JP6085633B2 - Copper alloy plate and press-molded product including the same - Google Patents

Description

  The present invention relates to a copper alloy plate excellent in electrical conductivity suitable for use in terminals, connectors, relays, switches, sockets, bus bars, lead frames, and other electronic parts manufactured by press working in a predetermined shape, and the like In particular, it proposes a technique capable of improving the press punchability of a copper alloy plate.

  Electronic parts such as terminals, connectors, relays, switches, sockets, bus bars, lead frames, etc., incorporated in electrical and electronic equipment, etc., are long lengths that are sent intermittently in one direction using, for example, a progressive press die The belt-shaped copper alloy plate may be manufactured as a press-molded product that is formed into a desired shape by sequentially performing press processing using a punch and a die.

  Here, in the press-molded product formed by the press work as described above, the press fracture surface of the press-molded product punched out by the punch has a shear surface located on the front side in the thickness direction of the press-molded product, and the back surface side. It is generally known to be composed of two layers of fractured surfaces located at

  Of these, the press-molded product in which the shear surface occupies most of the press fracture surface is likely to generate burrs formed with the shear surface protruding to the back surface side. When a burr occurs in a press-molded product used as an electronic component, the burr of the press-molded product built into an electric machine / electronic device can cause a short circuit and can cause a failure. In press molded products for use in electronic parts, a copper alloy sheet with improved press punchability is desired to suppress the occurrence of such burrs.

Examples of such a copper alloy plate for electronic components, which focus on improvement of press punchability and wear resistance of a mold, include those described in Patent Documents 1 to 4.
In Patent Document 1, in a Cu—Ni—Si based copper alloy sheet material used for electrical and electronic equipment, by defining the particle size of the compound dispersed in the copper alloy sheet material and its dispersion density, in particular, the plating property, press Improvement of properties such as heat resistance and heat resistance is described. In Patent Document 2, a precipitate having a particle size that contributes to improvement in press punchability is present in a surface layer that affects press punchability, and a precipitate having a particle size that contributes to improvement in strength is present in the central portion that affects strength. Cu—Co—Si based copper alloys that can reduce mold wear while maintaining strength and electrical conductivity are disclosed. In Patent Document 3, while maintaining excellent properties such as high strength, high conductivity and heat resistance, and further suppressing mold wear due to stamping, Mg, Cr is added in a predetermined amount, A copper alloy obtained by adding a predetermined amount of Pb having an action of suppressing stamping mold wear is described.

  Patent Document 4 describes that, in a Cu—Fe—P-based copper alloy plate, the ratio of uniform elongation to total elongation and uniform elongation / total elongation obtained by a tensile test are less than 0.50. And according to this, the amount of ductile deformation of the material at the time of press punching is reduced, the punching breakage occurs at an early stage, and the press punchability is improved.

JP 2008-95185 A JP 2012-224922 A JP-A-8-13066 JP 2008-88499 A

However, in the above-described technique, the size and distribution of precipitates and inclusions are controlled, and the press punchability is improved by an additive element. However, the press punchability of a copper alloy plate made of a Cu-Sn alloy is considered. Has not been studied at all. Since the Cu—Sn alloy is a solid solution type alloy, there is no precipitate such as the copper alloy noted in the above prior art, and in particular, Cu— In the Sn alloy, since it is an oxygen-free copper-based melt, there are few inclusions.
Therefore, the press punchability of the Cu—Sn alloy copper alloy sheet cannot be effectively improved by the above-described technique.

  Further, as in Patent Document 4, the method of adjusting the uniform elongation and the total elongation changes the characteristics of the copper alloy plate, and therefore does not satisfy other required characteristics of the surface properties such as burrs. Therefore, it is not possible to improve the press punchability while maintaining the required characteristics.

  The object of the present invention is to solve the above-mentioned problems of the prior art described above, and the object of the invention is a copper alloy plate of a Cu—Sn alloy, which is a solid solution type alloy, and press. An object of the present invention is to provide a copper alloy plate capable of effectively suppressing the occurrence of burrs after processing and improving press punchability, and a press-molded product including the same.

The inventor reduces the ratio of the shear plane that causes burrs and increases the ratio of the fracture surface in the press fracture surface of the press-formed product, so that it acts on the copper alloy plate as the punch stroke increases during press processing. We studied diligently about the change of load.
As a result, when producing a copper alloy sheet so that the elongation in the thickness direction of the copper alloy sheet when sandwiched between a punch and a die during press working is reduced, the crystal grain size at the time of final annealing is set. We obtained new knowledge that it is effective to increase the degree of processing by controlling the ratio of the work roll diameter to the plate thickness in the finish rolling after final annealing.

  And in the Cu-Sn alloy manufactured thereby, the half-value width of the displacement-load curve obtained by the shear test is smaller than that of the conventional one, without greatly changing the tensile properties. It was found that the generation of burrs can be effectively suppressed by forming the press fracture surface on the copper alloy plate at an early stage during processing.

  Based on such knowledge, the copper alloy sheet of the present invention contains 0.01 to 0.3% by mass of Sn, the balance is made of copper and its inevitable impurities, and has a conductivity of 70% IACS or higher. In addition, the ratio (r) of the half width obtained from the displacement-load curve in the shear test to the plate thickness is 0.2 ≦ r ≦ 0.7.

Here, in the copper alloy sheet of the present invention, the electrical conductivity is 75% IACS or more, the 0.2% proof stress in the rolling parallel direction is 450 MPa or more, and the 0.2% proof stress in the direction perpendicular to the rolling / the rolling parallel direction. The 0.2% proof stress is preferably 1.0 or more.
Here, in the copper alloy sheet of the present invention, the ratio of the elongation in the direction perpendicular to the rolling to the elongation in the rolling parallel direction is preferably 0.8 or more and 1.2 or less.

  The copper alloy plate of the present invention further contains at least one element selected from the group consisting of P, Ag, Ni, Mn, Mg, Zn, B and Ca in a total amount of 0.1% by mass or less. It can be.

  The press-formed product of the present invention includes any one of the above-described copper alloy plates.

According to the present invention, the ratio of the half width obtained from the displacement-load curve in the shear test to the plate thickness (r) is a copper alloy plate in which 0.2 ≦ r ≦ 0.7. At times, a press fracture surface is formed early on a copper alloy plate sandwiched between a punch and a die, so that the ratio of fracture surface becomes a large press fracture surface and effectively suppresses the generation of burrs. Can do. Thereby, the press punchability can be greatly improved.
As a result, this copper alloy plate can be suitably used for terminals, connectors, relays, switches, sockets, bus bars, lead frames and other electronic components.

It is a graph which shows typically the change of the load which acts on a copper alloy plate with the increase in the punch stroke at the time of press processing of a copper alloy plate with the state of the copper alloy plate of each step. It is a graph which shows typically an example of the displacement-load curve of the copper alloy plate concerning one embodiment of this invention compared with an example of the displacement-load curve of the conventional copper alloy plate. It is a figure which shows roughly the shear test for calculating | requiring a displacement-load curve. It is a microscope picture which shows a part of fracture surface of the example 1 of an invention by each magnification of 100 time and 200 times. It is a microscope picture which shows a part of fracture surface of the comparative example 2 with each magnification of 100 time and 200 times.

Hereinafter, embodiments of the present invention will be described in detail.
A copper alloy plate according to an embodiment of the present invention is composed of a Cu-Sn alloy containing 0.01 to 0.3% by mass of Sn and the balance being made of copper and its inevitable impurities. And having a conductivity of 70% IACS or more and a ratio (r) of a half width obtained from a displacement-load curve in a shear test to a plate thickness is 0.2 ≦ r ≦ 0.7 It is. Such a copper alloy plate is suitable for applications of electronic parts manufactured by press working.

(Alloy component concentration)
Sn concentration shall be 0.01-0.3 mass%. If the Sn concentration exceeds 0.3% by mass, it becomes difficult to obtain a conductivity of 70% IACS or more. When the Sn concentration is less than 0.01% by mass, the ratio (r) of the half width obtained from the displacement-load curve in the shear test to the plate thickness becomes 0.7 or more, and no burr reduction effect is observed. On the other hand, when the Sn concentration is less than 0.01% by mass, the 0.2% proof stress is lowered, which is not desirable from the viewpoint of satisfying the required characteristics. From such a viewpoint, the Sn concentration is preferably 0.03 to 0.25% by mass, and particularly preferably 0.08 to 0.25% by mass.

  In the Cu—Sn based alloy of this invention, in addition to Sn, at least one element selected from the group consisting of P, Ag, Ni, Mn, Mg, Zn, B and Ca can be added. When such elements are added, the total amount is preferably 0.1% by mass or less. When the total of these exceeds 0.1% by mass, the electrical conductivity is lowered, the raw material cost is increased, or the productivity is deteriorated.

(conductivity)
In the copper alloy plate of the present invention, the conductivity measured in accordance with JIS H0505 is 70% IACS or more. If the electrical conductivity is 70% IACS or higher, the required electrical conductivity when used in a predetermined electronic component can be exhibited. The conductivity is preferably 75% IACS or more, more preferably 80% IACS or more.

(0.2% yield strength)
In this invention, it is preferable that the 0.2% proof stress in the rolling parallel direction (GW direction) of the copper alloy plate is 450 MPa or more. In this case, the copper alloy plate has sufficient strength necessary as a material for the structural material. It can be said that. The 0.2 proof stress in the rolling parallel direction is more preferably 500 MPa or more, and particularly preferably 520 MPa or more.

On the other hand, it is preferable that the 0.2% yield strength of the copper alloy sheet in the direction perpendicular to the rolling direction (BW direction) is not less than the 0.2% yield strength in the rolling parallel direction described above. That is, the ratio of the 0.2% proof stress in the direction perpendicular to the rolling to the 0.2% proof stress in the rolling parallel direction is preferably 1.0 or more. This is because the length of the burr after press working is shortened and the pressability is improved. The ratio of 0.2% yield strength in the direction perpendicular to rolling / 0.2% yield strength in the parallel direction of rolling is more preferably 1.03 or more, and further preferably 1.05 or more. On the other hand, if the ratio of 0.2% yield strength in the direction perpendicular to rolling / 0.2% yield strength in the direction parallel to rolling is too large, anisotropy will occur on the fracture surface after pressing in the direction parallel to rolling and in the direction perpendicular to rolling. As a result, since the burr length after pressing becomes long, this ratio can be made 1.2 or less, preferably 1.15 or less, more preferably 1.1 or less.
The 0.2% proof stress is measured based on JIS Z2241.

(Displacement-half width of load curve)
The inventor has earnestly studied the relationship between the punch stroke from when the punch touches the surface of the copper alloy plate until the copper alloy plate is punched and the load acting on the copper alloy plate during the pressing of the copper alloy plate. As a result of the examination, in order to reduce the ratio of shear planes that cause burrs and increase the ratio of fractured surfaces in the press fracture surface of press-molded products obtained by press working, the displacement-load curve in the shear test is used. It has been found that it is effective to reduce the required half width.

This is explained in detail as follows. At the time of press working, as schematically illustrated in the graph of FIG. 1, at the initial stage of processing where the punch stroke is still small, each of the punch and the die contacts the copper alloy plate sandwiched between the punch and the die. Sagging occurs at the point where it is done. Next, as the punch stroke increases, a shear surface begins to be formed on the copper alloy plate between the punch and the die, and each of the punch and the die further bites into the copper alloy plate, and each of the above sagging becomes a crack. The peak of the load is reached, and then the crack propagates and a fracture surface is formed as the load decreases.
Here, the ratio of the shearing surface to the press fracture surface of the press-formed product increases because the copper alloy plate is dipped on the surface and the back surface until the press fracture surface is formed. It is considered that the alloy plate is not torn and extends greatly in the thickness direction, and the punch cuts the copper alloy plate in the meantime.

  Therefore, the displacement-load curve in the shear test is used so that the fracture in the thickness direction of the copper alloy plate during press working is reduced and the fracture surface is formed immediately after the copper alloy plate is sagged. It was thought that by using a copper alloy plate having a small half-value width obtained from the above, the ratio of the shear surface to the press fracture surface of the press-formed product decreases and the ratio of the fracture surface increases.

Based on such knowledge, in the copper alloy plate of the embodiment of the present invention, the ratio (r) of the half width obtained from the displacement-load curve in the shear test to the plate thickness is 0.2 ≦ r ≦ 0.7. To do.
For example, as shown in FIG. 2, the displacement-load curve in the shear test is a mountain-shaped curve that increases in the initial stage but decreases after passing through the peak as the displacement increases. In the copper alloy plate of the embodiment, the half width, which is a displacement width of a load that is half the peak load, is smaller than that of a conventional copper alloy plate having the same thickness.

  As a result, when the copper alloy plate of this embodiment is subjected to press working, sagging is formed on the front and back surfaces of the copper alloy plate in a load curve with respect to the punch stroke amount as shown in FIG. After the peak, the load decreases rapidly and a press fracture surface is formed at an early stage.Therefore, the punch is caused by scraping the copper alloy plate before the press fracture surface is formed. An increase in the ratio of the cross section can be effectively suppressed. As a result, the shear surface becomes smaller and the fracture surface becomes larger at the press fracture surface, so that it is possible to effectively suppress the generation of burrs protruding from the press fracture surface to the front and rear surfaces.

  Here, as shown in FIG. 3, the shear test for obtaining the displacement-load curve was performed using a copper alloy plate sample with a thickness of 0.1 mm, a cylindrical punch with a diameter of 9.98 mm, and a clearance of 0. The punch can be sandwiched between dies provided at 01 mm, and the punch is displaced toward the die at a speed of 0.1 mm / min. As the displacement increases, the load can be appropriately measured with a load cell provided on the punch side. .

Although the lower limit of the ratio of the half width to the plate thickness (r) is not particularly set, it is usually 0.2 or more when a sag and a shear surface are formed. On the other hand, if the ratio of the half width to the plate thickness (r) exceeds 0.7, the elongation in the plate thickness direction during press working is not sufficiently reduced, so that the effect of suppressing the generation of burrs is obtained. Can't perform as well as expected.
Therefore, a more preferable range of the ratio (r) of the half width to the plate thickness is 0.25 ≦ r <0.7, and a further preferable range is 0.3 ≦ r <0.7.

(Thickness)
Specifically, the thickness of the copper alloy plate, that is, the plate thickness can be set to 0.05 mm to 2.0 mm. Outside the above range, since the difficulty of managing the shear plane and burrs of the press becomes high, a more preferable plate thickness is 0.06 mm to 1.5 mm. However, the plate thickness is appropriately determined according to the use of the copper alloy plate and the like, and is not limited to the numerical range exemplified here.

(Elongation)
It is preferable that the anisotropy between the elongation in the rolling parallel direction and the elongation in the direction perpendicular to the rolling is smaller in that it is possible to suppress the generation of burrs, even when pressing is performed in any direction. Therefore, the ratio of the elongation in the direction perpendicular to the rolling to the elongation in the rolling parallel direction is preferably 0.8 or more and 1.2 or less. The ratio of the elongation in the direction perpendicular to the rolling to the elongation in the rolling parallel direction is more preferably from 0.8 to 1.15, and even more preferably from 0.8 to 1.1. This elongation is measured according to JIS Z2241.

(Burr height)
About the cylindrical test piece obtained after the above shear test, the entire press fracture surface of the test piece was observed over 360 ° using an optical microscope (magnification 1000 times) and a stereomicroscope, and was the longest observed. The length along the thickness direction of the burr was defined as the burr height. The burr height is measured in units of 1 μm, and if it is less than 5 μm, there is no functional problem. Preferably it is less than 3 μm, more preferably no burr.

(Production method)
The copper alloy plate described above can be manufactured by a manufacturing method shown as an example below.
Oxygen-free copper or the like is dissolved as a pure copper raw material, Sn and other alloy elements are added as necessary, and cast into an ingot having a thickness of about 30 to 300 mm. After this ingot is made into a plate having a thickness of about 3 to 30 mm by hot rolling at 800 to 1000 ° C., for example, cold rolling and recrystallization annealing are repeated a predetermined number of times as necessary, and the final cold rolling is performed. Finish to a predetermined product thickness and finally apply strain relief annealing. There is no influence on the pressability even if the strain relief annealing is not particularly performed.

In recrystallization annealing, the rolled structure is recrystallized.
In particular, here, in the recrystallization annealing (final annealing) before the final cold rolling, the average crystal grain size of the material is adjusted to 50 μm or more. If the average crystal grain size at this time is too small, the elongation of the produced copper alloy plate in the thickness direction during press working cannot be made sufficiently small. In other words, it becomes difficult to set the ratio (r) of the half-value width of the displacement-load curve of the copper alloy plate to 0.2 ≦ r ≦ 0.7. For this reason, the average crystal grain size at the time of final annealing is more preferably 50 μm or more, and particularly preferably 60 μm or more.
On the other hand, when the average crystal grain size at the time of final annealing is too large, the 0.2% yield strength of the manufactured copper alloy sheet is lowered. Therefore, the average crystal grain size during the final annealing is preferably 100 μm or less, more preferably 95 μm or less, and even more preferably 85 μm or less.

  The conditions for recrystallization annealing before the final cold rolling are determined based on the target crystal grain size after annealing and the target product conductivity. Specifically, annealing may be performed using a batch furnace or a continuous annealing furnace and setting the furnace temperature to 550 to 850 ° C. In a batch furnace, the heating time may be appropriately adjusted within the range of 30 minutes to 30 hours at a furnace temperature of 550 to 850 ° C. In a continuous annealing furnace, the heating time may be appropriately adjusted within a range of 5 seconds to 10 minutes at a furnace temperature of 550 to 850 ° C.

In the final cold rolling (finish rolling), the material is repeatedly passed between a pair of rolling rolls to finish the target plate thickness.
Here, if the number of passes between the rolling rolls is n passes, the processing degree of each pass is set to the same size, and n / 3 passes or more from the first pass is the diameter of the work roll relative to the thickness of the material. It is important that the ratio is 40 or more. By rolling with such a large-diameter work roll, the material is greatly compressed due to the large contact area of the work roll with the material, and the displacement-load curve of the produced copper alloy sheet The half width of can be effectively reduced. Here, the total number of passes of the final cold rolling is 3 to 25 passes, preferably 5 to 15 passes.

Thus, the workability Rf (%) of the final cold rolling performed over a plurality of passes is Rf = (t ₀ −t) / t ₀ × 100 (t ₀ : plate thickness before final cold rolling, t: final cold (Thickness after cold rolling). The workability Rf of this final cold rolling is preferably 60% or more. In other words, when the workability Rf of the final cold rolling is less than 60%, it is difficult to make the 0.2% proof stress of the copper alloy 450 MPa or more, and the required characteristics may not be sufficiently satisfied. .

Moreover, the total workability R (%) of the entire cold rolling repeated alternately with recrystallization annealing is R = (T ₀ −T) / T ₀ × 100 (T ₀ : plate thickness before cold rolling, T : Thickness after cold rolling). The total processing degree R is preferably 90% or more, and more preferably 92% or more. When the total workability R is low, the ratio of elongation in the direction perpendicular to the rolling / elongation in the direction parallel to the rolling of the copper alloy sheet is less than 0.8. On the other hand, the upper limit of the total workability R of cold rolling can be 99.5% or less. When it is larger than 99.5%, the elongation in the direction perpendicular to the rolling / elongation in the rolling parallel direction of the copper alloy sheet is 1.2 or more. The total processing degree R can be 99.5% or less.

  The strain relief annealing of the present invention is performed using a continuous annealing furnace or a batch furnace. In all cases, the heating conditions are adjusted in the range of 300 to 600 ° C. for 5 seconds to 10 minutes. The strain relief annealing is not particularly required.

In the present invention, the half-value width obtained from the displacement-load curve of the copper alloy plate so that the elongation in the thickness direction of the copper alloy plate during press working is reduced and the formation of the press fracture surface is made early. One characteristic is that the ratio (r) to the plate thickness is within a predetermined range. The manufacturing conditions of the copper alloy plate for that purpose are as follows.
a. The average grain size during final annealing is adjusted to 50 μm or more.
b. In the initial pass of the final cold rolling, the work roll diameter / material thickness is set to 40 or more.

  The copper alloy plates manufactured as described above are processed into copper products having various thicknesses, such as terminals, connectors, relays, switches, sockets, bus bars, lead frames, etc., formed by pressing. Suitable for use in electronic parts and other press-formed products.

  Next, the copper alloy plate of the present invention was prototyped and its performance was evaluated and will be described below. However, the description here is for illustrative purposes only and is not intended to be limiting.

  After adding the alloy element to the molten copper, it was cast into an ingot having a thickness of 200 mm. The ingot was heated at 800 ° C. for 3 hours, and hot rolled at 800 ° C. to form a plate having a thickness of 16 mm. After grinding and removing the oxide scale on the surface of the hot rolled sheet with a grinder, annealing and cold rolling were repeated, and the product was finished to a predetermined product thickness by final cold rolling. Finally, strain relief annealing was performed using a continuous annealing furnace.

  Annealing before final cold rolling (final recrystallization annealing) uses a batch furnace, adjusts the furnace temperature in the range of 300 to 700 ° C. with a heating time of 5 hours, and sets the crystal grain size and conductivity after annealing. Changed. In the measurement of the crystal grain size after annealing, a cross section perpendicular to the rolling direction was subjected to chemical corrosion after mirror polishing, and the average crystal grain size was determined by a cutting method (JIS H0501 (1999)).

As shown in Table 1, the total degree of cold rolling, the degree of final cold rolling (finish rolling), the number of passes, and the diameter of the work roll were changed and controlled in each invention example and comparative example.
The following measurement was performed with respect to the copper alloy plate manufactured under each condition.

(component)
The alloy element concentration was analyzed by ICP-mass spectrometry.

(Shear test)
A sample with a thickness of 0.1 mm was taken and punched at a speed of 0.1 mm / min in a state where it was placed between a cylindrical punch with a diameter of 9.98 mm and a die with a clearance of 0.01 mm. The half width was calculated from the obtained displacement-load curve by measuring the load with a load cell provided on the punch side as the displacement increased.

(Burr height)
The press fracture surface formed around the cylindrical test piece after the shear test was observed over the entire circumference using an optical microscope (magnification 1000 times) and a stereomicroscope, and the height of the burr was measured. The height of the burr was measured in units of 1 μm.

(Tensile strength and 0.2% yield strength)
In accordance with JIS Z2241, each test piece was sampled in a direction parallel to the rolling direction and a direction perpendicular to the rolling direction, and a tensile test in each direction was performed. .2% yield strength was determined.

(Elongation)
Based on JIS Z2241, each test piece was extract | collected in the direction along each of the direction parallel to a rolling direction, and the direction orthogonal to a rolling direction, and the elongation of each direction was measured as the distance between gauge points of 50 mm.

(conductivity)
The conductivity was measured by taking a test piece from a copper alloy plate so that the longitudinal direction of the test piece was parallel to the rolling direction, and measuring 20 ° C. by a four-terminal method in accordance with JIS H0505.

  Table 1 shows the conditions of the invention and comparative examples, and Table 2 shows the results obtained by the measurement.

  As shown in Tables 1 and 2, in each of Invention Examples 1 to 23, the average crystal grain size at the time of final annealing was set to 50 μm or more, and the work roll diameter / material thickness was set to 40 or more. The ratio (r) of the half width obtained from the displacement-load curve of the copper alloy plate to the plate thickness is 0.2 ≦ r ≦ 0.7, and the burr height is 5 or less and the press punching property is good. It became a thing. In Invention Examples 1 to 23, since the conductivity of the copper alloy plate was 70% IACS or more, the conductivity required when used for electronic parts was satisfied.

On the other hand, in Comparative Example 1, since the amount of Sn added was as small as 0.007% by mass, the ratio (r) of the half width of the copper alloy plate to the plate thickness was increased, and the burr height was also increased. It was.
In Comparative Examples 2 and 5, as a result of the final annealing temperature being low and the average crystal grain size at the time of final annealing being small, the ratio (r) of the half-value width of the copper alloy plate to the plate thickness was increased. Although not as high as in Example 1, the burr height was high.

In Comparative Examples 3 and 6, since the work roll diameter / material thickness was small in the initial pass of the final cold rolling, the ratio (r) of the half-value width to the thickness of the copper alloy sheet increased, The height has increased.
In Comparative Example 4, since the number of initial passes in which the work roll diameter was increased by finish rolling was small, the material was not sufficiently rolled by the work roll having a large diameter. The ratio (r) to the plate thickness was increased, and the burr height was increased.
In Comparative Example 7, the ratio (r) of the half width of the copper alloy plate to the plate thickness was within a predetermined range, but the conductivity decreased due to the large amount of P added. It was.

  From the above results, it was found that according to the copper alloy plate of the present invention, the generation of burrs can be effectively suppressed and the press punchability can be improved.

Claims (5)

0.01 to 0.3% by mass of Sn, with the balance being copper and its inevitable impurities,
Copper alloy sheet having a conductivity of 70% IACS or more and a ratio (r) of a half width obtained from a displacement-load curve in a shear test to a sheet thickness of 0.2 ≦ r ≦ 0.7 .   Conductivity is 75% IACS or more, 0.2% proof stress in the rolling parallel direction is 450 MPa or more, and 0.2% proof stress in the direction perpendicular to rolling / 0.2% proof stress in the rolling parallel direction is 1.0 or more. The copper alloy plate according to claim 1.   The copper alloy sheet according to claim 1 or 2, wherein a ratio of elongation in the direction perpendicular to the rolling to elongation in the rolling parallel direction is 0.8 or more and 1.2 or less.   The at least 1 sort (s) of the element chosen from the group which consists of P, Ag, Ni, Mn, Mg, Zn, B, and Ca is further contained at a total of 0.1 mass% or less, The any one of Claims 1-3 further containing. Copper alloy plate.   A press-molded article comprising the copper alloy plate according to any one of claims 1 to 4.