JP7038879B1 - Cu-Ti copper alloy plate material, its manufacturing method, and current-carrying parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-strength Cu—Ti copper alloy plate material having good drawability and more preferably maintained with high bending workability. SOLUTION: The mass is Ti: 1.0 to 5.0%, and Ag, Al, B, Be, Co, Cr, Fe, Mg, Mn, Ni, P, S, Si, Sn, V. , Zn, Zr having an appropriate amount of one or more, and an orientation from the S orientation {231} <3-46> measured by EBSD (electron backscatter diffraction method) of the observation surface parallel to the plate surface. Area of area within 10 ° difference AS, area of area within 10 ° orientation difference from AS and R orientation {132} <4-21> Area within 10 ° orientation difference from AR and P orientation {011} <1-11> The A value determined by the following equation, A = (AS + AR) / (AP + AC) is 0.5 to 20 depending on the area AC of the area AP and the area AC in the region where the orientation difference is within 10 ° from the Cube orientation {001} <100>. Copper alloy plate material. [Selection diagram] None

Description

The present invention relates to a Cu—Ti copper alloy plate material having improved drawability, a method for producing the same, and an energizing component using the plate material as a material.

The Cu—Ti copper alloy (titanium copper) has a high strength level and good stress relaxation resistance among various copper alloys. Since technologies for improving ductility, bending workability, fatigue characteristics, etc. have been developed while maintaining the high strength, Cu-Ti copper alloys are widely used as energizing parts such as connectors, relays, switches, and spring parts. Has come to be done.

Patent Documents 1 and 2 disclose a technique for improving the balance between strength and ductility by setting the area ratio and morphology of the grain boundary reaction phase in a predetermined range in a Cu—Ti copper alloy. The ductility is evaluated by the elongation at break in the tensile test.

Patent Document 3 discloses a technique for improving the strength and bending workability of a Cu—Ti copper alloy by controlling the accumulation ratio of the Cube orientation within a specific range.

Patent Document 4 discloses a technique for improving the strength and bending workability of a Cu—Ti copper alloy by controlling the texture of the {200} crystal plane on the plate surface to have a high X-ray diffraction intensity in the Cube orientation. Has been done.

Patent Document 5 discloses a technique for improving fatigue characteristics in a Cu—Ti copper alloy by limiting the abundance ratio of crystal grain boundaries having relatively coarse grain boundary reaction phases.

On the other hand, in recent years, with the increasing performance and functionality of electronic terminal devices such as smartphones, the materials for energizing parts and spring parts used for them are required to have better workability than before. It has become like. For example, in addition to bending workability, there are increasing cases where drawing workability and overhanging workability are also regarded as important. Patent Document 6 discloses a technique for improving drawability by increasing the Rankford value in a Cu—Co—Si based copper alloy.

JP 2015-140476A JP 2015-140477 WO2012 / 029717 Gazette Japanese Unexamined Patent Publication No. 2011-26635 Japanese Unexamined Patent Publication No. 2017-39959 JP-A-2015-28201

As described above, Cu—Ti copper alloys are copper alloys that originally have a high strength level and can be provided with relatively good bending workability, but there is room for improvement in draw workability. .. With the techniques described in Patent Documents 1 to 5, it is possible to achieve both the strength of the Cu—Ti copper alloy and the ductility, bending workability or fatigue characteristics, but the drawing workability should be sufficiently improved. It is difficult. In particular, it is more difficult to stably improve the drawability while maintaining excellent bending workability. On the other hand, the technique relating to the Cu—Co—Si copper alloy of Patent Document 6 cannot be used as a means for improving the drawability of the Cu—Ti copper alloy. Since the alloy system is different between the Cu—Co—Si copper alloy and the Cu—Ti copper, it is considered that the conditions for controlling the texture suitable for drawing may be different.

In view of the above problems, the present invention provides a Cu—Ti copper alloy plate material having improved drawability. In particular, a Cu—Ti copper alloy plate material having high strength and excellent bending workability and improved drawability is provided.

As a result of detailed studies, the inventors have found that it is possible to improve the drawability by strictly controlling the crystal orientation of the Cu—Ti copper alloy plate material. Specifically, the present specification discloses the following inventions.

[1] In terms of mass%, Ti: 1.0 to 5.0%, Ag: 0 to 0.30%, Al: 0 to 1.0%, B: 0 to 0.20%, Be: 0 to 0. .15%, Co: 0 to 1.0%, Cr: 0 to 1.0%, Fe: 0 to 1.0%, Mg: 0 to 1.0%, Mn: 0 to 1.0%, Ni : 0 to 1.5%, P: 0 to 0.20%, S: 0 to 0.20%, Si: 0 to 1.0%, Sn: 0 to 1.2%, V: 0 to 1. 0%, Zn: 0 to 2.0%, Zr: 0 to 1.0%, and among the above elements, Ag, Al, B, Be, Co, Cr, Fe, Mg, Mn, Ni, P, S , Si, Sn, V, Zn and Zr total content is 3.0% or less, has a composition consisting of the balance Cu and unavoidable impurities, and has a measurement region provided on an observation surface parallel to the plate surface. In EBSD (Electron Backscatter Diffraction) measurement, the area of the region where the crystal orientation difference from the S orientation {2 3 1} <3 -4 6> is within 10 ° is the AS, R orientation {1 3 2} < The area of the region where the crystal orientation difference from 4-2 1> is within 10 ° is the area of the region where the crystal orientation difference from the AR and P orientation {0 1 1} <1-1 1> is within 10 °. When the area of the region where the crystal orientation difference from AP and Cube orientation {0 0 1} <1 0 0> is within 10 ° is AC, the A value according to the following equation (1) is 0.5 to 20. Copper alloy plate material.
A = (AS + AR) / (AP + AC) ... (1)
[2] In the EBSD measurement of the observation surface parallel to the plate surface, the average crystal grain size by the Area Fraction method is 2.0 to 30.0 μm when the boundary where the crystal orientation difference exceeds 5 ° is regarded as the grain boundary. The copper alloy plate material according to the above [1].
[3] The ratio MBR / t of the minimum bending radius MBR that does not cause cracking and the plate thickness t is 2.5 or less according to the W bending test at BW according to the technical standard JCBA T307: 2007 of the Japan Copper and Brass Association. The copper alloy plate material according to the above [1] or [2].
[4] Any of the above [1] to [3] in which the number density of the second phase particles having a particle diameter of 0.1 μm or more existing in the matrix (metal base) is 5 × 10 ⁵ particles / mm ² or less. The copper alloy plate material described.
[5] The copper alloy plate material according to any one of the above [1] to [4], wherein the tensile strength in the rolling direction is 850 MPa or more.
[6] The copper alloy plate material according to any one of the above [1] to [5], which has a plate thickness of 0.02 to 0.50 mm.
[7] An energizing component using the copper alloy plate material according to any one of the above [1] to [6] as a material.
[8] A step of cold-rolling a hot-worked material having the composition described in the above [1] with a rolling ratio of 50 to 99%.
After the first heat treatment held at 380 to 620 ° C. for 1 to 20 hours, the second heat treatment held at 180 to 420 ° C. for 1 to 20 hours is performed under the conditions according to the following formula (3).
The process of cold rolling with a rolling ratio of 10 to 99% and
A step of performing solution treatment under the condition of heating to 700 to 950 ° C. with a tension of 12.5 to 20.0 N / mm ² applied in the rolling direction of the plate material.
The process of aging treatment under the condition of holding at 300 to 600 ° C for 1 hour or more, and
The method for producing a copper alloy plate according to any one of the above [1] to [6], which comprises the above in the above order.
T1 ≧ T2 + 40 ℃… (3)
Here, T1 is the holding temperature (° C.) of the first heat treatment, and T2 is the holding temperature (° C.) of the second heat treatment.
[9] The method for producing a copper alloy plate material according to the above [8], wherein cold rolling with a rolling ratio of 70% or less is performed between the first heat treatment and the second heat treatment.
[10] The method for producing a copper alloy plate material according to the above [8] or [9], wherein cold rolling with a rolling ratio of 60% or less is performed between the solution treatment and the aging treatment.
[11] After the aging process,
The process of cold rolling with a rolling ratio of 60% or less, and
The process of low-temperature annealing that is held at 300 to 620 ° C for a time of 600 seconds or less, and
The method for producing a copper alloy plate according to any one of the above [8] to [10], which comprises the above in the above order.

In the present specification, the "plate material" means a sheet-shaped metal material formed by utilizing the malleability of the metal. A thin sheet-shaped metal material is sometimes called a "foil", and such a "foil" is also included in the "plate material" here. A long sheet-like metal material wound into a coil is also included in the "plate material". In the present specification, the thickness of the sheet-shaped metal material is referred to as "plate thickness". Further, the "plate surface" is a surface perpendicular to the plate thickness direction of the plate material. The "plate surface" is sometimes called the "rolled surface".

The notation of the crystal orientation {hkl} <uvw> means that the {hkl} plane of the crystal is parallel to the plate surface (rolled plane) and the <uvw> direction of the crystal is parallel to the rolling direction. The crystal structure of the copper alloy targeted in the present invention is fcc (face-centered cubic lattice). The exponents of h, k, l, and u, v, w are indices of crystals based on a unit cell having an fcc structure. The average crystal grain size and the above areas AS, AR, AP, and AC by EBSD (electron backscatter diffraction method) can be obtained as follows.

[How to obtain average crystal grain size and area AS, AR, AP, AC by EBSD]
The plate surface (rolled surface) of the plate material sample to be measured is buffed and then smoothed by ion milling to obtain an observation surface. An observation area (for example, a rectangular area of 240 × 180 μm) having a visual field corresponding to an observation magnification of 500 times is randomly set in the observation surface, and the step size of the observation area is set to 0 by EBSD (electron backscatter diffraction method). An electron beam is irradiated at 5 μm, and an attempt is made to measure the average crystal grain size by the Area Fraction method when the boundary where the crystal orientation difference between adjacent measurement points exceeds 5 ° is regarded as the grain boundary (this is the “initial magnification”. Measurement at ".). At that time, for crystal grains in which a part of the crystal grains protrudes from the boundary line of the measurement region, the boundary line is regarded as a part of the crystal grain boundary and included in the measurement target of the crystal grain size. The twin boundary is also treated as a grain boundary. In addition, using the EBSD data analysis software, the area of the region where the crystal orientation difference from the S orientation {2 3 1} <3 -4 6> is within 10 ° in the measurement region is AS and R orientation { The area of the region where the crystal orientation difference from 1 3 2} <4-2 1> is within 10 ° is the AR, and the crystal orientation difference from P orientation {0 1 1} <1-1 1> is within 10 °. The area of a certain region is AP, and the area AC of the region where the crystal orientation difference from the Cube orientation {0 0 1} <1 0 0> is within 10 ° is calculated.
If the average crystal grain size determined by measurement at the initial magnification is in the range of more than 5.0 μm and less than 20.0 μm, the average crystal grain size and area AS determined by the above step size by measurement at the initial magnification, The values of AR, AP, and AC are adopted as the average crystal grain size and area AS, AR, AP, and AC for the sample, respectively.

(Measurement at correction magnification)
If the average crystal grain size is 5.0 μm or less in the above measurement at the initial magnification, the step size is changed from 0.5 μm to 0.1 μm and the observation area of the visual field corresponding to the observation magnification of 2500 times (for example). The average crystal grain size is remeasured in the same manner for a rectangular region of 36 × 48 μm), and the areas AS, AR, AP, and AC are recalculated from the data at each measurement point.
As a result, when the average crystal grain size is 3.0 μm or less, the step size is further changed from 0.1 μm to 0.05 μm, and the observation region of the visual field corresponding to the observation magnification of 5000 times (for example, 18 × 24 μm). The average crystal grain size is remeasured in the same manner for the rectangular region), and the areas AS, AR, AP, and AC are recalculated from the data at each measurement point.
On the other hand, when the average crystal grain size is 20.0 μm or more in the measurement at the above initial magnification, the step size is changed from 0.5 μm to 1.0 μm and the observation area of the visual field corresponding to the observation magnification of 200 times. The average crystal grain size is remeasured in the same manner for (for example, a rectangular region of 450 × 600 μm), and the areas AS, AR, AP, and AC are recalculated from the data at each measurement point.
If the average crystal grain size obtained by measurement at the initial magnification is not in the range of more than 5.0 μm and less than 20.0 μm, then by the measurement at the last set magnification as described above, at that time. The average crystal grain size and area AS, AR, AP, and AC values obtained at the set step size are adopted as the average crystal grain size and area AS, AR, AP, and AC for the sample, respectively.

EBSD measurement by the above method was performed for 5 or more different observation regions randomly set in the observation plane that do not overlap with each other, and the average crystal grain size and area AS of each of the 5 or more observation regions obtained in total. The arithmetic mean values for the AR, AP, and AC values are calculated, and the arithmetic mean values are defined as the average crystal grain size (μm) and area AS, AR, AP, and AC of the plate material sample. Here, the unit of the area AS, AR, AP, and AC may be expressed as an area ratio (%) obtained by converting the value of the actual area (for example, μm ² ) into the ratio of the total area of the observation area. If an overlapping portion occurs in the mapping area corresponding to each of the areas AS, AR, AP, and AC, the overlapping portion is also independently added to the calculation of the area.

[How to find the number density of second phase particles]
The plate surface (rolled surface) is electropolished to dissolve only the Cu substrate to prepare an observation surface on which the second phase particles are exposed, and the observation surface is observed by SEM at a magnification of 10,000 times, and SEM. The value obtained by dividing the total number of second-phase particles with a major axis of 0.1 μm or more observed on the image by the total observed area (mm ² ) is defined as the second-phase particle number density (pieces / mm ² ). However, the total observation area shall be 0.001 mm ² or more in total based on a plurality of non-overlapping observation fields set at random. The second phase particles partially protruding from the observation field of view are counted if the major axis of the part appearing in the observation field of view is 0.05 μm or more. Here, the "major axis" of a certain particle is the length of the longest line segment among the line segments connecting arbitrary two points on the outer edge of the particle on the SEM image.

FIG. 1 illustrates an SEM image of the above observation surface. The length of the white scale bar displayed at the bottom of this image corresponds to 1 μm. There are two types of second phase particles, "granular precipitates" and "grain boundary reaction phases". The grain boundary reaction phase is formed by a group of adjacent layered particles. The appearance of the grain boundary reaction phase that appears on the observation surface differs depending on the angle at which the observation surface cuts a group of layered particles. In the case of grain boundary reaction phase type second phase particles, the region on the image where a group of layered particles exists is regarded as one particle, and the major axis is determined by the method according to the above "How to determine the number density of second phase particles". stipulate. In the example of FIG. 1, the existence range of a group of particles in the ellipse indicated by reference numeral A is regarded as one second phase particle.

According to the present invention, it is possible to provide a high-strength Cu—Ti copper alloy plate material with improved drawability. This Cu—Ti copper alloy plate material is also excellent in bending workability. Therefore, the present invention can contribute to the industrial spread of Cu—Ti copper alloys as materials for energizing parts and spring parts that require excellent workability into complicated shapes.

An SEM photograph of a portion where a grain boundary reaction phase is generated on an observation surface prepared by electropolishing the plate surface of a Cu—Ti alloy plate material.

[Chemical composition]
A Cu—Ti copper alloy is applied to the plate material of the present invention. Hereinafter, "%" regarding the alloy component means "mass%" unless otherwise specified.

Ti is an element that contributes to an increase in strength by forming a modulated structure of Ti by spinodal decomposition and forming fine second-phase particles by precipitation. It also contributes to the improvement of stress relaxation resistance. Here, alloys having a Ti content of 1.0% or more are targeted. More preferably, it is 2.0% or more. Excessive Ti content is a factor that lowers hot workability and cold workability, and also causes a factor that narrows the appropriate temperature range for solution treatment. Therefore, the Ti content is set to 5.0% or less. It may be controlled to 4.0% or less, or 3.5% or less.

Ag, Al, B, Be, Co, Cr, Fe, Mg, Mn, Ni, P, S, Si, Sn, V, Zn and Zr are arbitrary elements. One or more of these can be contained as needed. For example, Ni, Co, and Fe form an intermetallic compound with Ti and contribute to the improvement of strength. In addition, since the intermetallic compounds of these elements suppress the coarsening of crystal grains, solution treatment in a higher temperature range becomes possible, which is advantageous in sufficiently solid-solving Ti. Sn has a solid solution strengthening action and a stress relaxation resistance improving action. Zn not only improves solderability and strength, but is also effective in improving castability. Mg has an action of improving stress relaxation resistance and an action of removing S. Al and Si can form a compound with Ti. Cr and Zr are effective in strengthening dispersion and suppressing coarsening of crystal grains. Since Mn and V easily form a refractory compound with S and the like, and B and P have the effect of refining the cast structure, they can each contribute to the improvement of hot workability.

The contents of the above optional elements are Ag: 0 to 0.30%, Al: 0 to 1.0%, B: 0 to 0.20%, Be: 0 to 0.15%, Co: 0 to 1. 0%, Cr: 0 to 1.0%, Fe: 0 to 1.0%, Mg: 0 to 1.0%, Mn: 0 to 1.0%, Ni: 0 to 1.5%, P: 0 to 0.20%, S: 0 to 0.20%, Si: 0 to 1.0%, Sn: 0 to 1.2%, V: 0 to 1.0%, Zn: 0 to 2.0 %, Zr: preferably in the range of 0 to 1.0%. Further, the total content of Ag, Al, B, Be, Co, Cr, Fe, Mg, Mn, Ni, P, S, Si, Sn, V, Zn and Zr among the above elements is 3.0% or less. It is preferably 1.0% or less, and may be controlled to 0.5% or less.

[Crystal orientation]
According to a detailed study by the inventors, it has been found that the drawability can be improved by strictly controlling the texture of the Cu—Ti copper alloy plate material. Specifically, the crystal orientation in which the A value represented by the following equation (1) is 0.5 to 20 is extremely good for significantly improving the drawability of the Cu—Ti copper alloy plate material. It is valid.
A = (AS + AR) / (AP + AC) ... (1)
Here, AS, AR, AP, and AC have the following areas determined by EBSD (Electron Backscatter Diffraction) measurement for the measurement region provided on the observation surface parallel to the plate surface.
AS: Region where the crystal orientation difference from S orientation {2 3 1} <3 -4 6> is within 10 ° AR: Crystal orientation difference from R orientation {1 3 2} <4-2 1> is 10 ° Area within 10 ° Crystal orientation difference from AP: P orientation {0 1 1} <1-1 1> AC: Crystal orientation difference from Cube orientation {0 0 1} <1 0 0> Area within 10 °

The EBSD measurement follows the method described in "How to determine the average crystal grain size and area AS, AR, AP, AC by EBSD" above. The crystal orientation in which the A value is 0.5 to 20 significantly improves the "overhangability", which is an important processing element in improving the drawability. The A value is more preferably 0.5 to 10, and even more preferably 0.5 to 5.

[Average crystal grain size]
It is known that the refinement of crystal grains is advantageous for improving the bending workability and fatigue resistance of Cu—Ti copper alloy plate materials, but the plate material adjusted to the above-mentioned crystal orientation has further drawing workability. It turned out to be advantageous for the improvement of. Here, in the EBSD measurement for the observation surface parallel to the plate surface, the average crystal grain size by the Area Fraction method when the boundary (including the twin boundary) where the crystal orientation difference exceeds 5 ° is regarded as the grain boundary. Is adopted. The average crystal grain size is preferably 2.0 to 30.0 μm, more preferably 2.0 to 15.0 μm, and even more preferably 3.0 to 10.0 μm. The EBSD measurement follows the method described in "How to determine the average crystal grain size and area AS, AR, AP, AC by EBSD" above.

[Second phase particles]
The precipitation phase observed in the metal structure of the Cu—Ti copper alloy is a grain boundary reaction that grows in layers from the crystal grain boundaries to the inside of the crystal grains with the granular precipitates existing in the crystal grains or at the grain boundaries. There is a phase. The second phase particles referred to here include both granular precipitates and intergranular reaction phases. In the case of the grain boundary reaction phase, as described above, the region on the image in which a group of layered particles is present is regarded as one particle. According to the studies by the inventors, in the Cu—Ti copper alloy plate material adjusted to the above-mentioned crystal orientation, the abundance of second-phase particles having a particle diameter (major axis) of 0.1 μm or more can be reduced. It was found to be effective in further improving the drawability. Further, in order to improve the drawability and raise the bending workability to a high level, it is effective to reduce the abundance of the second phase particles having a particle diameter (major diameter) of 0.1 μm or more. .. As a result of various studies, when it is important to achieve both drawability and excellent bending workability, the number density of the second phase particles having a particle diameter (major diameter) of 0.1 μm or more is 5 × 10 ⁵ particles / It is desirable to have a tissue state of mm ² or less. The number density of the second phase particles having a particle diameter (major diameter) of 0.1 μm or more is more preferably 1 × 10 ⁵ particles / mm ² or less, and more preferably 2 × 10 ⁴ particles / mm ² or less. More preferred.

The precipitates constituting the second phase particles include Cu-Ti intermetallic compounds and metals such as Ni-Ti, Co-Ti, and Fe-Ti depending on the type of alloying element to be added. Intermetallic compounds may be present.

[Bending workability]
Bending is often involved in processing current-carrying parts. For Cu-Ti alloys, the ratio MBR / t of the minimum bending radius MBR that does not cause cracking and the plate thickness t is 2 by the W bending test at BW according to the Japan Copper and Brass Association technical standard JCBA T307: 2007. It is preferable to have bending workability of .5 or less. B.W. (Bad Way) means that the bending axis is in the direction parallel to rolling. The MBR / t is more preferably 1.5 or less, and further preferably 0.5 or less.

JCBA T307: 2007 states that "this standard applies to the evaluation of bending workability of copper and copper alloy thin strips with a thickness of 0.1 mm or more and 0.8 mm or less." The bending radius is 0,0. .05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.4, 0.5, 0.6, 0.8, 1.0, 1.2, 1.4 It is stated that it is desirable to select from standard bending radii of 1.6, 1.8 and 2.0 (mm). According to the studies by the inventors, it has been confirmed that even in a Cu—Ti copper alloy plate having a plate thickness of less than 0.1 mm, the bending workability can be evaluated by the W bending test using the above standard bending radius. Was done. Therefore, in the present invention, the W bending test method in BW shown in JCBA T307: 2007 is extended even when the plate thickness is less than 0.1 mm (for example, 0.02 mm or more and less than 0.1 mm). Apply as it is.

[Tensile strength]
The tensile strength in the rolling direction is preferably 850 MPa or more, more preferably 950 MPa or more. It is also possible to adjust the tensile strength in the rolling direction to a strength level of 1100 MPa or more.

[Production method]
The copper alloy plate material described above can be manufactured by, for example, the following manufacturing process.
Melting / casting-> hot working-> cold rolling 1-> first heat treatment-> (cold rolling 2)-> second heat treatment-> cold rolling 3-> solution treatment-> (cold rolling 4)-> aging treatment-> (cold) Rolling 5) → (low temperature annealing)
In the above, the steps in parentheses can be omitted. Although not described in the above steps, surface milling is performed as necessary after hot working, and pickling, polishing, or further degreasing is performed as necessary after each heat treatment. Hereinafter, a manufacturing method suitable for manufacturing a Cu—Ti copper alloy plate having the above-mentioned crystal orientation and excellent bending workability will be disclosed.

[Melting / Casting]
The slab may be manufactured using a crucible furnace or the like. In order to prevent the oxidation of Ti, it is preferable to carry out in an inert gas atmosphere or a vacuum melting furnace.

[Hot working, cold rolling 1]
The slab heating before hot working can be held at, for example, 900 to 960 ° C. for 1 to 5 hours. The method of hot working is not particularly limited. Usually, hot forging and hot rolling are adopted. In the case of hot rolling, the total hot rolling ratio may be, for example, 60 to 97%. After the completion of hot working, it is preferable to quench by water cooling or the like. Then, cold rolling is performed. Cold rolling at this stage is referred to as "cold rolling 1" in the present specification. The rolling ratio in cold rolling 1 can be, for example, 50 to 99%.
Here, the rolling ratio is expressed by the following equation (2).
Rolling rate (%) = 100 × (t ₀ − t ₁ ) / t ₀ … (2)
t ₀ : Plate thickness before rolling (mm)
t ₁ : Plate thickness after rolling (mm)

[1st heat treatment, cold rolling 2, 2nd heat treatment]
Prior to the solution treatment, a two-step heat treatment is performed. The heat treatment in the first stage is called "first heat treatment", and the heat treatment in the second stage is called "second heat treatment". Cold rolling may be performed between the first heat treatment and the second heat treatment, if necessary. Cold rolling at this stage is referred to as "cold rolling 2" in the present specification. Each of these steps is performed under the following conditions.
First heat treatment: Hold at 380 to 620 ° C. for 1 to 20 hours.
Cold rolling 2: If necessary, cold rolling with a rolling ratio of 70% or less is performed. In that case, it is more effective to secure a rolling ratio of 10% or more.
Second heat treatment: Hold at 180 to 420 ° C. for 1 to 20 hours.
However, the holding temperature T1 (° C.) of the first heat treatment and the holding temperature T2 (° C.) of the second heat treatment satisfy the condition of the following equation (3).
T1 ≧ T2 + 40 ℃… (3)
When the cold rolling in the middle is omitted, the first heat treatment and the second heat treatment can be continuously carried out by adopting a heat pattern in which the temperature is lowered in the middle in the same batch heat treatment furnace. In that case, the average cooling rate from T1 (° C.) to T2 (° C.) is preferably 0.5 ° C./min or more.

The size and number of precipitates can be controlled by the two-step heat treatment under the above conditions. Further, finally, the crystal orientation satisfying the above-mentioned equation (1) can be realized. Therefore, this two-step heat treatment is an extremely effective step for obtaining a Cu—Ti copper alloy plate material having high levels of strength, bending workability, and draw workability.

[Cold rolling 3]
Cold rolling is performed before the solution treatment to introduce lattice strain. Cold rolling at this stage is referred to as "cold rolling 3" in the present specification. The rolling ratio in the cold rolling 3 can be in the range of 10 to 99%, preferably 70% or more.

[Soluble treatment, cold rolling 4]
The solution treatment is performed under the condition of heating to 700 to 950 ° C. with a tension of 12.5 to 20.0 N / mm ² applied in the rolling direction of the plate material. The holding time at 700 to 950 ° C. is preferably 10 to 300 seconds. In the plate material that has undergone the above-mentioned two-step heat treatment, the crystal orientation that finally satisfies the equation (1) can be realized by applying the above tension in the solution heat treatment and introducing an appropriate stress. The tension can be controlled, for example, by the driving force of the bridle rolls at both ends of the heating zone while passing through a continuous annealing furnace.

After the solution treatment, cold rolling can be performed in a rolling ratio of 60% or less, if necessary. In that case, it is more effective to secure a rolling ratio of 10% or more. Cold rolling at this stage is referred to as "cold rolling 4" in the present specification.

[Aging process]
Next, aging treatment is performed under the condition of holding at 300 to 600 ° C. for 1 hour or more. Usually, the optimum aging processing conditions can be set within a holding time of 24 hours or less.

[Cold rolling 5, low temperature annealing]
After the aging treatment, cold rolling and low temperature annealing can be performed as needed. Cold rolling at this stage is referred to as "cold rolling 5" in the present specification. In cold rolling 5 (finish cold rolling), the rolling ratio needs to be 60% or less, and may be controlled within the range of 50% or less, or 30% or less. Further, it is more effective to secure a rolling ratio of 10% or more in the cold rolling 5. The low temperature annealing can be performed under the condition of holding at 300 to 620 ° C. for a time of 600 seconds or less. It is more effective to secure a holding time of 15 seconds or more in the above temperature range.
The final plate thickness can be, for example, in the range of 0.02 to 0.50 mm.

A copper alloy having the chemical composition shown in Table 1 was melted and cast. The obtained slab was heated at 940 ° C. for 1 hour, extracted, hot-rolled, and water-cooled. The total hot rolling ratio is 80 to 95%. After hot rolling, the oxide layer on the surface was removed (face-cut) by mechanical polishing to obtain a hot-rolled material having a plate thickness of 10 mm. Each hot-rolled material was cold-rolled under the conditions described in the column of "cold rolling 1" in Tables 2 and 3.

Then, except for some examples (Comparative Examples 34, 43 to 45), the first heat treatment and the second heat treatment were performed under the conditions shown in Tables 2 and 3. Between the first heat treatment and the second heat treatment, cold rolling was performed under the conditions described in the column of "cold rolling 2" in Tables 2 and 3 as necessary. The example in which the column of rolling ratio is displayed as "-" (hyphen) means that the cold rolling is omitted (the same applies to "cold rolling 4" and "cold rolling 5" below). In Comparative Example 34, the first heat treatment and the second heat treatment were omitted. In Comparative Examples 43 to 45, the second heat treatment was omitted. The first heat treatment and the second heat treatment were performed in a nitrogen atmosphere using a batch heat treatment furnace, except for some examples (Comparative Examples 42 to 44). In Comparative Examples 42 to 44, a continuous annealing furnace was used. Of these, in the first heat treatment in Comparative Example 44, a heat pattern was adopted in which the material temperature reached 700 ° C. and then immediately cooled. In the case where the intermediate cold rolling (cold rolling 2) between the first heat treatment and the second heat treatment is omitted, the first heat treatment and the second heat treatment are performed in the same furnace except for some examples (Comparative Example 31). I went on. In that case, a heat pattern was adopted in which the average cooling rate was 0.5 to 10 ° C./min from the holding temperature of the first heat treatment to the holding temperature of the second heat treatment. In Comparative Example 31, the material was once taken out of the furnace after the first heat treatment, and then charged into the furnace again to attempt two heat treatments at the same holding temperature (300 ° C.).

Then, cold rolling was performed under the conditions described in the column of "cold rolling 3" in Tables 2 and 3. Then, the solution treatment was performed under the conditions shown in Tables 2 and 3. The solution treatment was carried out using a continuous annealing furnace. At that time, the tension was controlled by the driving force of the bridle rolls at both ends of the heating zone of the continuous heat treatment furnace.

After the solution treatment, cold rolling was performed under the conditions described in the column of "cold rolling 4" in Tables 2 and 3, if necessary. Then, the aging treatment was performed under the conditions shown in Tables 2 and 3. The aging treatment was carried out in a nitrogen atmosphere using a batch heat treatment furnace.

After the aging treatment, except for some examples (Example 2 of the present invention, Comparative Example 36), cold rolling was performed under the conditions described in the column of "cold rolling 5" in Tables 2 and 3, and then Table 2 and Table 3. Low temperature annealing was performed under the conditions shown in Table 3.
As described above, Cu—Ti copper alloy plate materials having the final plate thicknesses shown in Tables 2 and 3 were obtained. The following investigations were conducted using these plate materials as test materials.

(Average crystal grain size, crystal orientation)
Observation for EBSD measurement by buffing the plate surface (rolled surface) of the sample collected from the test material and then treating it with an ion milling device (SVM-741, manufactured by Sanyu Electronics Co., Ltd.) at an acceleration voltage of 4 kV. A surface was made. The surface of the sample was observed with an FE-SEM (JSM-7200F manufactured by Nippon Denshi Co., Ltd.) at an acceleration voltage of 15 kV, and the EBSD device (Symmetery manufactured by Oxford Instruments) installed in the FE-SEM was used to observe the above. Average crystal grain size and area by EBSD The average crystal grain size and crystal orientation were determined according to "How to determine AS, AR, AP, AC". The A value for evaluating the crystal orientation is expressed as an area ratio (%) converted into the ratio of the above-mentioned areas AS, AR, AP, and AC to the total area of the observation area, and these values are used to represent the above-mentioned (1). It was calculated by the formula. The initial observation magnification was 500 times (the observation range corresponds to 240 × 180 μm), and the measurement step size was 0.5 μm. The observation field of view was 5 randomly selected non-overlapping fields of view. If the average crystal grain size obtained by measurement at the initial magnification exceeds 5.0 μm and falls outside the range of less than 20.0 μm, the average crystal grain size is according to the method shown in “Measurement at modified magnification” above. And the areas AS, AR, AP, AC were defined. The cleanup treatment was performed only once with the Grain Dilation at a deviation angle of 5 ° and a minimum crystal grain size of 2 pixels. As software for EBSD data analysis, OIM-Anysis 7.1.1 manufactured by TSL Solutions Co., Ltd. was used.

(Number density of second phase particles)
The number density of coarse second-phase particles was determined according to the above-mentioned "Method of determining the number density of second-phase particles". Distilled water, phosphoric acid, ethanol, and 2-propanol were mixed at a ratio of 2: 1: 1: 1 as the electrolytic polishing liquid for preparing the observation surface. The electropolishing was carried out using an electropolishing apparatus (Electromet 4) manufactured by BUEHLER under the conditions of a voltage of 15 V and a time of 20 seconds. The sample surface was observed by FE-SEM (JSM-7200F, manufactured by JEOL Ltd.) at a magnification of 10,000 times. The observation field of view was 10 randomly selected non-overlapping fields of view. The total observation area of 10 fields of view is 0.001038 mm ² . The number density (pieces / mm ² ) of the second phase particles was obtained by dividing the total number of the second phase particles having a major axis of 0.1 μm or more counted in each observation field by the total observation area.

(Bending workability)
The ratio MBR / t of the minimum bending radius MBR without cracking and the plate thickness t was determined by the W bending test in BW according to the technical standard JCBA T307: 2007 of the Japan Copper and Brass Association. The size of the test piece was 30 mm in the direction perpendicular to the rolling direction and 10 mm in the rolling direction. For the bending radius, the standard bending radius described in JCBA T307: 2007 was adopted. The test was performed for one bending radius with the number of tests n = 3, and the minimum standard bending radius in which no crack was observed on the surface of the bent portion in all three test pieces was defined as the MBR for the test material. The presence or absence of cracks on the surface of the bent portion was determined according to JCBA T307: 2007. For the sample judged to be "wrinkle: large" in the appearance observation of the bent part surface, prepare a sample cut perpendicular to the bending axis direction for the deepest wrinkle part, and observe the polished cross section with an optical microscope. It was confirmed whether or not cracks extending to the inside of the plate thickness had occurred, and if such cracks did not occur, it was determined that "no cracks were observed".
The results are represented by the following evaluation symbols, and those with a △ evaluation or higher were judged to be acceptable.
Evaluation symbol MBR / t range ◎ 0.5 or less ○ More than 0.5 and 1.5 or less △ More than 1.5 and 2.5 or less × More than 2.5

(Tensile strength)
Tensile test pieces (JIS No. 5) in the rolling direction (LD) were collected from each test material, and a tensile test was performed in accordance with JIS Z2241 with the number of tests n = 3, and the tensile strength was measured. The average value of n = 3 was used as the performance value of the test material.

(conductivity)
The conductivity of each test material was measured by a double bridge and average cross-sectional area method according to JIS H0505.

(Eriksen value)
In order to improve the drawability of the Cu—Ti copper alloy plate, it is extremely important to improve the overhanging element of the draw. Here, the drawability was evaluated by investigating how much the overhang workability was improved by the Eriksen test according to the technical standard JCBA T319: 2003 of the Japan Copper and Brass Association. JCBA T319: 2003 states, "This standard specifies a test method and a testing machine for measuring the Eriksen value of a thin metal plate having a thickness of 0.1 to 2 mm." According to the study by the inventors, even for Cu—Ti copper alloy plates with a plate thickness of less than 0.1 mm, the drawability of Cu—Ti copper alloy plates should be evaluated by the Ericssen test according to the standard. Was confirmed to be possible. The test was carried out with the number of tests n = 3, the average value of the Eriksen values of 3 times was used as the grade value of the test material, the results were represented by the following evaluation symbols, and those with ○ evaluation or higher were judged to be acceptable.
Evaluation symbol Eriksen value range ◎ 6.0 or more ○ 3.0 or more and less than 6.0 × 1.5 or more and less than 3.0 × × Less than 1.5 The results of Table 4 and Table 5 are shown.

All of the plate materials of the present invention in which the chemical composition and the production conditions are strictly controlled according to the above-mentioned regulations have a crystal orientation in which the A value satisfies the specified range of the present invention, and the evaluation of drawability by the Elixin value is good. there were. In addition, the strength level was high and the bending workability was excellent. On the other hand, the plate material of the comparative example in which the A value was out of the specified range of the present invention was not found to have an effect of improving the drawability.

The main factors that the A value is out of the specified range of the present invention in each comparative example are as follows.
No.31: The holding temperature of the first heat treatment was too low.
No. 32: The holding temperature of the second heat treatment was too high.
No.33: The holding temperature of the second heat treatment was too low.
No. 34: The first heat treatment and the second heat treatment were not performed.
No.35: The tension in the solution treatment was too high.
No. 36: The holding temperature of the first heat treatment was too high.
No.37: The holding temperature of the first heat treatment was too high.
No.38: The Ti content was too high.
No.39: The Ti content was too low.
No.40: The tension in the solution treatment was too low.
No. 41: The temperature of the solution treatment was too high.
No. 42: The holding time of the first heat treatment was too short. The holding temperature of the second heat treatment was too high and the holding time was too short. The tension in the solution treatment was too low.
No.43: The holding temperature of the first heat treatment was too high, and the holding time was too short. No second heat treatment was performed. The tension in the solution treatment was too low.
No.44: The holding temperature of the first heat treatment was too high, and the holding time was too short. No second heat treatment was performed. The tension in the solution treatment was too low.
No.45: The second heat treatment was not performed. The tension in the solution treatment was too low.
No.46: The tension in the solution treatment was too low.
No. 47: The holding temperature of the first heat treatment was too high. The tension in the solution treatment was too low.

Claims (11)

By mass%, Ti: 1.0 to 5.0%, Ag: 0 to 0.30%, Al: 0 to 1.0%, B: 0 to 0.20%, Be: 0 to 0.15%. , Co: 0 to 1.0%, Cr: 0 to 1.0%, Fe: 0 to 1.0%, Mg: 0 to 1.0%, Mn: 0 to 1.0%, Ni: 0 to 1.5%, P: 0 to 0.20%, S: 0 to 0.20%, Si: 0 to 1.0%, Sn: 0 to 1.2%, V: 0 to 1.0%, Zn: 0 to 2.0%, Zr: 0 to 1.0%, and among the above elements, Ag, Al, B, Be, Co, Cr, Fe, Mg, Mn, Ni, P, S, Si, The total content of Sn, V, Zn and Zr is 3.0% or less, the composition is composed of the balance Cu and unavoidable impurities, and the EBSD (electron) for the measurement region provided on the observation surface parallel to the plate surface. In the electron backscatter diffraction method) measurement, the area of the region where the crystal orientation difference from the S orientation {2 3 1} <3 -4 6> is within 10 ° is the AS, and the R orientation {1 3 2} <4-2. The area of the region where the crystal orientation difference from 1> is within 10 ° is AR, and the area of the region where the crystal orientation difference from P orientation {0 1 1} <1-1 1> is within 10 ° is AP, Cube. A copper alloy plate material having an A value of 0.5 to 20 according to the following equation (1), where AC is the area of the region where the crystal orientation difference from the orientation {0 0 1} <1 0 0> is within 10 °. ..
A = (AS + AR) / (AP + AC) ... (1) Claimed that the average crystal grain size by the Area Fraction method is 2.0 to 30.0 μm when the boundary where the crystal orientation difference exceeds 5 ° is regarded as the grain boundary in the EBSD measurement of the observation surface parallel to the plate surface. Item 1. The copper alloy plate material according to Item 1. Claim 1 in which the ratio MBR / t of the minimum bending radius MBR without cracking and the plate thickness t is 2.5 or less according to the W bending test in BW according to the technical standard JCBA T307: 2007 of the Japan Copper and Brass Association. Or the copper alloy plate material according to 2. The copper alloy according to any one of claims 1 to 3, wherein the number of second-phase particles having a particle diameter of 0.1 μm or more present in the matrix (metal substrate) is 5 × 10 ⁵ particles / mm ² or less. Plate material. The copper alloy plate material according to any one of claims 1 to 4, wherein the tensile strength in the rolling direction is 850 MPa or more. The copper alloy plate material according to any one of claims 1 to 5, wherein the plate thickness is 0.02 to 0.50 mm. An energizing component using the copper alloy plate material according to any one of claims 1 to 6 as a material. By mass%, Ti: 1.0 to 5.0%, Ag: 0 to 0.30%, Al: 0 to 1.0%, B: 0 to 0.20%, Be: 0 to 0.15%. , Co: 0 to 1.0%, Cr: 0 to 1.0%, Fe: 0 to 1.0%, Mg: 0 to 1.0%, Mn: 0 to 1.0%, Ni: 0 to 1.5%, P: 0 to 0.20%, S: 0 to 0.20%, Si: 0 to 1.0%, Sn: 0 to 1.2%, V: 0 to 1.0%, Zn: 0 to 2.0%, Zr: 0 to 1.0%, and among the above elements, Ag, Al, B, Be, Co, Cr, Fe, Mg, Mn, Ni, P, S, Si, A step of cold rolling a hot-worked material having a total content of Sn, V, Zn and Zr of 3.0% or less and a composition consisting of the balance Cu and unavoidable impurities with a rolling ratio of 50 to 99%. When,
After the first heat treatment held at 380 to 620 ° C. for 1 to 20 hours, the second heat treatment held at 180 to 420 ° C. for 1 to 20 hours is performed under the conditions according to the following formula (3).
The process of cold rolling with a rolling ratio of 10 to 99% and
A step of performing solution treatment under the condition of heating to 700 to 950 ° C. with a tension of 12.5 to 20.0 N / mm ² applied in the rolling direction of the plate material.
The process of aging treatment under the condition of holding at 300 to 600 ° C for 1 hour or more, and
The method for producing a copper alloy plate material according to any one of claims 1 to 6, further comprising the above-mentioned order.
T1 ≧ T2 + 40 ℃… (3)
Here, T1 is the holding temperature (° C.) of the first heat treatment, and T2 is the holding temperature (° C.) of the second heat treatment. The method for producing a copper alloy plate material according to claim 8, wherein cold rolling with a rolling ratio of 70% or less is performed between the first heat treatment and the second heat treatment. The method for producing a copper alloy plate material according to claim 8 or 9, wherein cold rolling with a rolling ratio of 60% or less is performed between the solution treatment and the aging treatment. After the aging process,
The process of cold rolling with a rolling ratio of 60% or less, and
The process of low-temperature annealing that is held at 300 to 620 ° C for a time of 600 seconds or less, and
The method for producing a copper alloy plate material according to any one of claims 8 to 10, further comprising the above items in the above order.

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