CN114867875A - Copper alloy sheet material, method for producing same, and member for electric/electronic component - Google Patents

Abstract

The copper alloy sheet material had the following alloy composition: contains 0.10-0.80 mass% of Cr, the balance being Cu and unavoidable impurities, a tensile strength of 350-800MPa, an electrical conductivity of 55-90% IACS, and a cross section S cut in a 0 DEG direction with respect to the rolling direction _0° Average crystal grain diameter A in the thickness direction of the sheet _0° A section S cut in the direction of 45 DEG _45° Average crystal grain diameter A in the thickness direction of the sheet _45° And a cross section S cut in the direction of 90 DEG _90° Average crystal grain diameter A in the thickness direction of the sheet _90° All are 10.0 μm or less, and A _0° Standard deviation of (A) _45° Standard deviation of (A) and _90° has an average value of standard deviation of 2.0 μm or less, and the average crystal grain diameter A represented by the following formula (1) _0° Degree of anisotropy B of _0° And the average crystal grain diameter A _45° Degree of anisotropy B of _45° And the average crystal grain diameter A _90° Degree of anisotropy B of _90° All of them are 10.0% or less. Wherein in the formula (1), m is 0 °, 45 ° or 90 °, and C is A _0° 、A _45° And A _90° Average value of (A) ((A) _0° +A _45° +A _90° )/3)。B _m ＝100×(A _m -C)/C … … formula (1).

Description

Copper alloy sheet material, method for producing same, and member for electric/electronic component

Technical Field

The present invention relates to a copper alloy sheet material, a method for producing the same, and a member for electric and electronic components.

Background

Generally, a copper alloy sheet material used for connectors for electronic devices, shield cases for automobile mounting, and the like is subjected to press working such as punching, bending, drawing, bulging, and the like, and burring (hole flanging).

In addition, it is required to simultaneously realize at a higher level: mechanical properties and electrical properties of copper alloy sheet materials used for electrical and electronic component members constituting electrical and electronic devices, along with recent high performance of electronic devices and automobile-mounted devices; and workability of the copper alloy sheet material into a desired shape, which is accompanied by weight reduction and formation of a complicated shape of the member for electric and electronic components.

For example, patent document 1 describes a copper alloy sheet containing 0.1 to 0.6 mass% of Cr, 0.01 to 0.30 mass% in total of 1 or 2 kinds of Zr and Ti, and the balance consisting of copper and unavoidable impurities, wherein the number of phase 2 particles having a particle size of 0.1 μm or more among phase 2 particles present in a matrix is 1000 to 10000000 particles/mm ² The method of (1) exists.

In patent document 1, the number of particles of phase 2 of the Cu — Cr alloy is controlled, thereby achieving high strength, high conductivity, and bending workability. However, since the burring process for enlarging a circular hole is completely different from the bending process, the burring workability is insufficient in the copper alloy sheet of which the number of particles of the 2 nd phase of the Cu — Cr alloy is controlled as in patent document 1.

Further, the copper alloy sheet material produced by the conventional method can be subjected to burring under difficult conditions, but mechanical properties and electrical properties need to be sacrificed. The difficult-to-handle processing includes, for example: in order to increase the hole flange height of the flanging processing hole, the hole expansion rate of the flanging processing hole is increased; in order to shorten the punch stroke and improve the productivity, the angle of the front end of the hole-expanding punch is increased relative to the punch stroke; and so on.

As described above, there has been demanded a copper alloy sheet material which has excellent burring workability even if burring is performed under difficult conditions in the course of working into a target shape, without sacrificing the balance between strength and electrical conductivity required for recent members for electric and electronic components.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-154910

Disclosure of Invention

Problems to be solved by the invention

The invention aims to provide a copper alloy sheet material, a manufacturing method thereof and a member for electric and electronic components, wherein the copper alloy sheet material has sufficient strength and conductivity and excellent flanging processability even if flanging is performed under difficult-to-machine conditions.

Means for solving the problems

The gist of the present invention is as follows.

[1] A copper alloy sheet material characterized by having the following alloy composition: contains 0.10 to 0.80 mass% of Cr, and the balance of Cu and unavoidable impurities,

a tensile strength of 350MPa to 800MPa, an electrical conductivity of 55% to 90% IACS,

a cross section S cut in the direction of 0 DEG with respect to the rolling direction _0° Average crystal grain diameter A in the thickness direction of the sheet _0° A section S cut in the direction of 45 DEG _45° Average crystal grain diameter A in the thickness direction of the sheet _45° And a cross section S cut in the direction of 90 DEG _90° Average crystal grain diameter A in the thickness direction of the sheet _90° All are 10.0 μm or less, and A _0° Standard deviation of (A) _45° Standard deviation of (A) and _90° has an average value of standard deviation of 2.0 μm or less,

the average crystal grain diameter A represented by the following formula (1) _0° Degree of anisotropy B of _0° And the average crystal grain diameter A _45° Degree of anisotropy B of _45° And the average crystal grain diameter A _90° Degree of anisotropy B of _90° All of them are 10.0% or less.

B _m ＝100×(A _m -C)/C … … formula (1)

Wherein in the formula (1), m is 0 °, 45 ° or 90 °, and C is A _0° 、A _45° And A _90° Average value of (A) ((A) _0° +A _45° +A _90° )/3)。

[2]As described above [1]The copper alloy sheet material, wherein the cross section S _0° Average crystal grain diameter D in the rolling direction of (1) _0° Is 15.0 μm or less.

[3]As described above [1]Or [2]]The copper alloy sheet is characterized in that the section S is _0° Average KAM value E in _0° The above section S _45° Average KAM value E in _45° And the section S _90° Average KAM value E in _90° All are 10.0 DEG or less, and E _0° Standard deviation of (E), E _45° Standard deviation of (1) and (E) _90° Has an average value of standard deviation of 3.0 DEG or less, and the average KAM value E represented by the following formula (2) _0° Degree of anisotropy F of _0° The average KAM value E _45° Degree of anisotropy F of _45° And the average KAM value E _90° Degree of anisotropy F of _90° All of them are 10.0% or less.

F _m ＝100×(E _m -G)/G … … formula (2)

Wherein in the formula (2), m is 0 °, 45 ° or 90 °, and G is E _0° 、E _45° And E _90° Average value of ((E) _0° +E _45° +E _90° )/3)。

[4] A copper alloy sheet material characterized by having the following alloy composition: contains 0.10 to 0.80 mass% of Cr, and the balance of Cu and unavoidable impurities,

a tensile strength of 350MPa to 800MPa, an electrical conductivity of 55% to 90% IACS,

a section S cut in the direction of 0 DEG with respect to the rolling direction _0° Average KAM value E in _0° A section S cut in the direction of 45 DEG _45° Average KAM value E in _45° And in the 90 DEG directionCut-out section S _90° Average KAM value E in _90° All are 10.0 DEG or less, and E _0° Standard deviation of (E), E _45° Standard deviation of (1) and (E) _90° Has an average value of standard deviation of 3.0 DEG or less, and the average KAM value E represented by the following formula (2) _0° Degree of anisotropy F of _0° The average KAM value E _45° Degree of anisotropy F of _45° And the average KAM value E _90° Degree of anisotropy F of _90° All of them are 10.0% or less.

F _m ＝100×(E _m -G)/G … … formula (2)

Wherein in the formula (2), m is 0 °, 45 ° or 90 °, and G is E _0° 、E _45° And E _90° Average value of ((E) _0° +E _45° +E _90° )/3)。

[5] The copper alloy sheet material according to any one of the above [1] to [4], wherein the alloy composition further contains 0.05 to 2.50 mass% in total of at least 1 element selected from the group consisting of Mg, Ti, Co, Zr, Zn, Sn and Si.

[6] The copper alloy sheet material according to any one of the above [1] to [5], wherein the thickness is 0.05mm or more and 0.50mm or less.

[7] A method for producing a copper alloy sheet material according to any one of the above [1] to [6],

a copper alloy material is subjected to a casting step (step 1), a homogenization heat treatment step (step 2), a hot rolling step (step 3), a surface cutting step (step 4), a cold rolling step (step 5), an intermediate heat treatment step (step 6), a cold finish rolling step (step 7), and a temper annealing step (step 8) in this order,

the ratio (T6/R5) of the highest temperature T6 (DEG C) of the heat-treated material in the intermediate heat treatment step (step 6) to the reduction ratio R5 (%) of the rolled material in the cold rolling step (step 5) is 8.0 to 20.0,

the maximum temperature T6 is 400 to 650 ℃,

the ratio (T8/M7) of the maximum temperature T8 (DEG C) of the annealed material in the thermal refining annealing step (step 8) to the average M7 of each pass of the roll gap shape ratio represented by the following formula (3) of the pair of work rolls provided in each pass of the cold finish rolling step (step 7) is 10.0 to 100.0,

the maximum temperature T8 is 250 to 700 ℃.

M7＝3×{r(h ₁ -h ₂ )} ^1/2 /{n(h ₁ +2h ₂ ) … … type (3)

Wherein in the formula (3), r is the radius (mm) of the working roll, h ₁ The thickness (mm), h) of the rolled material before each pass of the cold finish rolling step (step 7) ₂ N is the total number of passes of the cold finish rolling step (step 7), and is the thickness (mm) of the rolled material after each pass of the cold finish rolling step (step 7).

[8] A member for electric/electronic components, characterized in that the copper alloy sheet material according to any one of the above [1] to [6] has burring holes.

[9] The member for electric/electronic components according to [8], wherein the burring hole has a hole expansion rate λ of 20% or more, which is represented by the following formula (4).

λ＝100×(d―d ₀ )/d ₀ … … type (4)

Wherein, in the above formula (4), d ₀ The diameter (mm) of the hole before reaming is adopted, and the diameter (mm) of the flanging hole after reaming is adopted.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a copper alloy sheet material, a method for producing the same, and a member for electric and electronic components, which exhibit sufficient strength and conductivity and which are excellent in burring workability even when burring is performed under difficult working conditions.

Drawings

[ FIG. 1] A]FIG. 1 is a cross section S for a copper alloy sheet _0° Section S _45° And section S _90° The drawings to be described are shown.

Fig. 2 is a diagram for explaining an average value M7 of the roll gap shape ratio in the finish cold rolling step (step 7).

Fig. 3 is a schematic cross-sectional view showing an example of punching in the burring.

Fig. 4 is a schematic cross-sectional view showing an example of a hole enlargement in the burring.

Detailed Description

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

As a result of intensive studies, the inventors of the present application have found that excellent burring workability can be obtained without impairing the balance between strength and conductivity by controlling the crystal grain size of the copper alloy sheet material, the KAM value corresponding to the local strain amount, and the uniformity and anisotropy thereof with high accuracy, even when the burring is performed under difficult working conditions, and have completed the present invention based on the above findings.

The copper alloy sheet material of the embodiment has the following alloy composition: contains 0.10 to 0.80 mass% of Cr, and the balance of Cu and unavoidable impurities,

a tensile strength of 350MPa to 800MPa, an electrical conductivity of 55% to 90% IACS,

a section S cut in the direction of 0 DEG with respect to the rolling direction _0° Average crystal grain diameter A in the thickness direction of the sheet _0° A section S cut in the direction of 45 DEG _45° Average crystal grain diameter A in the thickness direction of the sheet _45° And a cross section S cut in the direction of 90 DEG _90° Average crystal grain diameter A in the thickness direction of the sheet _90° All are 10.0 μm or less, and A _0° Standard deviation of (A) _45° Standard deviation of (A) and _90° has an average value of standard deviation of 2.0 μm or less,

the average crystal grain diameter A represented by the following formula (1) _0° Degree of anisotropy B of _0° The average crystal grain diameter A _45° Degree of anisotropy B of _45° And the average crystal grain diameter A _90° Degree of anisotropy B of _90° All of them are 10.0% or less.

B _m ＝100×(A _m -C)/C … … formula (1)

In the above-mentioned formula (1),m is 0 degree, 45 degrees or 90 degrees, C is A _0° 、A _45° And A _90° Average value of ((A) _0° +A _45° +A _90° )/3)。

In addition, the copper alloy sheet material of the embodiment has the following alloy composition: contains 0.10 to 0.80 mass% of Cr, and the balance of Cu and unavoidable impurities,

a tensile strength of 350MPa to 800MPa, an electrical conductivity of 55% to 90% IACS,

a section S cut in the direction of 0 DEG with respect to the rolling direction _0° Average KAM value E in _0° A section S cut in the direction of 45 DEG _45° Average KAM value E in _45° And a cross section S cut in the direction of 90 DEG _90° Average KAM value E in _90° All are 10.0 DEG or less, and E _0° Standard deviation of (E), E _45° Standard deviation of (1) and (E) _90° Has an average value of standard deviation of 3.0 DEG or less,

the average KAM value E represented by the following formula (2) _0° Degree of anisotropy F of _0° The average KAM value E _45° Degree of anisotropy F of _45° And the average KAM value E _90° Degree of anisotropy F of _90° All of them are 10.0% or less.

F _m ＝100×(E _m -G)/G … … formula (2)

In the above formula (2), m is 0 °, 45 ° or 90 °, and G is E _0° 、E _45° And E _90° Average value of ((E) _0° +E _45° +E _90° )/3)。

First, the alloy composition of the copper alloy sheet material will be described.

The copper alloy sheet material of the above embodiment has the following alloy composition: contains 0.10 to 0.80 mass% of Cr, and the balance of Cu and unavoidable impurities.

< Cr: 0.10 to 0.80 mass%

Cr (chromium) is an element necessary for improving the strength of the copper alloy sheet material, and 0.10 mass% to 0.80 mass% of Cr is required. When the content of Cr is 0.10 mass% or more, the strength of the copper alloy sheet is increased, and the burring workability is improved. When the content of Cr is 0.80 mass% or less, coarse crystals including Cr are less likely to be generated in the casting step, and the burring workability is improved. Therefore, the lower limit of the content of Cr is 0.10 mass%, preferably 0.2 mass%, more preferably 0.3 mass%, and the upper limit of the content of Cr is 0.80 mass%, preferably 0.7 mass%, more preferably 0.6 mass%.

< subcomponent of copper alloy sheet: 0.05 to 2.50 mass%

The alloy composition of the copper alloy sheet material may further contain 0.05 to 2.50 mass% in total of 1 or more elements selected from the group consisting of Mg, Ti, Co, Zr, Zn, Sn, and Si. That is, the copper alloy sheet material may contain, as optional subcomponents, not less than 1 component selected from the group consisting of Mg, Ti, Co, Zr, Zn, Sn and Si in a total amount of 0.05 to 2.50 mass% in addition to Cr as an essential component. When the content of the subcomponent is 0.05 mass% or more, the strength of the copper alloy sheet can be improved, and the effect of slowing down recrystallization in the hot rolling step and recrystallization in the intermediate heat treatment step is exhibited, so that the crystal grain size, the KAM value, and the uniformity and anisotropy of the crystal grain size and the KAM value in a crystal state of the copper alloy sheet can be easily controlled within a predetermined range, and the burring workability can be improved. When the content of the subcomponent is 2.50% by mass or less, the decrease in the electrical conductivity of the copper alloy sheet material can be suppressed. Therefore, the lower limit of the content of the subcomponent is preferably 0.05 mass%, more preferably 0.30 mass%, and still more preferably 0.50 mass%, and the upper limit of the content of the subcomponent is preferably 2.50 mass%, more preferably 2.20 mass%, and still more preferably 1.90 mass%.

< Mg: 0.05-0.20 mass%

When the Mg (magnesium) content is 0.05 mass% or more, the effect of solid solution strengthening the copper alloy sheet is exhibited. When the Mg content is 0.20 mass% or less, the decrease in the electrical conductivity of the copper alloy sheet material can be suppressed. Therefore, the lower limit of the Mg content is preferably 0.05 mass%, and the upper limit of the Mg content is preferably 0.20 mass%.

< Ti: 0.05 to 0.20 mass%

When the content of Ti (titanium) is 0.05 mass% or more, the Ti (titanium) is dissolved in the copper alloy sheet and the recrystallization temperature of the copper alloy sheet is increased, thereby exerting an effect of suppressing the coarsening of dynamic recrystallization grains in the hot rolling step. When the content of Ti is 0.20 mass% or less, the decrease in the electrical conductivity of the copper alloy sheet material can be suppressed to a level at which the necessary heat dissipation properties of the shield case and the like can be ensured to the minimum. Therefore, the lower limit of the Ti content is preferably 0.05 mass%, and the upper limit of the Ti content is preferably 0.20 mass%.

< Co: 0.05 to 1.50 mass%

When the content of Co (cobalt) is 0.05 mass% or more, the strength of the copper alloy sheet increases. When the content of Co exceeds 1.50 mass%, the electrical conductivity of the copper alloy sheet decreases, and this leads to an increase in the cost of the raw material metal. Therefore, the lower limit of the content of Co is preferably 0.05 mass%, and the upper limit of the content of Co is preferably 1.50 mass%.

< Zr: 0.05 to 0.20 mass%

When the content of Zr (zirconium) is 0.05 mass% or more, coarsening of dynamic recrystallization grains during hot rolling is suppressed, which contributes to improvement of the strength of the copper alloy sheet. When the Zr content exceeds 0.20 mass%, coarse crystals are generated during the casting process, and may become starting points of fracture during the flanging process. Therefore, the lower limit of the Zr content is preferably 0.05 mass%, and the upper limit of the Zr content is preferably 0.20 mass%.

< Zn: 0.05 to 0.60 mass%

When the content of Zn (zinc) is 0.05 mass% or more, the adhesion and migration characteristics of the Sn plating layer and the solder plating layer can be improved. When the Zn content is 0.60 mass% or less, the decrease in the electrical conductivity of the copper alloy sheet material can be suppressed, and sufficient heat dissipation can be obtained. Therefore, the lower limit of the Zn content is preferably 0.05 mass%, and the upper limit of the Zn content is preferably 0.60 mass%.

< Sn: 0.05-0.30 mass%

When the Sn (tin) content is 0.05 mass% or more, the effect of solid solution strengthening the copper alloy sheet is exhibited. When the Sn content is 0.30 mass% or less, the decrease in the electrical conductivity of the copper alloy sheet material can be suppressed. Therefore, the lower limit of the Sn content is preferably 0.05 mass%, and the upper limit of the Sn content is preferably 0.30 mass%.

< Si: 0.02 to 0.40 mass%

When the content of Si (silicon) is 0.02 mass% or more, Si compounds are formed with other additive elements such as Co, Mg, and Cr, and the strength of the copper alloy sheet material increases. When the content of Si is 0.40 mass% or less, a decrease in thermal conductivity of the copper alloy sheet material can be suppressed, and sufficient heat dissipation can be obtained. Therefore, the lower limit of the Si content is preferably 0.02 mass%, and the upper limit of the Si content is preferably 0.40 mass%.

< allowance: cu and inevitable impurities

The balance other than the above components is Cu (copper) and inevitable impurities. The inevitable impurities are the following impurity components: the impurity component is an impurity component which is inevitably mixed in the production process, is not necessary per se, but is a trace amount, and does not affect the characteristics of the copper alloy sheet material, and is therefore allowable. The smaller the content of inevitable impurities, the more preferable. Examples of the inevitable impurities include Bi (bismuth), Se (selenium), As (arsenic), Ag (silver), and the like. The upper limit of the content of these components is preferably 0.03 mass% in terms of the above components, and is preferably 0.10 mass% in terms of the total amount of the above components.

Next, the tensile strength of the copper alloy sheet material will be described.

The tensile strength of the copper alloy sheet is 350MPa to 800 MPa. When the tensile strength of the copper alloy sheet material is 350MPa or more, the strength is improved, and therefore, the protection of electric and electronic equipment such as a shield case, a camera module, and a battery pack case, which are provided with the copper alloy sheet material, can be achieved at the same time, and the heat dissipation performance is improved. Further, when the tensile strength of the copper alloy sheet material is 800MPa or less, the heat dissipation property and the workability of the copper alloy sheet material can be suppressed from being lowered. Therefore, the lower limit of the tensile strength is 350MPa, preferably 370MPa, more preferably 400MPa, and the upper limit of the tensile strength is 800MPa, preferably 750MPa, more preferably 700 MPa.

The tensile strength of the copper alloy sheet material can be determined by: using JIS 13B test pieces, based on JIS Z2241: 2011, a tensile test is performed. The tensile strength of the copper alloy sheet is the tensile strength in the direction parallel to the rolling.

Next, the electrical conductivity of the copper alloy sheet material will be described.

The electrical conductivity of the copper alloy sheet is 55% IACS to 90% IACS. It is known that the thermal conductivity can be calculated from the electrical conductivity according to the Willeman-Franz law (Wiedemann-Franz law), and is proportional to the electrical conductivity regardless of the kind of metal if the temperature is constant. Therefore, when the electrical conductivity of the copper alloy plate material is 55% IACS or more, high thermal conductivity can be achieved, and as a result, the electrical and electronic devices such as a shield case, a camera module, and a battery pack case, which are provided with the copper alloy plate material, have excellent heat dissipation properties. When the electrical conductivity of the copper alloy sheet material is 90% IACS or less, the strength of the copper alloy sheet material required as a member for electric and electronic components mounted on these electric and electronic devices can be secured to the minimum. Therefore, the lower limit of the electrical conductivity is 55% IACS, preferably 60% IACS, and the upper limit of the electrical conductivity is 90% IACS. Thus, the higher the electrical conductivity of the copper alloy sheet material, the more preferable.

The electrical conductivity of the copper alloy sheet can be calculated as follows: the resistivity was measured by a 4-terminal method in a constant temperature bath maintained at 20 ℃ (± 0.5 ℃) with an inter-terminal distance of 100 mm.

Next, the average crystal grain size a and the degree of anisotropy B of the copper alloy sheet material will be described.

As shown in fig. 1, regarding the copper alloy sheet material 10, a cross section S cut in a direction of 0 ° with respect to the rolling direction _0° Average crystal grain diameter A in the thickness direction of the sheet _0° Is 10.0 μm or less. In addition, a section S cut in a direction of 45 ° with respect to the rolling direction _45° Average crystal grain diameter A in the thickness direction of the sheet _45° Is 10.0 μm or less. In addition, a section S cut in a direction of 90 ° with respect to the rolling direction _90° Average crystal grain diameter A in the thickness direction of the sheet _90° Is 10.0 μm or less. Average crystal grain diameter A _0° Average crystal grain diameter A _45° Or average crystal grain diameter A _90° If the thickness exceeds 10.0 μm, the interface between the sheared surface and the torn surface in the fracture surface of the through-hole formed by press punching becomes uneven, and cracks are caused during hole expansion. From the viewpoint of improving the burring workability, the average crystal grain diameter A _0° Average crystal grain diameter A _45° And average crystal grain diameter A _90° All of them are 10.0 μm or less, preferably 8.0 μm or less, and more preferably 5.0 μm or less. As described above, the smaller the average crystal grain size is, the more preferable the average crystal grain size is.

Further, the average crystal grain diameter A _0° Standard deviation of (A), average crystal grain diameter (A) _45° Standard deviation of (A) and average crystal grain diameter A _90° The average value of the standard deviation of (A) is 2.0 μm or less. When the average value calculated by averaging the standard deviations of the average crystal grain sizes is larger than 2.0 μm, the variation in crystal grain sizes becomes large, the interface between the shear plane and the tear plane in the fracture plane of the through hole formed by press punching becomes uneven, and cracks are caused during hole expansion. From the viewpoint of improving the burring workability, the average value of the standard deviation of the average crystal grain size is 2.0 μm or less, preferably 1.8 μm or less, and more preferably 1.0 μm or less. As described above, the smaller the average value of the standard deviation is, the more preferable.

Further, the average crystal grain diameter A represented by the above formula (1) _0° Degree of anisotropy B of _0° Is 10.0% or less. Average crystal grain diameter A represented by the above formula (1) _45° Degree of anisotropy B of _45° Is 10.0% or less. Average crystal grain diameter A represented by the above formula (1) _90° Degree of anisotropy B of _90° Is 10.0% or less. If degree of anisotropy B _0° Degree of anisotropy B _45° Or degree of anisotropy B _90° If the ratio is more than 10.0%, the interface between the sheared surface and the torn surface becomes uneven in the fracture surface of the through-hole formed by press punching, and cracks are caused during hole expansion. From the improvement of the turnup workabilityFrom the viewpoint of anisotropy B _0° Degree of anisotropy B _45° And degree of anisotropy B _90° All of them are 10.0% or less, preferably 8.0% or less, and more preferably 5.0% or less. As described above, the smaller the degree of anisotropy, the more preferable.

Further, as shown in fig. 1, the copper alloy sheet material 10 has a cross section S cut in a direction of 0 ° with respect to the rolling direction _0° Average crystal grain diameter D in the rolling direction of (1) _0° Preferably 15.0 μm or less, more preferably 13.0 μm or less. If the average crystal grain diameter D _0° If the diameter is larger than 15.0 μm, deep wrinkles in the rolling direction are likely to occur in the root (bent portion) of the hole flange formed after the hole expansion process, and cracks are likely to occur. Thus, the above-mentioned average crystal grain diameter D _0° Smaller is more preferable.

The crystal grain size can be obtained from crystal orientation Analysis data obtained by continuously measuring the crystal orientation data with an EBSD detector attached to a high-resolution scanning electron microscope (JSM-7001 FA, manufactured by japan electronics corporation) and calculating the crystal grain size with Analysis software (OIM Analysis, manufactured by TSL corporation). "EBSD" is an abbreviation for Electron back scattering Diffraction (Electron back scattering Diffraction), and is a crystal orientation analysis technique using the Diffraction of reflected Electron beam generated when a copper alloy plate material as a sample is irradiated with an Electron beam in a Scanning Electron Microscope (SEM). "OIM Analysis" refers to the Analysis software for the data measured by EBSD. The measurement area is a section S cut by electropolishing in the direction of 0 DEG with respect to the rolling direction as shown in FIG. 1 _0° A section S cut in a direction of 45 DEG with respect to the rolling direction _45° A section S cut in a direction of 90 DEG with respect to the rolling direction _90° And mirror finishing the resulting surface. The measurement was performed in a step size of 0.1 μm in a visual field of total thickness × width 150. mu.m. The grain boundaries are grain boundaries having a difference in orientation of 15 ° or more, and grains containing 2 or more pixels (pixels) are analyzed.

Then, in the obtained IPF image (Inverse Pole Figure), 50 μm intervals were observed2 lines parallel to the direction of the plate thickness and intersecting the plate thickness were drawn at intervals, the crystal grain size was measured by the cutting method and averaged, and the obtained results were each taken as the average crystal grain size A _0° Average crystal grain diameter A _45° Average crystal grain diameter A _90° . In the obtained IPF image, 2 perpendicular lines having a length of 150 μm were drawn at intervals of 25 μm in the thickness direction, the crystal grain diameters were measured by a cutting method and averaged, and the obtained result was defined as an average crystal grain diameter D _0° . The standard deviation of each average crystal grain size was calculated for each crystal grain on each line.

Next, the average KAM value E and the degree of anisotropy F of the copper alloy sheet material will be described.

As shown in fig. 1, regarding the copper alloy sheet material 10, a cross section S cut in a direction of 0 ° with respect to the rolling direction _0° Average KAM value E in _0° Is 10.0 DEG or less. In addition, a section S cut in a direction of 45 ° with respect to the rolling direction _45° Average KAM value E in _45° Is 10.0 DEG or less. In addition, a section S cut in a direction of 90 ° with respect to the rolling direction _90° Average KAM value E in _90° Is 10.0 DEG or less. Average KAM value E _0° Average KAM value E _45° Or average KAM value E _90° If the angle is more than 10.0 °, a large amount of strain is accumulated in the copper alloy sheet material, and the burring workability is deteriorated. From the viewpoint of improving the burring workability, the average KAM value E _0° Average KAM value E _45° And average KAM value E _90° All of them are 10.0 ° or less, preferably 7.0 ° or less, and more preferably 3.0 ° or less. In addition, from the viewpoint of material strength, the average KAM value E _0° Average KAM value E _45° And average KAM value E _90° Are preferably 1.0 ° or more.

In addition, the average KAM value E _0° Standard deviation, mean KAM value E of _45° Standard deviation and mean KAM value E of _90° The average value of the standard deviation of (a) is 3.0 ° or less. When the average value calculated by averaging the standard deviations of these average KAM values is larger than 3.0 °, strain distribution becomes uneven, and deformation tends to concentrate locally during hole expanding, and therefore deformation tends to occur locallyCracks are initiated. From the viewpoint of improving the burring workability, the average value of the standard deviation of the average KAM value is 3.0 ° or less, preferably 1.0 ° or less, and more preferably 0.5 ° or less. As described above, the smaller the average value of the standard deviation is, the more preferable.

Further, the average KAM value E represented by the above formula (2) _0° Degree of anisotropy F of _0° Is 10.0% or less. Average KAM value E represented by the above formula (2) _45° Degree of anisotropy F of _45° Is 10.0% or less. Average KAM value E represented by the above formula (2) _90° Degree of anisotropy F of _90° Is 10.0% or less. Degree of anisotropy F _0° Degree of anisotropy F _45° Or degree of anisotropy F _90° If the amount is more than 10.0%, the circumferential anisotropy of strain distribution is large, and cracks are caused when the hole is bored into a circular shape. From the viewpoint of improving the burring workability, the degree of anisotropy F _0° Degree of anisotropy F _45° And degree of anisotropy F _90° All of them are 10.0% or less, preferably 5.0% or less.

The value of KAM (Kernel Average degree of mismatch) is an Average value of differences in crystal orientation between a measurement point and all measurement points adjacent thereto. The KAM value is related to the dislocation density and corresponds to the amount of lattice strain in the crystal.

The KAM value can be obtained from crystal orientation Analysis data calculated by using Analysis software (OIM Analysis, manufactured by TSL Co., Ltd.) from crystal orientation data continuously measured by using an EBSD detector attached to a high-resolution scanning type Analysis electron microscope (JSM-7001 FA, manufactured by JSM-K.K.). The measurement area is a section S cut by electropolishing in the direction of 0 DEG with respect to the rolling direction as shown in FIG. 1 _0° A section S cut in a direction of 45 DEG with respect to the rolling direction _45° A section S cut in a direction of 90 DEG with respect to the rolling direction _90° And mirror finishing the resulting surface. The measurement was performed in a 0.1 μm step size in a visual field of total thickness × width 150. mu.m. The grain boundary is 15 deg. or more of orientation difference, and 2 pixels are includedThe upper crystal grain is the object of analysis.

Then, in the obtained KAM image, 2 lines parallel to the plate thickness direction and intersecting the plate thickness were drawn at intervals of 50 μm, the KAM values in the crystal grains on the respective lines were measured and averaged, and the obtained results were respectively regarded as an average KAM value E _0° Average KAM value E _45° Average KAM value E _90° . The standard deviation of each average KAM value was calculated for each crystal grain on each line.

The copper alloy sheet material in which the average crystal grain size a and the anisotropy degree B are controlled within the predetermined ranges as described above has good burring workability. In addition, the copper alloy sheet material in which the average KAM value E and the anisotropy F thereof are controlled within the predetermined ranges respectively has good burring workability. Furthermore, the method is simple. The copper alloy sheet material, in which the average crystal grain diameter A and the degree of anisotropy B are controlled within the predetermined ranges, and the average KAM value E and the degree of anisotropy F are controlled within the predetermined ranges, has further improved burring workability.

Further, the upper limit value of the thickness of the copper alloy sheet material is preferably 0.50mm, and the lower limit value thereof is preferably 0.05 mm. When the thickness of the copper alloy sheet material is greater than 0.50mm, deep wrinkles are likely to form on the outer side and the inner side of the root of the hole flange formed after the burring, and cracks may occur and progress. When the thickness of the copper alloy sheet material is less than 0.05mm, the rigidity of the copper alloy sheet material is lowered.

Next, a method for manufacturing the copper alloy sheet material according to the embodiment will be described. In the method for producing a copper alloy sheet according to the embodiment, a casting step (step 1), a homogenization heat treatment step (step 2), a hot rolling step (step 3), a surface cutting step (step 4), a cold rolling step (step 5), an intermediate heat treatment step (step 6), a cold finish rolling step (step 7), and a temper annealing step (step 8) are sequentially performed on a copper alloy material, a ratio (T6/R5) of a maximum temperature T6(° c) of the heat-treated material in the intermediate heat treatment step (step 6) to a reduction ratio R5 (%) of the rolled material in the cold rolling step (step 5) is 8.0 to 20.0, the maximum temperature T6 is 400 ℃ to 650 ℃, and a pass T8(° c) of the annealed material in the temper annealing step (step 8) to a maximum temperature of a pair of work rolls provided in each of the cold finish rolling steps (step 7) is 8), The ratio (T8/M7) of the average M7 in each pass of the roll gap shape ratio represented by the following formula (3) is 10.0 to 100.0, and the maximum temperature T8 is 250 ℃ to 700 ℃.

M7＝3×{r(h ₁ -h ₂ )} ^1/2 /{n(h ₁ +2h ₂ ) … … type (3)

In the above formula (3), r is the radius (mm) of the work roll, h ₁ The thickness (mm), h) of the rolled material before each pass of the cold finish rolling step (step 7) ₂ N is the total number of passes of the cold finish rolling step (step 7), and is the thickness (mm) of the rolled material after each pass of the cold finish rolling step (step 7).

In the casting step [ step 1], the alloy components are melted and cast to obtain a copper alloy ingot having a predetermined shape. For example, the melting is performed under the atmosphere using a high-frequency melting furnace. The kind of alloy components, casting conditions, and the like are appropriately set.

In the homogenization heat treatment step (step 2), the copper alloy ingot obtained in the casting step (step 1) is subjected to homogenization heat treatment under predetermined heating conditions (for example, at 1000 ℃ or lower for 1 hour). The homogenization heat treatment step (step 2) is performed, for example, in the air.

In the hot rolling step (step 3), the steel sheet is cooled immediately after reaching a predetermined thickness (for example, 15 mm).

In the surface cutting step (step 4), surface cutting is performed from the surface of the hot-rolled sheet to a predetermined thickness (for example, 2.5mm to 5.0 mm) to remove the oxide film.

In the cold rolling step (step 5), cold rolling is performed so that the reduction ratio R5 of the rolled material is 25% to 70%.

In the intermediate heat treatment step (step 6), the heat treatment is performed under conditions in which the maximum temperature T6 of the heat-treated material is 400 to 650 ℃ inclusive and the holding time at the maximum temperature T6 is 1 minute to 10 hours inclusive. The intermediate heat treatment step (step 6) is performed in a non-oxidizing atmosphere such as argon. The lower limit of the maximum temperature T6 of the heat-treated material in the intermediate heat treatment step (step 6) is 400 ℃. When the maximum temperature T6 of the heat-treated material in the intermediate heat treatment step (step 6) is 400 ℃ or higher, the recovery of the heat-treated material improves the burring workability, and Cr particles precipitate, resulting in an increase in strength and electrical conductivity. On the other hand, above a maximum temperature T6 of 650 ℃, softening of the material proceeds.

The ratio (T6/R5) of the highest temperature T6 (DEG C) of the heat-treated material in the intermediate heat treatment step (step 6) to the reduction ratio R5 (%) of the rolled material in the cold rolling step (step 5) is 8.0 to 20.0. When the ratio (T6/R5) is within the above range, the strength and conductivity can be exhibited with good balance.

As the reduction ratio R5 is higher, the driving force for generating the Cr-containing compound as the 2 nd phase in the copper alloy sheet material is reduced, and the maximum temperature T6 in the intermediate heat treatment step (step 6) in which the increase in strength of the copper alloy sheet material due to the generation of the 2 nd phase reaches a peak is lowered. Further, the generation of the 2 nd phase is promoted and the conductivity of the copper alloy sheet material is improved as the maximum temperature T6 in the intermediate heat treatment step (step 6) is higher. On the other hand, if the maximum temperature T6 is too high, the crystal grains become coarse after recrystallization, and the burring workability is reduced. Therefore, the balance between the machining rate R5 and the maximum temperature T6 is important, and the control of the maximum temperature T6 itself is also important.

In the cold finish rolling step (step 7), cold rolling is performed by a pair of work rolls provided in each pass. The maximum temperature of the rolled material in the finish cold rolling is, for example, 75 ℃ to 150 ℃. The finish cold rolling step (step 7) is performed to obtain a copper alloy sheet having a predetermined thickness, to improve the strength of the copper alloy sheet, and to control the crystal state such as the crystal grain size and the KAM value.

The average value M7 of each pass of the roll gap shape ratio represented by the formula (3) in the finish cold rolling step (step 7) will be described with reference to fig. 2.

M7＝3×{r(h ₁ -h ₂ )} ^1/2 /{n(h ₁ +2h ₂ ) … … type (3)

As shown in fig. 2, in the finish cold rolling step (step 7), a pair of work rolls 20 is provided for each pass. Along which a pair of work rolls 20 having a radius r lieThis opposite direction rotates. The rolled material has a thickness h when moving in the rolling direction ₁ The rolled material 21 before each pass is cooled and rolled by the rotation of the work rolls 20, and is processed to have a thickness h ₂ The rolled material 22 after each pass.

In the thermal refining annealing step (step 8), the annealing material is heat-treated under conditions in which the maximum temperature T8 of the annealing material is 250 ℃ to 700 ℃ inclusive and the holding time at the maximum temperature T8 is 10 seconds to 1 hour inclusive. The thermal refining annealing step (step 8) under such heat treatment conditions is performed to recover the elongation of the copper alloy sheet material and reduce the anisotropy of mechanical properties including the elongation. The thermal annealing step (step 8) is performed in a non-oxidizing atmosphere such as argon.

The lower limit of the ratio (T8/M7) of the maximum temperature T8 (c) of the annealed material in the heat treatment annealing step (step 8) to the average value M7 of the roll gap shape ratio in each pass in the cold finish rolling step (step 7) was 10.0, and the upper limit was 100.0. When the ratio (T8/M7) is within the above range, the KAM value and anisotropy of the KAM value are controlled, and the burring workability is improved. Further, by controlling the ratio (T6/R5) and the ratio (T8/M7), the crystal grain size, the anisotropy thereof, and the standard deviation thereof can be controlled.

Generally, in a rolled material, the deformed structure is different because the internal metal flow (forging flow line) differs between the vicinity of the surface layer at a short distance from the work rolls and the internal metal flow at a long distance. The crystal grain size and the KAM value after the heat treatment in the thermal refining and annealing step (step 8), and the anisotropy and standard deviation thereof can be controlled by appropriately adjusting the average value M7 of the roll gap shape ratio.

When the roll gap shape ratio in the cold finish rolling step (step 7) is larger than the average value M7, that is, when the reduction per 1 pass is large or the radius of the work roll is large, a uniform deformed structure is easily formed throughout from the surface layer to the inside of the rolled material, and the copper alloy sheet material that has been subjected to strain relief in the temper annealing step (step 8) is easily formed into a uniform structure. Therefore, the holding time at the maximum temperature T8 and the maximum temperature T8 in the thermal refining and annealing step (step 8) is determined by the balance between the strain removal and the softening. For example, a ratio (T8/M7) of greater than 100.0 results in internal softening of the unstrained copper alloy sheet material.

In the method for producing a copper alloy sheet material according to the above embodiment, it is preferable that a cold rolling step (step a1) and an intermediate heat treatment step (step a2) are further provided between the surface cutting step (step 4) and the cold rolling step (step 5). Specifically, the cold rolling step (step a1) is performed after the surface cutting step (step 4), the intermediate heat treatment step (step a2) is performed after the cold rolling step (step a1), and the cold rolling step (step 5) is performed after the intermediate heat treatment step (step a 2).

The intermediate heat treatment step (step a2) is a step performed to easily adjust the reduction ratio of the rolled material in the cold rolling step (step 5), and is performed, for example, under conditions in which the maximum temperature of the heat-treated material is 300 ℃ to 1000 ℃ inclusive and the holding time at the maximum temperature is 10 seconds to 3 hours inclusive. In the cold rolling step (step a1), the reduction ratio of the rolled material is appropriately adjusted so that the rolled material has a predetermined reduction ratio in the cold rolling step (step 5). When the intermediate heat treatment step (step a2) is not performed, the cold rolling step (step a1) may be performed in the cold rolling step (step 5). Depending on the thickness of the copper alloy sheet to be produced and the thickness of the sheet to be produced, the cold rolling step (step a1) and the intermediate heat treatment step (step a2) may be omitted.

Next, the electric/electronic component member according to the embodiment will be described. The electric/electronic component member according to the embodiment is a member having a burring hole in the copper alloy sheet material according to the above embodiment.

The burring hole formed by the burring will be described with reference to fig. 3 to 4.

First, as shown in fig. 3, a punching process of punching the copper alloy plate material 32 by the punching punch 31 is performed in the punching direction, thereby forming a diameter d in the copper alloy plate material 32 ₀ The through hole 33. Next, as shown in fig. 4, the hole-enlarging punch 34 is inserted into the through hole 33 in the insertion direction, and hole-enlarging processing is performed to plastically deform the periphery of the through hole 33 so as to enlarge the through hole 33, whereby insertion into the hole-enlarging punch 34 can be performedA convex burring hole 35 having a diameter d and protruding in the direction of insertion. In this way, the electrical/electronic component member 30 in which the burring hole 35 is formed in the copper alloy plate material 32 can be obtained.

Here, an example of the burring process in which the punching process and the hole expanding process are performed is shown, but the burring process is not particularly limited as long as a burring hole can be formed. For example, the burring may be performed by only enlarging a hole in a copper alloy sheet material having a through hole formed therein, without performing the punching.

The hole expansion ratio λ represented by the following formula (4) of the burring hole is preferably 20% or more. When the hole expansion ratio λ is 20% or more, the shape can be sufficiently designed when the member for electric and electronic components is used as a component of an electric and electronic device or the like.

λ＝100×(d―d ₀ )/d ₀ … … type (4)

In the above formula (4), d ₀ The diameter (mm) of the hole before reaming is adopted, and the diameter (mm) of the flanging hole after reaming is adopted. I.e. d ₀ D is the diameter of a burring hole formed by enlarging the through hole by a hole-enlarging process.

The member for electric and electronic components can be suitably used for electric and electronic devices such as connectors for electronic devices, lead frames, relays, switches, chassis, shield cases, liquid crystal reinforcing plates, chassis for liquid crystals, reinforcing plates for organic EL displays, camera modules, battery pack cases, connectors for automobile mounting, shield cases, and shield cases, which require excellent strength, conductivity, and high burring workability.

According to the embodiments described above, a copper alloy sheet material having predetermined tensile strength and electrical conductivity and having a crystal grain size, a KAM value, a standard deviation thereof, and a degree of anisotropy controlled within predetermined ranges can be produced. The copper alloy sheet material obtained in the above manner is superior in strength, conductivity, and burring workability to the conventional copper alloy sheet material in which the crystal grain size, KAM value, standard deviation thereof, and anisotropy degree are not controlled. Therefore, the member for electric and electronic components, which is formed by forming the burring hole in the copper alloy plate material, can be used for various electric and electronic devices that require balance of strength and electric conductivity and high burring property.

The embodiments have been described above, but the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention, including all embodiments included in the concept of the present invention and claims.

Examples

Next, examples and comparative examples will be described, but the present invention is not limited to these examples.

(examples 1 to 17 and comparative examples 1 to 11)

The respective alloy components were melted in a high-frequency melting furnace under the atmospheric air, and the molten alloy was cast with a mold to obtain copper alloy ingots having alloy compositions shown in Table 1 and a thickness of 30 mm. Next, the steel sheet was subjected to homogenization heat treatment at 1000 ℃ for 1 hour in the air, immediately hot-rolled to a thickness of 15mm, and then cooled with water. Then, the surface of the rolled sheet is subjected to surface cutting of 2.5mm to 5.0mm, thereby removing the oxide film to a thickness of 5.0mm to 10.0 mm. Then, cold rolling is performed so that the thickness becomes 1.25mm to 2.50mm, and then, intermediate heat treatment is performed at 300 ℃ to 1000 ℃ for 10 seconds. Next, as shown in table 2, cold rolling was performed at a reduction rate R5 and a thickness of 0.25mm to 1.25mm (step 5), intermediate heat treatment was performed in an argon atmosphere for a holding time of 1 minute to 360 minutes at the maximum temperature T6 and the maximum temperature T6 (step 6), cold finish rolling was performed for an average value M7 of each pass of the roll gap shape ratio (step 7), and temper annealing was performed in an argon atmosphere for a holding time of 1 minute to 60 minutes at the maximum temperature T8 and the maximum temperature T8 (step 8). Thus, a copper alloy sheet having a thickness shown in table 2 was obtained. In the copper alloy sheet materials shown in table 1, Bi, Se, As, and Ag are included As inevitable impurities, and the content of the inevitable impurities is 0.03 mass% or less in terms of the components and 0.10 mass% or less in terms of the total amount of the components.

[ Table 1]

[ Table 2]

[ measurement and evaluation ]

The following measurements and evaluations were made with respect to the copper alloy sheet materials obtained in the above examples and comparative examples. The results are shown in tables 3 to 5.

[1] Crystal grain size and KAM value

The crystal grain size and the KAM value were obtained from crystal orientation Analysis data obtained by continuously measuring the copper alloy sheet materials obtained in the above examples and comparative examples by using an EBSD detector attached to a high-resolution scanning electron microscope (JSM-7001 FA, manufactured by japan electronics corporation), and calculating the crystal orientation data from the obtained crystal orientation data by using Analysis software (OIM Analysis, manufactured by TSL corporation).

The measurement area is a section S cut by electropolishing in the direction of 0 DEG with respect to the rolling direction as shown in FIG. 1 _0° A section S cut in a direction of 45 DEG with respect to the rolling direction _45° A section S cut in a direction of 90 DEG with respect to the rolling direction _90° And mirror-finished surface. The measurement was performed in a 0.1 μm step size in a visual field of total thickness × width 150. mu.m. Further, the grain boundaries are set to be a difference in orientation of 15 ° or more, and grains including 2 pixels or more are analyzed.

Regarding the crystal grain size, 2 lines parallel to the sheet thickness direction and intersecting the sheet thickness were drawn at 50 μm intervals in the obtained IPF image, and the average crystal grain size a was calculated by measuring the crystal grain size by the cutting method and averaging _0° Average crystal grain size A _45° Average crystal grain diameter A _90° . In the obtained IPF image, 2 lines of 150 μm in length were drawn at intervals of 25 μm in the thickness directionThe perpendicular line of m is measured by a cutting method and averaged to calculate the average crystal grain diameter D _0° . The standard deviation of each average crystal grain size was calculated for each crystal grain on each line. Then, the average of the standard deviations of these average crystal grain sizes was calculated.

Regarding the KAM value, 2 lines parallel to the plate thickness direction and intersecting the plate thickness were drawn at 50 μm intervals in the obtained KAM image, and the KAM values in the crystal grains on the respective lines were measured and averaged to calculate an average KAM value E _0° Average KAM value E _45° Average KAM value E _90° . The standard deviation of each average KAM value was calculated for each crystal grain on each line. Then, the average of the standard deviations of these average KAM values is calculated.

[2] Tensile Strength (TS)

With respect to the copper alloy sheet materials obtained in the above examples and comparative examples, 3 (n is 3) test pieces of JIS 13B were used, and the sheet materials were prepared in accordance with JIS Z2241: 2011, a tensile test is performed, and the Tensile Strength (TS) is calculated by averaging 3 measurement values. The tensile strength is the tensile strength in the direction parallel to rolling.

[3] Conductivity (EC)

The copper alloy sheet materials obtained in the above examples and comparative examples were measured for resistivity by the 4-terminal method in a constant temperature bath maintained at 20 ℃ (± 0.5 ℃) with an inter-terminal distance of 100mm, thereby calculating the Electrical Conductivity (EC).

[4] Workability of turned-over edge

The copper alloy sheet materials obtained in the above examples and comparative examples were punched out by pressing with a clearance of 1/2 thickness of the copper alloy sheet material to have a diameter d ₀ A circular through hole of 10mm, and a punch having a tip angle of 60 ° and a diameter of 10 to 20mm is used to perform hole-expanding processing for expanding the through hole. Then, the hole expansion ratio at the time of fracture was taken as the hole expansion ratio λ. Further, the burring workability was classified as follows. The higher the hole expansion ratio λ, the better the burring workability.

Very good: lambda is more than 50%

O: the lambda is more than 20% and less than 50%

X: lambda is less than 20%

[ Table 3]

[ Table 4]

[ Table 5]

As shown in tables 1 to 5, in examples 1 to 17, the Cr content, the tensile strength, the electrical conductivity, the crystal grain size, the KAM value, and the anisotropy degree were controlled within predetermined ranges, and therefore, the strength, the electrical conductivity, and the burring workability were all good. In particular, in examples 1 and 8, the crystal grain size, KAM value, and anisotropy were further improved by adjusting the reduction ratio R5, the maximum temperature T6, the average value M7 of the roll gap shape ratio, the maximum temperature T8, the ratio (T6/R5), and the ratio (T8/M7) to the preferred ranges, respectively, and thus the burring workability was further improved.

On the other hand, in comparative example 1, the Cr content was small, the degree of anisotropy of the average KAM value was large, the maximum temperature T6 was low, the ratio (T6/R5) was large, the tensile strength was small, and the burring workability was poor. In comparative example 2, the maximum temperature T6 was low, and the tensile strength was low. In comparative example 3, the average crystal grain size, the degree of anisotropy thereof, and the average value of the standard deviation were large, the maximum temperature T6 was high, the tensile strength was small, and the burring workability was poor. In comparative example 4, since the content of Cr is high, coarse crystals including Cr are generated during casting and breakage is caused, and therefore, the burring workability is poor. In comparative example 5, the degree of anisotropy of the average KAM value was large, the electric conductivity was low, and the burring workability was poor. In comparative example 6, the average KAM value and the degree of anisotropy thereof were large, the maximum temperature T6 was low, the maximum temperature T8 was low, the ratio (T6/R5) was small, and the burring workability was poor. In comparative example 7, the average grain size and the average value of the standard deviation thereof were large, the maximum temperature T8 was high, the ratio (T8/M7) was large, the tensile strength was small, and the burring workability was poor. In comparative example 8, the tensile strength was small, as compared with (T6/R5). In comparative example 9, the tensile strength was higher than that of (T8/M7). In comparative example 10, the degree of anisotropy of the average KAM value was large, the ratio was large (T6/R5), the tensile strength was small, and the burring workability was poor. In comparative example 11, the average value of the degree of anisotropy and the standard deviation of the average crystal grain size was large, the degree of anisotropy of the average KAM value was large, it was larger than (T6/R5) and smaller than (T8/M7), and the burring workability was poor.

Description of the reference numerals

10 copper alloy sheet material

20 work roll

Rolled stock before 21 passes

Rolled stock after 22 passes

30 electric/electronic component member

31 punch for punching

32 copper alloy plate

33 through hole

34 punch for reaming holes

35 flanging processing hole

Claims (9)

1. A copper alloy sheet material characterized by having the following alloy composition: contains 0.10 to 0.80 mass% of Cr, and the balance of Cu and unavoidable impurities,

a tensile strength of 350MPa to 800MPa,

the electrical conductivity is more than 55% IACS and less than 90% IACS,

a section S cut in the direction of 0 DEG with respect to the rolling direction _0° Average crystal grain diameter A in the thickness direction of the sheet _0° A section S cut in the direction of 45 DEG _45° Average crystal grain diameter A in the thickness direction of the sheet _45° And a cross section S cut in the direction of 90 DEG _90° Average crystal grain diameter A in the thickness direction of the sheet _90° All are 10.0 μm or less, and A _0° Standard deviation of (A) _45° Standard deviation of (A) and _90° has an average value of standard deviation of 2.0 μm or less,

the average crystal grain diameter A represented by the following formula (1) _0° Degree of anisotropy B of _0° The average crystal grain diameter A _45° Degree of anisotropy B of _45° And the average crystal grain diameter A _90° Degree of anisotropy B of _90° All the components are below 10.0 percent,

B _m ＝100×(A _m -C)/C … … formula (1)

Wherein in the formula (1), m is 0 degrees, 45 degrees or 90 degrees, and C is A _0° 、A _45° And A _90° Average value of (A) ((A) _0° +A _45° +A _90° )/3)。

2. The copper alloy sheet according to claim 1, wherein the cross section S _0° Average crystal grain diameter D in the rolling direction of (1) _0° Is 15.0 μm or less.

3. Copper alloy sheet according to claim 1 or 2,

said section S _0° Average KAM value E in _0° The section S _45° Average KAM value E in _45° And the section S _90° Average KAM value E in _90° All are 10.0 DEG or less, and E _0° Standard deviation of (E), E _45° Standard deviation of (1) and (E) _90° Has an average value of standard deviation of 3.0 DEG or less,

the average KAM value E represented by the following formula (2) _0° Degree of anisotropy F of _0° The average KAM value E _45° Degree of anisotropy F of _45° And the average KAM value E _90° Degree of anisotropy F of _90° All of them are below 10.0 percent,

F _m ＝100×(E _m -G)/G … … formula (2)

Wherein in the formula (2), m is 0 degrees, 45 degrees or 90 degrees, and G is E _0° 、E _45° And E _90° Average value of ((E) _0° +E _45° +E _90° )/3)。

4. A copper alloy sheet material characterized by having the following alloy composition: contains 0.10 to 0.80 mass% of Cr, and the balance of Cu and unavoidable impurities,

a tensile strength of 350MPa to 800MPa,

the electrical conductivity is more than 55% IACS and less than 90% IACS,

a section S cut in the direction of 0 DEG with respect to the rolling direction _0° Average KAM value E in _0° A section S cut in the direction of 45 DEG _45° Average KAM value E in _45° And a cross section S cut in the direction of 90 DEG _90° Average KAM value E in _90° All are 10.0 DEG or less, and E _0° Standard deviation of (E), E _45° Standard deviation of (1) and (E) _90° Has an average value of standard deviation of 3.0 DEG or less,

the average KAM value E represented by the following formula (2) _0° Degree of anisotropy F of _0° The average KAM value E _45° Degree of anisotropy F of _45° And the average KAM value E _90° Degree of anisotropy F of _90° All of them are below 10.0 percent,

F _m ＝100×(E _m -G)/G … … formula (2)

Wherein in the formula (2), m is 0 degrees, 45 degrees or 90 degrees, and G is E _0° 、E _45° And E _90° Average value of ((E) _0° +E _45° +E _90° )/3)。

5. The copper alloy sheet according to any one of claims 1 to 4, wherein the alloy composition further contains 0.05 to 2.50 mass% in total of 1 or more elements selected from the group consisting of Mg, Ti, Co, Zr, Zn, Sn and Si.

6. The copper alloy sheet according to any one of claims 1 to 5, wherein the thickness is 0.05mm or more and 0.50mm or less.

7. A method for producing a copper alloy sheet material according to any one of claims 1 to 6, wherein the copper alloy sheet material is produced by a method comprising the steps of,

a copper alloy material is subjected to a casting step (step 1), a homogenization heat treatment step (step 2), a hot rolling step (step 3), a surface cutting step (step 4), a cold rolling step (step 5), an intermediate heat treatment step (step 6), a cold finish rolling step (step 7), and a temper annealing step (step 8) in this order,

the ratio (T6/R5) of the highest temperature T6 (DEG C) of the heat-treated material in the intermediate heat treatment step (step 6) to the reduction ratio R5 (%) of the rolled material in the cold rolling step (step 5) is 8.0 to 20.0,

the maximum temperature T6 is 400-650 ℃,

the ratio (T8/M7) of the maximum temperature T8 (DEG C) of the annealed material in the thermal refining annealing step (step 8) to the average M7 of each pass of the roll gap shape ratio represented by the following formula (3) of the pair of work rolls provided in each pass of the cold finish rolling step (step 7) is 10.0 to 100.0,

the maximum temperature T8 is above 250 ℃ and below 700 ℃,

M7＝3×{r(h ₁ -h ₂ )} ^1/2 /{n(h ₁ +2h ₂ ) … … type (3)

Wherein in the formula (3), r is the radius (mm) of the working roll, h ₁ The thickness (mm), h) of the rolled material before each pass of the cold finish rolling step (step 7) ₂ N is the total number of passes of the cold finish rolling step (step 7), and is the thickness (mm) of the rolled material after each pass of the cold finish rolling step (step 7).

8. A member for electric/electronic parts, characterized in that the copper alloy sheet material according to any one of claims 1 to 6 has burring holes.

9. The electrical/electronic component member according to claim 8, wherein the burring hole has a hole expansion ratio λ represented by the following formula (4) of 20% or more,

λ＝100×(d―d ₀ )/d ₀ … … type (4)

Wherein, in the formula (4), d ₀ The diameter (mm) of the hole before reaming is adopted, and the diameter (mm) of the flanging hole after reaming is adopted.

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