and bending processing become difficult. From this viewpoint, the more preferable thickness is 0.08 to 1.5 mm. When the thickness falls within the above range, the heat radiation property is excellent and the bending workability is good.

(Bending workability)

(MBR / t) of the minimum bending radius (MBR) with respect to the plate thickness (t) is not more than 2.0, and the minimum bending radius (MBR) of the copper alloy sheet is measured in accordance with JIS H 3130 , Particularly preferably 1.5 or less, from the viewpoint of ensuring good bendability. More preferably, MBR / t is set to 0.5 or less.

(Manufacturing method)

Hereinafter, an example of a preferable method for producing a copper alloy sheet according to the present invention will be described.

Copper and the like are dissolved as pure copper raw material, and Sn and, if necessary, other alloying elements are added and cast into an ingot having a thickness of about 30 to 300 mm. This ingot is formed into a plate having a thickness of about 3 to 30 mm by, for example, hot rolling at 800 to 1000 DEG C, and then cold rolling and recrystallization annealing are repeated, and the final ingot is finished to a predetermined product thickness in the final cold rolling, Stress relieving annealing is performed. The elongation after the final cold rolling is as low as less than 2%, but is increased by subsequent stress relief annealing.

In the recrystallization annealing, part or all of the rolled structure is recrystallized.

In the recrystallization annealing before the final cold rolling, the average crystal grain size of the copper alloy plate is adjusted to 80 탆 or less. If the average crystal grain size is too large, the 0.2% proof can not be adjusted well to 300 MPa or more. In order to increase the 0.2% proof stress, it is preferable to adjust the average crystal grain size to 60 탆 or less by recrystallization annealing before the final cold rolling, and more preferably 50 탆 or less.

The conditions of the recrystallization annealing before the final cold rolling are determined based on the targeted grain size after annealing and the conductivity of the target product. Specifically, annealing may be carried out by using a batch furnace or a continuous annealing furnace at a furnace temperature of 350 to 800 占 폚. In the batch furnace, the heating time may be appropriately adjusted within a range of 30 minutes to 30 hours at an in-furnace temperature of 350 to 600 ° C. In the continuous annealing furnace, the heating time may be appropriately adjusted within the range of 5 seconds to 10 minutes at the furnace temperature of 450 to 800 ° C. Generally, when annealing is performed at a lower temperature for a longer time, a higher conductivity can be obtained with the same crystal grain size.

In the final cold rolling, the material is repeatedly passed between the pair of rolling rolls to finish with the target plate thickness. And controls the total processability of the final cold rolling.

The total workability R (%) is given by R = (t ₀ - t) / t ₀ × 100 (t ₀ : plate thickness before final cold rolling, t: plate thickness after final cold rolling).

The total processing degree (R) is 20 to 99%, preferably 40 to 98.5%, more preferably 60 to 98%. If R is too small, the 0.2% proof can not be adjusted well to 300 MPa or more, and if R is too large, the edge of the rolled material may be cracked.

The stress relieving annealing of the present invention is carried out using a continuous annealing furnace capable of holding a copper alloy sheet in a flat state in a furnace. In the case of the arrangement, since the material is heated in a coiled state, the material undergoes plastic deformation during heating, causing warpage of the material. Thus, the batch is unsuitable for the stress relieving annealing of the present invention.

In the stress relieving annealing after rolling, the tension applied to the material in the continuous annealing furnace is adjusted to 1 to 5 MPa, more preferably 2 to 4 MPa. If the tension is excessively large, the plate thickness anisotropy (r) lowers, and it becomes difficult to adjust it to 1.0 or more. On the other hand, if the tensile force is too small, there is a possibility that the material passing through the annealing furnace comes into contact with the furnace wall and scratches the surface or edge of the material.

In the continuous annealing furnace, the furnace temperature is set to 300 to 700 占 폚, preferably 350 to 650 占 폚, the heating time is appropriately adjusted in the range of 5 seconds to 10 minutes, and the 0.2% Is adjusted to a value of 10 to 50 MPa lower, preferably 15 to 45 MPa lower than the 0.2% proof stress (? ₀ ) before the stress relieving annealing. As a result, the low elongation is increased and the bendability is improved in the final cold rolling elevation.

The present invention is characterized in that, in addition to the stress relieving annealing described above, a feature that the plate thickness anisotropy (r) ≤ 1.2 is obtained from the rank pod value is imparted to the Cu- Sn alloy to improve the drawing workability and the bending workability. . The manufacturing conditions for this are summarized as follows.

a. In stress relieving annealing, (σ ₀ - σ) = 10 to 50 MPa is adjusted.

b. The furnace tension in the stress relieving annealing is adjusted to 5 MPa or less.

c. The total working degree of the finish rolling should be 99% or less.

The copper alloy sheet produced in the above-described manner can be used as an electronic component for heat dissipation in electric / electronic devices such as smart phones, tablet PCs, and personal computers, for example.

Example

Examples of the present invention will now be described with reference to comparative examples, which are provided for a better understanding of the present invention and its advantages, and are not intended to limit the invention.

The alloy element was added to molten copper and then cast into an ingot having a thickness of 200 mm. The ingot was heated at 950 占 폚 for 3 hours and hot rolled at 950 占 폚 to form a plate having a thickness of 20 mm. The oxide scale on the surface of the hot-rolled plate was grinded and removed by a grinder, and then annealing and cold rolling were repeated, and the final cold-rolled was finished to a predetermined product thickness. Finally, stress relieving annealing was performed using a continuous annealing furnace.

Annealing (final recrystallization annealing) before final cold rolling was carried out by using a batch furnace to change the crystal grain size and the conductivity after annealing by adjusting the furnace temperature in the range of 300 to 700 캜 at a heating time of 5 hours. In the measurement of the crystal grain size after annealing, the cross section perpendicular to the rolling direction was chemically corroded after the mirror polishing, and the average crystal grain size was determined according to the cutting method (JIS H 0501 (1999)).

In the final cold rolling, the total degree of processing and the degree of processing per pass were controlled. Further, the 0.2% proof stress of the material after the final cold rolling was obtained.

In the stress relieving annealing using the continuous annealing furnace, the furnace temperature was set to 500 ° C and the heating time was adjusted between 1 second and 15 minutes to change the 0.2% after annealing various times. Also, the tension added to the material in the furnace was varied in various ways.

The following measurements were made on the material during manufacture and the material after stress relief annealing.

(ingredient)

The alloy element concentration of the material after stress relieving annealing was analyzed by ICP-mass spectrometry.

(0.2% proof)

For the material after the final cold rolling and after the stress relieving annealing, the test piece No. 13B specified in JIS Z 2241 was taken so that the tensile direction became parallel to the rolling direction, and a tensile test was performed in parallel with the rolling direction in accordance with JIS Z 2241 , And a 0.2% proof stress was obtained.

(Conductivity)

From the material after the stress relieving annealing, a test piece was taken so that the longitudinal direction of the test piece became parallel to the rolling direction, and the conductivity at 20 캜 was measured by the four-terminal method according to JIS H 0505.

(Plate thickness anisotropy)

A test piece of JIS 13B specified in JIS Z 2241 was taken in parallel to the rolling direction of the test piece, at a right angle, and at an angle of 45 °. The test specimens were each subjected to a tensile strain of 2.5% using a tensile tester to calculate plate thickness anisotropy.

(MBR / t)

A test piece having a width of 10 mm and a length of 30 mm was prepared and subjected to a W bending test (JIS H 3130). The direction of drawing the test specimens was evaluated by the ratio MBR / t between the minimum bend radius (MBR) and the plate thickness (t), in which the cracks did not occur, in the rolling parallel direction (GW) and in the direction perpendicular to the rolling direction (BW).

Tables 1 and 2 show the evaluation results. As shown in Table 1, the notation of "? 10 " in the crystal grain size after the final recrystallization annealing indicates that when all of the rolled structure is recrystallized and the average crystal grain size is 10 占 퐉 or less, And both of the case of recrystallization.

As can be seen from the results shown in Table 1, Inventive Examples 1 to 32 all contain 0.01 to 0.3 mass% of Sn, and the grain size of the final recrystallization annealing is 80 占 퐉 or less, Is 0.2 to 1.0 MPa, the conductivity is 75% or more, and the plate thickness anisotropy (r) is 1.0 to 1.0 MPa, since the tensile stress at annealing is 20 to 99% Thus, a material excellent in heat radiation property, strength and workability was obtained. In Inventive Examples 1 to 32, since the difference between the 0.2% proof stress after final rolling and the 0.2% proof stress after the stress relieving annealing was 10 to 50 MPa, the bending workability was good at both GW and BW of 1.5 or less.

On the other hand, as shown in Table 2, in Comparative Example 1, the Sn concentration was less than 0.01 mass% and the 0.2% proof stress was less than 300 MPa. In Comparative Example 2, the Sn concentration exceeded 0.3% by mass, the conductivity became less than 75%, and the heat dissipation performance was poor.

In Comparative Example 3, the additive element concentration other than Sn exceeded 0.15 mass%, the conductivity became less than 75%, and the heat dissipation performance was poor.

In Comparative Example 4, since the crystal grain size in the recrystallization annealing exceeds 80 탆, the 0.2% proof stress was less than 300 MPa.

In Comparative Example 5, the total working degree in the final rolling was less than 20%, so the 0.2% proof stress was less than 300 MPa.

In Comparative Example 6, since the product thickness exceeded 2.0 mm, the plate thickness anisotropy became less than 1.0 and the drawing processability was poor. The bending workability of both GW and BW exceeded 1.5.

In Comparative Example 7, the stress relieving annealing was performed, but since the tensile strength exceeded 5 MPa, the sheet thickness anisotropy became less than 1.0 and the drawing processability was poor. The bending workability of both GW and BW exceeded 1.5.

In Comparative Example 8, since the difference between the 0.2% proof stress after the final rolling and the 0.2% proof stress after the stress relieving annealing was less than 10, the plate thickness anisotropy (r) was less than 1.0 and the drawing processability was poor. The bending workability of both GW and BW exceeded 1.5.

Claims (4)

And a copper alloy having an electrical conductivity of 75% IACS or more and a 0.2% proof stress of 300 MPa or more and having a parallel direction and a right angle with respect to the rolling direction, (R) defined by (r ₀ + r ₉₀ + 2 x r ₄₅ ) / 4, where r ₀ , r ₉₀ and r ₄₅ are the respective rank pod values in the in- A copper alloy plate having a thickness of 1.0 or more. The method according to claim 1,
The ratio of the minimum bending radius (MBR) to the plate thickness (t) in the rolling parallel direction (GW direction) and the rolling right angle direction (BW direction) in the W bending test is set to MBR / . The method according to claim 1,
Further comprising 0.15% by mass or less in total of at least one selected from the group consisting of Ag, P, Co, Ni, Cr, Mn, Zn, Mg and Si. A heat dissipation electronic component comprising the copper alloy sheet according to any one of claims 1 to 3.