JP5449595B1 - Copper alloy sheet with excellent conductivity and bending deflection coefficient - Google Patents

Abstract

A copper alloy plate having high strength, high conductivity, a high bending deflection coefficient and excellent stress relaxation characteristics, and a high-current electronic component and a heat dissipation electronic component using the copper alloy are provided.
One or two of Zr and Ti are contained in a total of 0.01 to 0.50% by mass, the balance is made of copper and inevitable impurities, and is orthogonal to the sheet width direction (TD) of the rolled material. When the EBSD measurement is performed on the cross section, the area ratio of the crystal whose (122) plane normal and TD form an angle of 10 degrees or less, and the (133) plane normal and TD forms an angle of 10 degrees. It is a copper alloy plate having a total tensile strength of 350 MPa or more with a total area ratio of 10% or more.
[Selection figure] None

Description

  TECHNICAL FIELD The present invention relates to a copper alloy plate and electronic parts for energization or heat dissipation, and in particular, electronic parts such as terminals, connectors, relays, switches, sockets, bus bars, lead frames, heat sinks, etc. mounted on electric machines / electronic devices, automobiles, etc. The present invention relates to a copper alloy plate used as a material for the above and an electronic component using the copper alloy plate. Among them, copper alloys suitable for use in high current electronic parts such as connectors and terminals for large currents used in electric cars, hybrid cars, etc., or for use in electronic parts for heat dissipation such as liquid crystal frames used in smartphones and tablet PCs The present invention relates to a plate and an electronic component using the copper alloy plate.

  Electrical and electronic equipment, automobiles, etc. have built-in parts for conducting electricity or heat, such as terminals, connectors, switches, sockets, relays, bus bars, lead frames, heat sinks, etc. These parts are made of copper alloy. It is used. Here, electrical conductivity and thermal conductivity are in a proportional relationship.

  In recent years, with the miniaturization of electronic components, it is required to increase the bending deflection coefficient. If the connector or the like is downsized, it becomes difficult to increase the displacement of the leaf spring. For this reason, it is necessary to obtain a high contact force with a small displacement, and a higher bending deflection coefficient is required.

  Further, when the bending deflection coefficient is high, the spring back during bending becomes small, and press molding becomes easy. This advantage is particularly great in a high-current connector or the like in which a thick material is used.

  Furthermore, although the heat dissipation component called a liquid crystal frame is used for the liquid crystal of a smart phone or a tablet PC, a higher bending deflection coefficient is required even in such a copper alloy plate for heat dissipation. This is because when the bending deflection coefficient is increased, deformation of the heat sink when an external force is applied is reduced, and the protection against liquid crystal components, IC chips and the like disposed around the heat sink is improved.

  Here, the leaf spring portion of the connector or the like is usually collected in a direction in which the longitudinal direction is orthogonal to the rolling direction (the bending axis at the time of bending deformation is parallel to the rolling direction). Hereinafter, this direction is referred to as a plate width direction (TD). Therefore, an increase in the bending deflection coefficient is particularly important in TD.

  On the other hand, with the miniaturization of electronic components, the cross-sectional area of the copper alloy in the current-carrying part tends to be small. When the cross-sectional area becomes small, heat generation from the copper alloy when energized increases. In addition, electronic parts used in fast-growing electric vehicles and hybrid electric vehicles include parts through which a remarkably high current flows, such as a connector of a battery unit, and heat generation of a copper alloy during energization is a problem. When the heat generation becomes excessive, the copper alloy is exposed to a high temperature environment.

  In an electrical contact of an electronic component such as a connector, a deflection is given to the copper alloy plate, and a contact force at the contact is obtained by a stress generated by the deflection. When a bent copper alloy is held at a high temperature for a long time, the stress, that is, the contact force is lowered due to the stress relaxation phenomenon, and the contact electric resistance is increased. In order to cope with this problem, the copper alloy is required to be more excellent in conductivity so that the amount of heat generation is reduced, and is also required to be superior in stress relaxation characteristics so that the contact force does not decrease even if heat is generated. Similarly, a copper alloy plate for heat dissipation is also desired to have excellent stress relaxation characteristics from the viewpoint of suppressing creep deformation of the heat dissipation plate due to external force.

  It is known that when Zr or Ti is added to Cu, the stress relaxation characteristics are improved (see, for example, Patent Documents 1 and 2). Examples of materials having high electrical conductivity and relatively high strength and good stress relaxation characteristics include C15100 (0.1 mass% Zr-residual Cu), C15150 (0.02 mass% Zr-residual Cu), C18140 (0 .1 mass% Zr-0.3 mass% Cr-0.02 mass% Si-residual Cu), C18145 (0.1 mass% Zr-0.2 mass% Cr-0.2 mass% Zn-residual Cu) C18070 (0.1 mass% Ti-0.3 mass% Cr-0.02 mass% Si-residual Cu), C18080 (0.06 mass% Ti-0.5 mass% Cr-0.1 mass% Ag) Alloys such as -0.08 mass% Fe-0.06 mass% Si-residual Cu) are registered in CDA (Copper Development Association).

JP 2012-180593 A JP 2011-1117055 A

  However, a copper alloy in which Zr or Ti is added to Cu (hereinafter referred to as a Cu-Zr-Ti alloy) has high conductivity and strength, but its bending deflection coefficient of TD is used for parts that carry a large current. Or it was not the level which can be satisfied as a use of the part which dissipates a large amount of heat. Moreover, although it has a comparatively good stress relaxation characteristic, the level of the stress relaxation characteristic is not necessarily sufficient as a use of a component that conducts a large current or a use of a component that dissipates a large amount of heat. In particular, a Cu—Zr—Ti alloy having both a high bending deflection coefficient and excellent stress relaxation properties has not been reported so far.

  For example, in Patent Document 1, in a Cu—Zr—Ti-based alloy, the bending rate of TD is adjusted by adjusting the area ratio of a crystal whose normal line of (111) plane is 20 degrees or less to more than 50%. The deflection coefficient has been improved. However, according to the example, the stress relaxation rate after holding for 1000 hours at 150 ° C. of the alloy whose bending deflection coefficient is improved by this method is 16.9 to 47.2%, which is not a sufficient level. Further, in Patent Document 1, a special process called second type high temperature rolling is added after normal hot rolling for controlling crystal orientation, which leads to a significant increase in manufacturing cost.

  Moreover, while adding 0.05-0.3 mass% Zr, the copper alloy plate which patent document 2 discloses is out of Mg, Ti, Zn, Ga, Y, Nb, Mo, Ag, In, Sn The stress relaxation characteristics are improved by adding one or more of 0.01 to 0.3% by mass and adjusting the crystal grain size after intermediate annealing to 20 to 100 μm. Thus, the stress relaxation rate after holding for 1000 hours is 17.2 to 18.6%, which cannot be said to be sufficiently improved. In the invention, improvement of the bending deflection coefficient is not studied.

  Therefore, an object of the present invention is to provide a copper alloy plate having high strength, high conductivity, a high bending deflection coefficient, and excellent stress relaxation characteristics, and an electronic component suitable for large current use or heat radiation use.

 As a result of intensive studies, the present inventors have determined that the bending deflection coefficient of TD is reduced by controlling the area ratio of the (122) plane and (133) plane in the cross section orthogonal to TD for the Cu—Zr—Ti alloy. I found it to improve. Furthermore, in addition to this crystal orientation control, it has also been found that the stress relaxation characteristic is remarkably improved by adjusting the spring limit value of TD to an appropriate range.

  The present invention completed on the basis of the above knowledge, in one aspect, contains one or two of Zr and Ti in a total of 0.01 to 0.50 mass%, the balance consists of copper and inevitable impurities, When the EBSD measurement is performed in a cross section perpendicular to the plate width direction (hereinafter referred to as “TD”) of the rolled material, the area ratio of the crystal whose angle formed by the normal line of the (122) plane and TD is 10 degrees or less The total of the (133) plane normal and the area ratio of the crystal whose angle formed with TD is 10 degrees or less is 10% or more, and is a copper alloy plate having a tensile strength of 350 MPa or more.

  In another aspect of the present invention, one or two of Zr and Ti are contained in a total amount of 0.01 to 0.50% by mass, and Ag, Fe, Co, Ni, Cr, Mn, Zn, Mg , Si, P, Sn and B are contained in an amount of 1.0% by mass or less, and the balance is made of copper and inevitable impurities, and is orthogonal to the plate width direction (hereinafter referred to as “TD”) of the rolled material. When the EBSD measurement is performed on the cross section, the area ratio of the crystal where the angle formed by the (122) plane normal to TD is 10 degrees or less, and the angle formed by the (133) plane normal to TD is 10 degrees or less. This is a copper alloy plate having a total area ratio of 10% or more and a tensile strength of 350 MPa or more.

  In one embodiment of the copper alloy plate according to the present invention, the spring limit value of TD is adjusted to 200 MPa or more.

  In another embodiment, the copper alloy plate according to the present invention has a conductivity of 70% IACS or more and a TD bending deflection coefficient of 115 GPa or more.

  In another embodiment, the copper alloy plate according to the present invention has a conductivity of 70% IACS or more, a bending deflection coefficient of TD of 115 GPa or more, and a stress relaxation rate of TD after holding at 150 ° C. for 1000 hours. Is 15% or less.

  Another aspect of the present invention is an electronic component for large current using the copper alloy plate.

  In another aspect, the present invention is a heat dissipating electronic component using the copper alloy plate.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the copper alloy board which has high intensity | strength, high electroconductivity, a high bending deflection coefficient, and the outstanding stress relaxation characteristic, and an electronic component suitable for a large current use or a heat dissipation use. This copper alloy can be suitably used as a material for electronic parts such as terminals, connectors, switches, sockets, relays, bus bars, lead frames, etc., and particularly dissipates the material or the large amount of heat of electronic parts that carry a large current. Useful as a material for electronic components.

It is a figure explaining the measurement principle of a stress relaxation rate. It is a figure explaining the measurement principle of a stress relaxation rate.

The present invention will be described below.
(Target characteristics)
The Cu—Zr—Ti alloy plate according to the embodiment of the present invention has a conductivity of 70% IACS or more and a tensile strength of 350 MPa or more. If the electrical conductivity is 70% IACS or higher, it can be said that the amount of heat generated during energization is equivalent to that of pure copper. Further, if the tensile strength is 350 MPa or more, it can be said that the material has a strength necessary for a material for a component that conducts a large current or a material for a component that dissipates a large amount of heat.

  The bending deflection coefficient of TD of the Cu—Zr—Ti alloy plate according to the embodiment of the present invention is 115 GPa or more, more preferably 120 GPa or more. The spring deflection coefficient is a value calculated from the amount of deflection at the time when a load is applied to the cantilever beam within a range not exceeding the elastic limit. As an index of the elastic coefficient, there is a Young's modulus obtained by a tensile test, but the spring deflection coefficient shows a better correlation with the contact force at a leaf spring contact such as a connector. The bending deflection coefficient of TD of a conventional Cu-Zr-Ti alloy plate is about 110 GPa, and by adjusting this to 115 GPa or more, more preferably 120 GPa or more, the contact force is clearly improved after being processed into a connector or the like. In addition, after being processed into a heat radiating plate or the like, it becomes clearly difficult to elastically deform against external force.

  Regarding the stress relaxation characteristics of the Cu-Zr-Ti alloy plate according to the embodiment of the present invention, the stress of TD when 80% stress of 0.2% proof stress is added to TD and held at 150 ° C. for 1000 hours. The relaxation rate (hereinafter simply referred to as stress relaxation rate) is 15% or less, more preferably 10% or less. The stress relaxation rate of the conventional Cu-Zr-Ti-based alloy plate is about 25 to 35%. By making this 15% or less, even if a large current is applied after processing the connector, the contact force decreases. Increase in contact electrical resistance is unlikely to occur, and creep deformation is unlikely to occur even if heat and external force are applied simultaneously after processing into a heat sink.

(Alloy component concentration)
In the Cu—Zr—Ti based alloy plate according to the embodiment of the present invention, a total of one or two of Zr and Ti is 0.01 to 0.50% by mass, more preferably 0.02 to 0.0. Contains 20% by mass. When the total of one or two of Zr and Ti is less than 0.01% by mass, it becomes difficult to obtain a tensile strength of 350 MPa or more and a stress relaxation rate of 15% or less. If the total of one or two of Zr and Ti exceeds 0.5% by mass, it becomes difficult to produce an alloy due to hot rolling cracks or the like. When adding Zr, it is preferable to adjust the addition amount to 0.01 to 0.45 mass%, and when adding Ti, the addition amount is adjusted to 0.01 to 0.20 mass%. It is preferable. When the addition amount is less than the lower limit value, it is difficult to obtain the effect of improving the stress relaxation characteristics, and when the addition amount exceeds the upper limit value, conductivity and manufacturability may be deteriorated.

  Cu-Zr-Ti alloy contains at least one of Ag, Fe, Co, Ni, Cr, Mn, Zn, Mg, Si, P, Sn and B in order to improve strength and heat resistance. Can be made. However, if the amount added is too large, the electrical conductivity may be reduced to be less than 70% IACS, or the manufacturability of the alloy may be deteriorated. Therefore, the amount added is preferably 1.0% by mass or less in total. Is 0.5 mass% or less. Moreover, in order to acquire the effect by addition, it is preferable to make addition amount 0.001 mass% or more in total amount.

(Crystal orientation)
The copper alloy plate according to the embodiment of the present invention has an area ratio of a crystal whose angle of (122) plane normal to TD is 10 degrees or less and an angle of (133) plane normal to TD. The total area ratio (hereinafter referred to as A value) with the area ratio of the crystal of 10 degrees or less is adjusted to 10% or more, more preferably 15% or more.
The A value is determined by an EBSD (Electron Back Scatter Diffraction) method in a cross section orthogonal to the TD of the rolled material. Here, EBSD is a technique for analyzing crystal orientation by using reflected electron Kikuchi diffraction (Kikuchi pattern) generated when a sample is irradiated with an electron beam in a scanning electron microscope (SEM).
When the A value is adjusted to 10% or more, the bending deflection coefficient of TD becomes 115 GPa or more, and at the same time, the stress relaxation characteristics are improved. The upper limit value of the A value is not limited in terms of the bending deflection coefficient of the TD, but the A value often takes a value of 60% or less.

(Spring limit value)
The TD spring limit value of the copper alloy plate is preferably adjusted to 200 MPa or more, and more preferably adjusted to 230 MPa or more. In addition to adjusting the A value to 10% or more, the stress relaxation rate becomes 15% or less by adjusting the TD spring limit value to 200 MPa or more.

(Thickness)
The thickness of the product is preferably 0.1 to 2.0 mm. If the thickness is too thin, the cross-sectional area of the current-carrying part will decrease and heat generation will increase during energization, making it unsuitable as a material for connectors that carry large currents, and because it will deform with a slight external force, It is also unsuitable as a material. On the other hand, if the thickness is too thick, bending becomes difficult. From such a viewpoint, a more preferable thickness is 0.2 to 1.5 mm. When the thickness is in the above range, the bending workability can be improved while suppressing heat generation during energization.

(Use)
The copper alloy plate according to the embodiment of the present invention can be suitably used for applications of electronic components such as terminals, connectors, relays, switches, sockets, bus bars, lead frames, heat sinks, etc. used in electric and electronic equipment. In particular, it is useful for applications of high current electronic components such as connectors and terminals for high current used in electric vehicles, hybrid vehicles, etc., or for heat dissipation electronic components such as liquid crystal frames used in smartphones and tablet PCs. is there.

(Production method)
After dissolving electrolytic copper or the like as a pure copper raw material and reducing the oxygen concentration by carbon deoxidation or the like, one or two of Zr and Ti, and other alloy elements are added as necessary, and the thickness is 30 to 300 mm. Cast into a moderate ingot. After this ingot is made into a plate having a thickness of about 3 to 30 mm by hot rolling, cold rolling and recrystallization annealing are repeated to finish to a predetermined product thickness by final cold rolling, and finally strain relief annealing is performed.
The method of adjusting the A value to 10% or less is not limited to a specific method, but can be achieved by controlling hot rolling conditions, for example. In the hot rolling of the present invention, the material is repeatedly passed through a pair of rolling rolls through an ingot heated to 850 to 1000 ° C., and finished to a target plate thickness. The degree of processing per pass affects the A value. Here, the processing degree R (%) per pass is a sheet thickness reduction rate when the rolling roll passes once, and R = (T ₀ −T) / T ₀ × 100 (T ₀ : rolling) Thickness before passing through roll, T: Thickness after passing through rolling roll).
Regarding R, it is preferable that the maximum value (Rmax) of all paths is 25% or less and the average value (Rave) of all paths is 20% or less. By satisfying both of these conditions, the A value becomes 10% or more. More preferably, Rave is set to 19% or less.

  In recrystallization annealing, part or all of the rolling structure is recrystallized. Further, by annealing under appropriate conditions, Zr, Ti, etc. are precipitated, and the electrical conductivity of the alloy is increased. In the recrystallization annealing before the final cold rolling, the average crystal grain size of the copper alloy sheet is adjusted to 50 μm or less. When the average crystal grain size is too large, it becomes difficult to adjust the tensile strength of the product to 350 MPa or more.

  The conditions for recrystallization annealing before the final cold rolling are determined based on the target crystal grain size after annealing and the target product conductivity. Specifically, annealing may be performed by using a batch furnace or a continuous annealing furnace and setting the furnace temperature to 250 to 800 ° C. In a batch furnace, the heating time may be appropriately adjusted within the range of 30 minutes to 30 hours at a furnace temperature of 250 to 600 ° C. In a continuous annealing furnace, the heating time may be appropriately adjusted within a range of 5 seconds to 10 minutes at a furnace temperature of 450 to 800 ° C. Generally, when annealing is performed at a lower temperature for a longer time, higher conductivity can be obtained with the same crystal grain size.

In the final cold rolling, the material is repeatedly passed between a pair of rolling rolls to finish the target plate thickness. The degree of work of the final cold rolling is preferably 25 to 99%. Here, the working degree r (%) is given by r = (t ₀ −t) / t ₀ × 100 (t ₀ : plate thickness before rolling, t: plate thickness after rolling). If r is too small, it becomes difficult to adjust the tensile strength to 350 MPa or more. If r is too large, the edge of the rolled material may be broken.

  In addition to the adjustment of the A value by controlling the hot rolling conditions, the stress relaxation rate is 15% or less by adjusting the spring limit value of the TD of the product to 200 MPa or more. The method for adjusting the spring limit value to 200 MPa or more is not limited to a specific method, but it can be performed, for example, by performing strain relief annealing under appropriate conditions after the final rolling.

  That is, the spring limit value is adjusted by adjusting the tensile strength after strain relief annealing to a value that is 10 to 100 MPa lower, preferably 20 to 80 MPa lower than the tensile strength before strain relief annealing (after final rolling). 200 MPa or more. If the amount of decrease in tensile strength is too small, it becomes difficult to adjust the spring limit value to 200 MPa or more. If the decrease in tensile strength is too large, the tensile strength of the product may be less than 350 MPa.

  Specifically, when a batch furnace is used, the heating time is appropriately adjusted in the range of 30 minutes to 30 hours at a furnace temperature of 100 to 500 ° C., and when a continuous annealing furnace is used, 300 to 700 ° C. What is necessary is just to adjust the fall amount of tensile strength to the said range by adjusting a heating time suitably in the range for 5 second to 10 minutes in the furnace temperature of this.

  Examples of the present invention will be described below together with comparative examples, but these examples are provided for better understanding of the present invention and its advantages, and are not intended to limit the invention.

  After adding the alloy element to the molten copper, it was cast into an ingot having a thickness of 200 mm. The ingot was heated at 950 ° C. for 3 hours and formed into a plate having a thickness of 15 mm by hot rolling. After grinding and removing the oxide scale on the surface of the plate after hot rolling, annealing and cold rolling were repeated and finished to a predetermined product thickness by final cold rolling. Finally, strain relief annealing was performed.

  In hot rolling, the maximum value (Rmax) and average value (Rave) of the degree of processing per pass were variously changed.

For annealing before final cold rolling (final recrystallization annealing), a batch furnace is used, the heating time is 5 hours, the furnace temperature is adjusted in the range of 250 to 700 ° C, and the crystal grain size and conductivity after annealing are adjusted. Changed.
In the final cold rolling, the degree of work (r) was varied. In strain relief annealing, a continuous annealing furnace was used, the furnace temperature was 500 ° C., the heating time was adjusted between 1 second and 10 minutes, and the amount of decrease in tensile strength was variously changed. In some examples, strain relief annealing was not performed.

The following measurements were performed for materials in the process of manufacture and materials (products) after strain relief annealing.
(component)
The alloy element concentration of the material after strain relief annealing was analyzed by ICP-mass spectrometry.

(Average grain size after final recrystallization annealing)
After the cross section perpendicular to the rolling direction was finished to a mirror surface by mechanical polishing, crystal grain boundaries were revealed by etching. On this metal structure, the average crystal grain size was determined by measurement according to the cutting method of JIS H 0501 (1999).

(Crystal orientation of the product)
An EBSD measurement was performed by irradiating an electron beam to a cross section perpendicular to TD (cross section parallel to the thickness direction and the rolling direction). The measurement area was 0.1 mm ^2, and scanning was performed in 2 μm steps to analyze the orientation. Then, an area ratio of the crystal whose angle formed by the normal of the (122) plane and TD is 10 degrees or less and an area ratio of the crystal whose angle formed by the normal of the (133) plane and TD are 10 degrees or less are obtained, The total (A value) of both area ratios was calculated. Further, the area ratio of a crystal having an angle formed by the normal of the (111) plane and TD being 10 degrees or less was also obtained.

(Tensile strength)
For the material after the final cold rolling and strain relief annealing, sample No. 13B specified in JIS Z2241 was taken so that the tensile direction was parallel to the rolling direction, and pulled in parallel with the rolling direction in accordance with JIS Z2241. A test was conducted to determine the tensile strength.

(Spring limit value)
A strip-shaped specimen having a width of 10 mm was taken from the material after strain relief annealing so that the longitudinal direction of the specimen was perpendicular to the rolling direction, and a TD spring was obtained by a moment type test specified in JIS H3130. The limit value was measured.

(conductivity)
A test piece was taken from the material after strain relief annealing so that the longitudinal direction of the test piece was parallel to the rolling direction, and the conductivity at 20 ° C. was measured by a four-terminal method in accordance with JIS H0505.

(Bending deflection coefficient)
The bending deflection coefficient of TD was measured according to the Japan Copper and Brass Association (JACBA) technical standard “Method of measuring bending deflection coefficient by cantilever of copper and copper alloy strip”.
A strip-shaped test piece having a thickness t and a width w (= 10 mm) was taken so that the longitudinal direction of the test piece was orthogonal to the rolling direction. One end of this sample was fixed, a load of P (= 0.15 N) was applied to a position L (= 100 t) from the fixed end, and a bending deflection coefficient B was obtained from the deflection d at this time using the following equation.
B = 4 · P · (L / t) ³ / (w · d)

(Stress relaxation rate)
A strip-shaped test piece having a width of 10 mm and a length of 100 mm was collected from the material after strain relief annealing so that the longitudinal direction of the test piece was orthogonal to the rolling direction. As in FIG. 1, stress as a working point position of the l = 50 mm, giving a deflection of y ₀ on the test piece, corresponding to 80% of the 0.2% yield strength of TD (measured in accordance with J IS Z2241) (S) was loaded. y ₀ was determined by the following equation.
y ₀ = (2/3) · l ² · s / (E · t)
Here, E is the bending deflection coefficient of TD, and t is the thickness of the sample. Unloading after heating at 150 ° C. for 1000 hours, and measuring the amount of permanent deformation (height) y as shown in FIG. 2, stress relaxation rate {[y (mm) / y ₀ (mm)] × 100 (%) } Was calculated.

  Table 1 shows the evaluation results. The notation of “<10 μm” in the crystal grain size after the final recrystallization annealing in Table 1 indicates that when all of the rolling structure is recrystallized and the average crystal grain size is less than 10 μm, and only a part of the rolling structure is used. Both cases of recrystallization are included.

  Table 2 shows examples of Invention Example 1, Invention Example 4, Comparative Example 1, and Comparative Example 3 in Table 1 as the finished thickness of the material in each pass of hot rolling and the degree of processing per pass.

  In the copper alloy sheets of Invention Examples 1 to 25, the total concentration of Zr and Ti is adjusted to 0.01 to 0.50 mass%, Rmax is 25% or less and Rave is 20% or less in hot rolling, The crystal grain size was adjusted to 50 μm or less in the crystal annealing, and the workability was set to 25 to 99% in the final cold rolling. As a result, the A value was 10% or more, and a conductivity of 70% IACS or more, a tensile strength of 350 MPa or more, and a bending deflection coefficient of 115 GPa or more were obtained.

  Further, in Examples 1 to 22, since the tensile strength was reduced by 10 to 100 MPa in the strain relief annealing after the final rolling, the spring limit value was 200 MPa or more, and as a result, a stress relaxation rate of 15% or less was also obtained.

  On the other hand, in Examples 23 and 24, the amount of decrease in tensile strength in strain relief annealing was less than 10 MPa, and in Example 25, strain relief annealing was not performed, so the spring limit was less than 200 MPa, resulting in stress. The relaxation rate exceeded 15%.

  In Comparative Examples 1 to 5, Rmax or Rave deviated from the definition of the present invention, so the A value was less than 10%. As a result, the bending deflection coefficient was less than 115 GPa. Furthermore, although the spring limit value was adjusted to 200 MPa or more by performing strain relief annealing under the condition of reducing the tensile strength by 10 to 100 MPa, the stress relaxation rate exceeded 15%.

  In Comparative Example 6, since the total concentration of Zr and Ti was less than 0.01% by mass, the tensile strength after strain relief annealing was less than 350 MPa, and the stress relaxation rate exceeded 15%.

  In Comparative Example 7, the degree of work in final cold rolling was less than 25%, and in Comparative Example 8, the crystal grain size after recrystallization annealing before final cold rolling exceeded 50 μm. The tensile strength was less than 350 MPa.

  In Comparative Example 9, the ingot was processed to a thickness of 15 mm according to the process disclosed in Patent Document 1. A 200 mm thick ingot heated at 950 ° C. for 3 hours (homogenization heat treatment) is rolled to a thickness of 100 mm at a processing temperature of 700 to 1000 ° C. (first type high temperature rolling, processing degree 50%), and then 5 to 5 mm. Cooled to room temperature at 100 ° C./second. Then, it reheated to 550 degreeC and rolled to thickness 15mm at the processing temperature of 400-550 degreeC (2nd type high temperature rolling, workability 70%). Here, Rmax and Rave in Table 1 are those during the first type high temperature rolling. In addition, the process after thickness 15mm was performed similarly to the other Example. As a result, the (111) plane increased in the cross section orthogonal to the TD, and the area ratio of the crystal whose angle between the normal line of the (111) plane and the TD was 10 degrees or less exceeded 50%. And the bending deflection coefficient became 115 GPa or more. However, the stress relaxation rate exceeded 15% even though the spring limit value was adjusted to 200 MPa or more by performing strain relief annealing under conditions where the tensile strength was reduced by 10 to 100 MPa.

Claims (7)

  One or two of Zr and Ti are contained in a total of 0.01 to 0.50 mass%, the balance is made of copper and inevitable impurities, and the sheet width direction of the rolled material (hereinafter referred to as “TD”) When the EBSD measurement is performed on an orthogonal cross section, the area ratio of the crystal where the angle formed by the (122) plane normal to TD is 10 degrees or less, and the angle formed by the (133) plane normal to TD is 10 A copper alloy sheet having a tensile strength of 350 MPa or more, with a total of 10% or more of the area ratio of the crystals having a degree of less than or equal to the degree.   One or two of Zr and Ti are contained in a total of 0.01 to 0.50% by mass, and further Ag, Fe, Co, Ni, Cr, Mn, Zn, Mg, Si, P, Sn, and B When one or more of them are contained in an amount of 1.0% by mass or less, the balance is made of copper and inevitable impurities, and EBSD measurement is performed in a cross section perpendicular to the plate width direction of the rolled material (hereinafter referred to as “TD”). The area ratio of the crystal whose angle between the normal line of (122) plane and TD is 10 degrees or less, and the area ratio of the crystal whose angle between the normal line of (133) plane and TD is 10 degrees or less Is a copper alloy sheet characterized by having a tensile strength of 350 MPa or more.   The copper alloy sheet according to claim 1 or 2, wherein a spring limit value of TD is adjusted to 200 MPa or more.   The copper alloy sheet according to claim 1 or 2, wherein the conductivity is 70% IACS or more, and the bending deflection coefficient of TD is 115GPa or more.   The electrical conductivity is 70% IACS or more, the bending deflection coefficient of TD is 115 GPa or more, and the stress relaxation rate of TD after holding at 150 ° C. for 1000 hours is 15% or less. The copper alloy plate as described.   The electronic component for large currents using the copper alloy plate of any one of Claims 1-5.   The electronic component for heat dissipation using the copper alloy plate of any one of Claims 1-5.

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