TWI607098B - Copper alloy plate and stamped product with copper alloy plate - Google Patents

Description

Copper alloy sheet and stamped product having copper alloy sheet

The present invention relates to a copper alloy sheet excellent in electrical conductivity, which is suitable for forming terminals, connectors, relays, switches, sockets, bus bars, lead frames and other electronic components of a given shape by punching (one of press processing). Etc., and a press-formed product having a copper alloy sheet, in particular, a technique for improving the punching property of a copper alloy sheet has been proposed.

Electronic components such as terminals, connectors, relays, switches, sockets, bus bars, lead frames, etc., which are assembled in motors and electronic equipment, for example, can be used to continuously feed long strips of copper alloy in one direction by using a continuous press die. The plate is formed into a press-formed product having a desired shape by sequentially performing press working by a punch and a lower die.

In the press-formed product formed by the press working as described above, the press-formed surface of the press-formed product punched by the punch is a sheared surface on the surface side in the thickness direction of the press-formed product, and is located on the back side. It is well known that the fracture surface is composed of two layers.

Further, the press-formed product in which the shearing surface occupies most of the punched section is likely to protrude toward the back side and form a burr. In the press-formed product used as an electronic component, when burrs are generated, the burr of the press-formed product assembled in the motor and the electronic device is likely to be short-circuited, which causes a failure, and in particular, in electronic component use. In the press-formed product, in order to suppress the generation of such burrs, a copper alloy sheet having improved stamping performance is required.

Stamping punchability in a copper alloy sheet surrounding such an electronic component Techniques such as improvement of the wear resistance of the mold and the like are described in Patent Documents 1 to 4.

Patent Document 1 describes a copper-nickel-bismuth (Cu-Ni-Si)-based copper alloy sheet material for use in a motor and an electronic device, in particular, by specifying a particle size of a compound dispersed in a copper alloy sheet material and dispersion thereof. The density is improved to obtain characteristics such as electroplating property, punchability, and heat resistance. Patent Document 2 discloses a copper-cobalt-ruthenium (Cu-Co-Si)-based copper alloy in which a precipitate having a particle diameter which promotes improvement in punchability is present on a surface layer which affects stamping properties. The precipitated material having a particle diameter that promotes the increase in strength exists in the intermediate portion where the strength is affected, and the wear of the mold can be reduced while maintaining the strength and the electrical conductivity. Patent Document 3 describes a copper alloy in which a certain amount of magnesium (Mg) and chromium (Cr) are added in order to maintain the excellent properties such as high strength, high electrical conductivity, heat resistance, and the like while further controlling mold wear caused by pressing. In particular, a given amount of lead (Pb) having a mold wear inhibiting the stamping is added.

Patent Document 4 describes a ratio of uniform elongation to total elongation obtained by a tensile test in a copper-iron-phosphorus (Cu-Fe-P)-based copper alloy sheet, that is, uniform elongation/total elongation The rate is less than 0.50. Further, as a result, the amount of ductile deformation of the material at the time of punching and punching is reduced, and the punching fracture occurs at an early stage, and the punching property is improved.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2008-95185

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2012-224922

[Patent Document 3] Japanese Patent Laid-Open Publication No. 8-13066

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2008-88499

However, in the above technique, the object is to improve stamping punchability by controlling the size and distribution of precipitates and inclusions, and adding elements, but there is no copper alloy composed of a copper-tin (Cu-Sn) alloy. The punching properties of the board are discussed for any purpose. Since the copper-tin alloy is a solid solution alloy, such a precipitate of the copper alloy of the prior art mentioned above does not exist, and in particular, a trace amount of tin is added to the oxygen-free copper. In the copper-tin alloy, the inclusions are also small due to the dissolution of the oxygen-free copper matrix.

Therefore, the punching property of the copper-tin alloy copper alloy sheet cannot be effectively improved by the above technique.

Further, as in Patent Document 4, since the characteristics of the copper alloy sheet can be changed by adjusting the uniform elongation and the total elongation, the other required characteristics of the surface properties such as burrs cannot be satisfied, and therefore, the maintenance cannot be required. Features to improve stamping and punching.

The present invention has been made to solve the above problems in the prior art, and an object of the invention is to provide a copper alloy plate of a copper-tin alloy as a solid solution alloy, which can effectively suppress generation of burrs after press working. A copper alloy sheet that improves stamping and punching, and a stamped product having a copper alloy sheet.

In order to reduce the proportion of the sheared surface which causes the occurrence of burrs and increase the proportion of the fracture surface in the press section of the press-formed product, the inventors act on the copper alloy sheet with an increase in the stroke of the press during the press working. The load changes were studied in depth.

As a result, a new discovery has been obtained: when a copper alloy sheet is produced, the crystal grain size at the time of final annealing is increased, and the ratio of the work roll diameter to the sheet thickness is controlled by finish rolling after final annealing, thereby increasing the workability. It is possible to effectively reduce the elongation in the thickness direction of the copper alloy sheet when sandwiched between the punch and the lower mold at the time of press working.

Moreover, it was found that the copper-tin alloy thus produced has no large change in tensile properties, and the half-value width of the displacement-load curve obtained in the shear test is smaller than that in the prior art, and copper is used in press working. The stamping section of the alloy sheet is formed at an early stage, and therefore, the generation of burrs can be effectively suppressed.

Based on such findings, the copper alloy sheet of the present invention contains 0.01 to 0.3% by mass of tin, and the balance is composed of copper and unavoidable impurities, and has a conductivity of 70% IACS (International Annealed Copper Standards) or higher. And the ratio of the half-width to the plate thickness (r) obtained from the displacement-load curve in the shear test is 0.2. r 0.7.

Among them, the copper alloy sheet of the present invention preferably has a conductivity of 75% IACS. As described above, the 0.2% of the undulation stress parallel to the rolling direction is 450 MPa or more, and the 0.2% of the undulation stress perpendicular to the rolling direction/0.2% of the undulation stress parallel to the rolling direction is 1.0 or more.

In the copper alloy sheet of the present invention, the ratio of the elongation perpendicular to the rolling direction and the elongation parallel to the rolling direction is preferably 0.8 or more and 1.2 or less.

Further, the copper alloy sheet of the present invention further contains a total amount of 0.1% by mass or less selected from the group consisting of phosphorus (P), silver (Ag), nickel (Ni), manganese (Mn), magnesium (Mg), and zinc (Zn). At least one element selected from the group consisting of boron (B) and calcium (Ca).

The press-formed product of the present invention has a copper alloy sheet of any of the above.

According to the present invention, the ratio of the half width to the thickness (r) obtained by the displacement-load curve in the shearing experiment is 0.2. r The copper alloy plate of 0.7 is formed at an early stage by the stamping section of the copper alloy plate held between the punch and the lower die at the time of press working, and a punched section having a large fracture surface ratio is formed, which can effectively suppress the generation of burrs. . Therefore, the stamping punchability can be greatly improved.

As a result, the copper alloy sheet is very suitable for terminals, connectors, relays, switches, sockets, bus bars, lead frames, and other electronic components.

Fig. 1 is a schematic view showing changes in the load acting on the copper alloy sheet in accordance with the state of the copper alloy sheet at each stage, and the increase in the stroke of the punch in the press working of the copper alloy sheet; Fig. 2 is a view of the present invention An example of a displacement-load curve of a copper alloy sheet according to an embodiment is compared with an example of a displacement-load curve of a copper alloy sheet in the prior art; and FIG. 3 is a graph for obtaining a displacement-load curve. A schematic view of a shear test; FIG. 4 is a microscopic image of a part of the fracture surface of Invention Example 1 magnified 100 times and 200 times, respectively; and FIG. 5 is a magnification of the fracture of Comparative Example 2 at 100 times and 200 times, respectively. Part of the face Microscope image.

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

The copper alloy sheet according to one embodiment of the present invention contains 0.01 to 0.3% by mass of tin, and the balance is composed of copper and unavoidable impurities, and has a conductivity of 70% IACS (International Annealing Copper Standard) or more, and is cut by The ratio of the half-width to the plate thickness (r) obtained by the displacement-load curve in the experiment is 0.2. r 0.7. Such a copper alloy sheet is suitable for an electronic component manufactured by press working.

(alloy composition concentration)

The tin concentration is 0.01 to 0.3% by mass. If the tin concentration exceeds 0.3% by mass, it is difficult to obtain a conductivity of 70% IACS or more. When the tin concentration is less than 0.01% by mass, the ratio (r) of the half width to the plate thickness obtained from the displacement-load curve in the shear test is 0.7 or more, and the effect of reducing the burrs cannot be confirmed. Further, if the tin concentration is less than 0.01% by mass, the required characteristics are not satisfied because the 0.2% drop stress is lowered. From this viewpoint, the tin concentration is preferably from 0.03 to 0.25 mass%, particularly preferably from 0.08 to 0.25 mass%.

In the copper-tin alloy of the present invention, in addition to tin, at least one element selected from the group consisting of phosphorus, silver, nickel, manganese, magnesium, zinc, boron, and calcium may be added, but when these elements are added The total amount of the added amount is preferably 0.1% by mass or less. When the total amount thereof exceeds 0.1% by mass, the electrical conductivity is lowered, the raw material cost is increased, and the manufacturability is deteriorated.

(Conductivity)

In the copper alloy sheet of the present invention, the conductivity measured by the JIS H0505 standard is 70% IACS or more. When the conductivity is 70% IACS or more, the required conductivity for a given electronic component can be exhibited. The conductivity is preferably 75% IACS or more, more preferably 80% IACS or more.

(0.2% relief stress)

In the present invention, parallel to the rolling direction of the copper alloy sheet (GW direction) The 0.2% of the lodging stress is preferably 450 MPa or more, and at this time, the copper alloy sheet sufficiently has the strength necessary as a material of the structural member. The 0.2% of the lodging stress parallel to the rolling direction is more preferably 500 MPa or more, and particularly preferably 520 MPa or more.

On the other hand, the 0.2% drop stress perpendicular to the rolling direction (BW) of the copper alloy sheet is preferably equal to or higher than the above-described 0.2% fall stress in the rolling direction. That is, the ratio of the 0.2% drop stress perpendicular to the rolling direction to the 0.2% fall stress parallel to the rolling direction is preferably 1.0 or more. This is because the length of the burrs after the press working can be shortened and the punchability can be improved. The ratio of the 0.2% drop stress perpendicular to the rolling direction/the 0.2% drop stress parallel to the rolling direction is more preferably 1.03 or more, further preferably 1.05 or more. On the other hand, if the ratio of the 0.2% drop stress perpendicular to the rolling direction / the 0.2% of the fall stress parallel to the rolling direction is too large, due to the stamped section parallel to the rolling direction and perpendicular to the rolling direction Anisotropy is generated, and the length of the burrs after pressing becomes long. Therefore, the ratio can be 1.2 or less, preferably 1.15 or less, more preferably 1.1 or less.

Further, a 0.2% drop stress was measured based on the JIS Z2241 standard.

(Half-width of the displacement-load curve)

The present inventors have studied the relationship between the punch stroke between the punch and the copper alloy plate and the load acting on the copper alloy plate in the press working of the copper alloy plate. As a result of intensive research, it was found that in the stamping section of the press-formed product obtained by press working, in order to reduce the proportion of the sheared section which causes the occurrence of burrs, and at the same time increase the proportion of the fracture surface, the shear test is reduced. The half-width of the displacement-load curve is valid.

This will be described in detail as follows. In the press working, as shown in the graph of Fig. 1, at the initial stage of the processing where the punch stroke is still small, the copper alloy plate sandwiched between the punch and the lower die is in contact with the punch and the lower die, respectively. A sag occurs. Thereafter, as the stroke of the punch increases, the copper alloy plate sandwiched between the punch and the lower die begins to form a shearing surface, and the punch and the lower die respectively bite into the copper alloy plate, and the respective collapses become cracks. The peak of the load is reached, and then, as the load decreases, the crack expands and forms a fracture surface.

Among them, the proportion of the sheared surface in the stamping section of the press-formed product increases Large: In the process of forming the stamping section from the surface and the back surface of the copper alloy sheet, the copper alloy sheet extends greatly in the thickness direction of the sheet without breaking, during which the punch cuts the copper alloy sheet. .

Therefore, in order to reduce the elongation in the thickness direction of the copper alloy sheet during the press working, the stamped section is quickly formed after the copper alloy sheet is collapsed, and it is thought that the displacement-load curve obtained by the shear test is obtained. The copper alloy sheet having a small half-peak width reduces the proportion of the sheared surface in the stamped section of the press-formed product, and the proportion of the fractured surface increases.

Based on the above findings, in the copper alloy sheet according to the embodiment of the present invention, the ratio of the half width to the sheet thickness (r) obtained from the displacement-load curve in the shear test is 0.2. r 0.7.

The displacement-load curve in the shear test, for example, as shown in Fig. 2, as the displacement increases, the load is a mountain-shaped curve that increases at an initial stage and falls after a peak. In the copper alloy sheet according to the embodiment of the present invention, the half width is a displacement width of a load of 1/2 of the load peak, and is smaller than a conventional copper alloy having the same thickness.

As a result, when the copper alloy sheet of the embodiment is subjected to press working, as shown in the first graph, the curve corresponding to the load of the punch stroke amount is collapsed on the front and back surfaces of the copper alloy sheet and after the peak is passed. The load is sharply lowered, and the press section is formed at an early stage, and the ratio of the shear plane caused by the punch cutting of the copper alloy sheet during the period until the formation of the press section can be effectively suppressed. Thereby, since the fracture surface is increased while the press section is reduced, the occurrence of the burrs protruding from the press section to the front and back sides can be effectively suppressed.

Here, the shear test for determining the displacement-load curve is performed as follows: As shown in Fig. 3, a sample of a copper alloy plate having a thickness of 0.1 mm is sandwiched between a cylindrical punch having a diameter of 9.98 mm and a gap is provided. The punch was displaced toward the lower mold at a speed of 0.1 mm/min between the lower molds of 0.01 mm, and the load was appropriately measured by a load cell provided on the punch side as the displacement was increased.

It is not necessary to specifically set the lower limit of the ratio (r) of the half width to the thickness of the sheet, but it is usually 0.2 or more in the case of forming the sag and the sheared section. On the other hand, if the ratio (r) of the half width to the thickness exceeds 0.7, the stamping addition cannot be sufficiently reduced. The elongation in the thickness direction of the working plate cannot be exerted as expected to suppress the occurrence of burrs.

Therefore, a better range of the ratio of the half width to the thickness of the plate (r) is 0.25. r<0.7, a further preferred range is 0.3 r<0.7.

(thickness)

The thickness of the copper alloy plate, that is, the thickness of the plate may be 0.05 mm to 2.0 mm. Since it is difficult to manage the punched sheared surface and the burr if it is outside the above range, the thickness is preferably from 0.06 mm to 1.5 mm. However, the thickness of the sheet can be appropriately determined depending on the use of the copper alloy sheet or the like, and is not limited to the numerical range shown in the present invention.

(elongation)

It is preferable that when the anisotropy of the elongation parallel to the rolling direction and the elongation perpendicular to the rolling direction is small, the press working can be performed in any direction, and the generation of the burrs can be suppressed. Therefore, the elongation perpendicular to the rolling direction and the elongation parallel to the rolling direction are preferably 0.8 or more and 1.2 or less. The ratio of the elongation perpendicular to the rolling direction to the elongation parallel to the rolling direction is more preferably 0.8 or more and 1.15 or less. The ratio of the elongation perpendicular to the rolling direction and the elongation parallel to the rolling direction is more preferably 0.8 or more and 1.1 or less. The elongation was measured based on the JIS Z2241 standard.

(flash height)

For the cylindrical test piece obtained after the above shear test, the punched section of the test piece was observed 360° using an optical microscope (magnification: 1000 times) and a stereoscopic microscope, and the length of the longest burr observed along the thickness direction of the plate was observed. As the height of the burr. The height of the burrs was measured in units of 1 μm, and if it was less than 5 μm, there was no problem in performance. It is preferably less than 3 μm, and it is further preferred to have no burrs.

(Production method)

The copper alloy sheet described above can be produced by the production method shown in the following example.

Oxygen-free copper or the like which is a raw material of pure copper is melted, tin and other alloying elements are added, and cast into an ingot having a thickness of about 30 to 300 mm. The ingot is formed into a plate having a thickness of about 3 to 30 mm by, for example, hot rolling at 800 to 1000 ° C. Thereafter, cold rolling and recrystallization annealing are repeated as many times as necessary, and the final product thickness is completed by final cold rolling. Finally, stress relief annealing is performed. Stress relief annealing does not need to be done intentionally. It does not affect the stamping properties.

In the recrystallization annealing, the rolled structure is recrystallized.

In particular, in the recrystallization annealing (final annealing) before 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 in the thickness direction of the copper alloy sheet produced during press working cannot be sufficiently reduced. That is, it is difficult to make the ratio of the half width of the displacement-load curve of the copper alloy sheet to the thickness of the plate (r) is 0.2. r 0.7. Therefore, the average particle diameter at the time of final annealing is preferably 50 μm or more, and particularly preferably 60 μm or more.

On the other hand, if the average particle diameter at the time of final annealing is too large, the 0.2% drop stress of the produced copper alloy sheet is lowered. Therefore, the average crystal grain size of the final annealing is preferably 100 μm or less, particularly 95 μm or less, and further 85 μm or less.

The conditions of the recrystallization annealing before the final cold rolling are determined according to the crystal grain size after the target annealing and the conductivity of the target article. Specifically, a batch furnace or a continuous annealing furnace may be used to anneal at a temperature of 550 to 850 ° C in the furnace. It is also possible to appropriately adjust the heating time in a batch furnace at a furnace temperature of 550 to 850 ° C in a range of 30 minutes to 30 hours. It is also possible to appropriately adjust the heating time in the continuous annealing furnace at a furnace temperature of 550 to 850 ° C for 5 seconds to 10 minutes.

In the final cold rolling (finishing), the material is repeatedly passed between a pair of rolls to achieve the target thickness.

Here, the number of passes between the rolls is set to n passes, and the degree of processing of each pass is set to the same size, and the diameter of the work roll and the plate of the material are set from the first pass to the n/3 pass or more. A thickness ratio of 40 or more is very important. By such calendering of the large-diameter work roll, since the contact area of the material with the work roll is large, the material can be largely compressed, and the half-width of the displacement-load curve of the manufactured copper alloy sheet can be effectively reduced. Among them, the total number of final cold rolling is 3 passes to 25 passes, preferably 5 passes to 15 passes.

After these passes, the final cold rolling degree of work Rf (%) is from Rf = (t _{0 -} t) / t ₀ × 100 (t ₀ : the thickness before the final cold rolling, t: the thickness after the final cold rolling )get. The degree of processing Rf of the final cold rolling is preferably 60% or more. That is, when the degree of work Rf of the final cold rolling is less than 60%, the 0.2% of the stress of the copper alloy is difficult to reach 450 MPa or more, and the required characteristics may not be sufficiently satisfied.

Further, the total degree of work R (%) of all cold rolling which is alternately repeated with recrystallization annealing is from R = (T _{0 -} T) / T ₀ × 100 (T ₀ : thickness before cold rolling, T: cold rolling After the plate thickness) is obtained. The total workability R is preferably 90% or more, more preferably 92% or more. When the total workability R is low, the ratio of the length of the copper alloy sheet perpendicular to the rolling direction/the length parallel to the rolling direction is less than 0.8. On the other hand, the upper limit of the total workability R of cold rolling is 99.5% or less. When it is more than 99.5%, the ratio of the length of the copper alloy sheet perpendicular to the rolling direction/the length parallel to the rolling direction is 1.2 or more. The total workability R may be 99.5% or less.

The stress relief annealing of the present invention is carried out using a continuous annealing furnace or a batch furnace. The heating conditions of any one are adjusted so that the temperature in the furnace is in the range of 300 to 600 ° C and the heating time is in the range of 5 seconds to 10 minutes. It is not necessary to deliberately perform stress relief annealing.

A feature of the present invention is that the ratio of the half width to the thickness (r) obtained by the displacement-load curve of the copper alloy sheet in the shearing test is within a given range, so that the copper during the press processing The elongation of the alloy sheet in the thickness direction becomes small, so that the stamped section is formed at an early stage. Therefore, the manufacturing conditions of the copper alloy sheet are as follows. a. The average crystal grain size at the time of final annealing was adjusted to 50 μm. b. In the initial pass of the final cold rolling, the work roll diameter/material thickness is 40 or more.

The copper alloy sheet manufactured as above can be processed into copper products of various thicknesses, for example, electronic components and other stampings for terminals, connectors, relays, switches, sockets, bus bars, lead frames, etc. formed by press working. In the molded product.

[Examples]

Next, the copper alloy sheet of the present invention was experimentally produced, and its performance was evaluated as described below. However, the description is for illustrative purposes only, and the invention is not limited thereto.

After the alloying element was added to the copper solution, an ingot having a thickness of 200 mm was cast. 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. The scale of the surface of the hot rolled sheet is ground by an internal grinding machine, and after being removed, annealing and cold rolling are repeated, and a given product thickness is obtained by final cold rolling. Finally, the stress relief annealing was performed using a continuous annealing furnace.

The final annealing (final recrystallization annealing) before cold rolling is to use a batch furnace, the heating time is set to 5 hours, and the temperature in the furnace is adjusted to be in the range of 300 to 700 ° C, so that the crystal grain size and electrical conductivity after annealing occur. Change. In the measurement of the crystal grain size after annealing, the mirror polishing was performed perpendicular to the cross section in the rolling direction, followed by chemical etching, and the average crystal grain size was determined by a cutting method (JIS H0501 (1999)).

According to each of the inventive examples and comparative examples shown in Table 1, the total degree of cold rolling, the degree of processing of the final cold rolling (finishing), the pass, and the diameter of the work rolls were adjusted.

The copper alloy sheets produced under the respective conditions were measured as follows.

(composition)

The concentration of the alloying elements was analyzed by ICP-mass spectrometry.

(shear test)

A sample having a thickness of 0.1 mm was taken, and the punch was turned downward at a speed of 0.1 mm/min in a state of being disposed between a cylindrical punch having a diameter of 9.98 mm and a lower die having a gap of 0.01 mm. The mode displacement is measured by the load cell provided on the punch side as the displacement increases, thereby calculating the half width from the obtained displacement-load curve.

(flash height)

The cross section formed around the cylindrical test piece obtained after the shear test was observed by an optical microscope (magnification: 1000 times) and a stereoscopic microscope, and the height of the burr was measured. The height of the burrs was measured in units of 1 μm.

(tensile strength and 0.2% stress)

According to the JIS Z2241 standard, test pieces were taken in a direction parallel to the rolling direction and a direction perpendicular to the rolling direction, and tensile strength and 0.2% lodging stress were obtained by performing tensile tests in various directions.

(elongation)

According to the JIS Z2241 standard, test pieces were taken in a direction parallel to the rolling direction and a direction perpendicular to the rolling direction, and the distance between the punctuation points was 50 mm, and the elongation in each direction was measured.

(Conductivity)

The test piece was taken from the copper alloy plate in the longitudinal direction of the test piece in parallel with the rolling direction, and the electrical conductivity at 20 ° C was measured by a four-terminal method based on the JIS H0505 standard.

The respective conditions of the inventive examples and comparative examples are shown in Table 1, and the measured results are shown in Table 2.

[Table 1]

[Table 2]

As shown in Tables 1 and 2, it was found that the average crystal grain size at the time of final annealing in Inventive Examples 1 to 23 was 50 μm or more, and the thickness of the work roll/material was 40 or more. The ratio of the half-width to the plate thickness (r) of the displacement-load curve of the copper alloy plate is 0.2. r At 0.7, the height of the burr was 5 or less, and thus a product having good stamping properties was obtained. Further, in Inventive Examples 1 to 23, since the electrical conductivity of the copper alloy sheet was 70% IACS or more, the electrical conductivity required for application to an electronic component or the like was satisfied.

On the other hand, in Comparative Example 1, when the amount of addition of tin is as small as 0.007% by mass, the ratio (r) of the half-value width to the thickness of the copper alloy sheet becomes large, and the burr The height has also increased.

In Comparative Examples 2 and 5, the final annealing temperature was lowered, and the average crystal grain size at the final annealing was small, but as a result, the ratio (r) of the half-value width to the plate thickness of the copper alloy sheet became large, although not as in Comparative Example 1. It is as high as it is, but the height of the raw edge is also high.

In Comparative Examples 3 and 6, in the initial stage of the final cold rolling, since the work roll diameter/material thickness was small, the ratio of the half width of the copper alloy plate to the plate thickness (r) became large, and the height of the burrs also changed. Taller.

In Comparative Example 4, by reducing the number of initial passes in the finish rolling in which the diameter of the work roll is increased, since the material cannot be sufficiently rolled by the large-diameter work roll, the ratio of the half width of the copper alloy plate to the thickness of the plate (r ) It becomes bigger and the height of the burrs becomes higher.

Further, in Comparative Example 7, although the ratio (r) of the half width of the copper alloy sheet to the thickness of the copper alloy sheet was within a given range, the amount of addition of P was increased to cause a decrease in electrical conductivity.

Therefore, with the copper alloy sheet of the present invention, the generation of burrs can be effectively suppressed, and the punching property can be improved.

Claims (5)

A copper alloy plate containing 0.01 to 0.3% by mass of tin, the balance being composed of copper and unavoidable impurities, having a conductivity of 70% IACS or more, and obtained from a displacement-load curve in a shear test The ratio of the half width to the plate thickness (r) is 0.2. r 0.7. The copper alloy sheet according to claim 1, wherein the electrical conductivity is 75% IACS or more, the 0.2% of the lodging stress parallel to the rolling direction is 450 MPa or more, and the 0.2% drop perpendicular to the rolling direction. The stress/0.2% of the lodging stress parallel to the rolling direction is 1.0 or more. The copper alloy sheet according to the first aspect of the invention, wherein the ratio of the elongation perpendicular to the rolling direction and the elongation parallel to the rolling direction is 0.8 or more and 1.2 or less. The copper alloy sheet according to claim 1, wherein the total amount is at least 0.1% by mass or less selected from the group consisting of phosphorus, silver, nickel, manganese, magnesium, zinc, boron, and calcium. An element. A press-formed article having a copper alloy sheet according to any one of claims 1 to 4.