JP2015086462A - Copper alloy sheet excellent in conductivity and stress relaxation property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper alloy sheet having high strength, high conductivity and excellent stress relaxation property, a manufacturing method of the copper alloy sheet and an electronic component for large current and an electronic component for heat release using the copper alloy sheet.SOLUTION: There is provided a copper alloy sheet containing one or more kind of Ag, B, Co, Cr, Fe, Mg, Mn, Ni, P, Si, Sn, Ti, Zn nd Zr of total 0 to 20 mass% and the balance copper with its inevitable impurities, and having 30%IACS or more of conductivity and 290 MPa or more of 0.2% yield strength, and thermal shrinkage rate in a rolling direction by heating for 30 minutes at 200°C of 50 ppm or less.

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 raw material, a manufacturing method thereof, and an electronic component using the copper alloy plate. Among these, copper alloys suitable for use in high current electronic parts such as high current connectors and terminals used in electric vehicles, hybrid cars, etc., or in heat dissipation electronic parts such as liquid crystal frames used in smartphones and tablet PCs. The present invention relates to a plate, a manufacturing method thereof, 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, 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 such as a connector, the copper alloy plate is deflected, 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.

  On the other hand, for example, a heat radiating component called a liquid crystal frame is used for a liquid crystal of a smartphone or a tablet PC. Even in such a copper alloy plate for heat dissipation, when stress relaxation characteristics are enhanced, creep deformation of the heat sink due to external force is suppressed, and the protection against liquid crystal components, IC chips, etc. disposed around the heat sink is improved. , Etc. can be expected. For this reason, it is desired that the copper alloy plate for heat dissipation also has excellent stress relaxation characteristics.

  For example, Japanese Patent Application Laid-Open No. 2012-177197 discloses a copper alloy in which the Cube orientation is developed and has relatively good stress relaxation characteristics. (Patent Document 1).

JP 2012-177197 A

  However, when improving the characteristics of a copper alloy by controlling the crystal orientation, unnecessary characteristic changes such as a decrease in Young's modulus often occur simultaneously. In the manufacturing process, it is necessary to add special heat treatment and processing, and the manufacturing cost often increases.

  Therefore, it can be said that it is extremely significant industrially if the stress relaxation characteristics of the copper alloy can be improved by adjusting the minor manufacturing process without depending on the control of the crystal orientation.

  Then, an object of this invention is to provide the copper alloy board which has high intensity | strength, high electroconductivity, and the outstanding stress relaxation characteristic. Furthermore, it aims at providing the electronic component suitable for the manufacturing method of this copper alloy plate, and a large current use or a heat dissipation use.

  As a result of intensive studies, the present inventors have found that the stress relaxation characteristics of the copper alloy sheet are improved by adjusting the thermal expansion / contraction rate in the rolling parallel direction of the copper alloy sheet to a predetermined value.

  The present invention completed on the basis of the above knowledge is, in one aspect, a total of one or more of Ag, B, Co, Cr, Fe, Mg, Mn, Ni, P, Si, Sn, Ti, Zn, and Zr. The rolling direction when it is heated at 200 ° C. for 30 minutes, containing 0 to 20% by mass, the balance being copper and its inevitable impurities, having a conductivity of 30% IACS or higher and a 0.2% proof stress of 290 MPa or higher. This is a copper alloy plate having a thermal expansion / contraction rate of 50 ppm or less.

  In another embodiment, the copper alloy plate according to the present invention contains 0.005 to 1% by mass in total of one or more of Ag, P, Sn, Fe and Ni, and the balance is made of copper and its inevitable impurities. , 80-102% IACS conductivity.

  In another embodiment, the copper alloy plate according to the present invention is 0.1 to 0.5% by mass of Cr, 0.1 to 0.5% by mass of Sn, and 0.1 to 0.5% by mass of Zn. %, Ag, B, Co, Fe, Mg, Mn, Ni, P, Si, Ti and Zr are contained in a total of 0 to 0.2% by mass, with the balance being made of copper and its inevitable impurities And has a conductivity of 70-90% IACS.

  In another embodiment, the copper alloy plate according to the present invention is 1 to 3% by mass of Fe, 0.01 to 0.2% by mass of P, 0.05 to 0.5% by mass of Zn, Ag, B, Co, Cr, Mg, Mn, Ni, Si, Sn, Ti and Zr are contained in a total of 0 to 0.2% by mass, with the balance being copper and its inevitable impurities, It has a conductivity of 80% IACS.

  In still another embodiment, the copper alloy plate according to the present invention is 0.5 to 3% by mass of Ni, 0.2 to 2% by mass of Sn, 0.02 to 0.2% by mass of P, Ag, B, Co, Cr, Fe, Mg, Mn, Si, Ti, Zn and Zr are contained in a total of 0 to 0.2% by mass, with the balance consisting of copper and its inevitable impurities, 30 to It has a conductivity of 60% IACS.

  In yet another embodiment, the copper alloy plate according to the present invention is 0.2 to 1% by mass of Mg, 0.001 to 0.1% by mass of P, Ag, B, Co, Cr, Fe, Mn, One or more of Ni, Si, Sn, Ti, Zn and Zr are contained in a total amount of 0 to 0.2% by mass, the balance is made of copper and its inevitable impurities, and has a conductivity of 50 to 70% IACS. .

  In yet another embodiment, the copper alloy plate according to the present invention is 0.1 to 5% by mass of Ni, 0.01 to 0.3% by mass of P, 0.01 to 0.3% by mass of Fe, Containing at least one of Ag, B, Co, Cr, Mg, Mn, Si, Sn, Ti, Zn and Zr in a total amount of 0 to 0.2% by mass, with the balance consisting of copper and its inevitable impurities, It has a conductivity of 50-90% IACS.

  In yet another embodiment, the copper alloy sheet according to the present invention has a stress relaxation rate of 30% or less after being held at 150 ° C. for 1000 hours.

In yet another embodiment, the copper alloy sheet according to the present invention is, after hot rolling the ingot at 800 to 1000 ° C. to a thickness of 3 to 30 mm, repeating cold rolling and recrystallization annealing to obtain the final cold A method for producing a copper alloy sheet that is subjected to strain relief annealing after rolling,
(A) In the recrystallization annealing before the final cold rolling, the furnace temperature is 250 to 800 ° C., the average crystal grain size of the copper alloy plate is adjusted to 50 μm or less,
(B) In the final cold rolling, the total workability is 25 to 99%, the rolling work per pass is 20% or less,
(C) In the strain relief annealing, using a continuous annealing furnace, the furnace temperature is 300 to 700 ° C., the tension applied to the copper alloy sheet in the furnace is 1 to 5 MPa, and the copper alloy sheet is passed through, 0 .2% yield strength is reduced by 10-50 MPa,
Including that.

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

  In another aspect of the present invention, there is provided 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, and the outstanding stress relaxation characteristic, its manufacturing method, and an electronic component suitable for a large current use or a heat dissipation use. This copper alloy plate can be suitably used as a material for electronic parts such as terminals, connectors, switches, sockets, relays, bus bars, lead frames, heat sinks, etc. It is useful as a material for electronic parts that dissipate heat.

It is a top view which shows the test piece used for the measurement of the thermal expansion-contraction rate in the Example. It is a figure explaining the measurement principle of the stress relaxation rate of an Example. It is a figure explaining the measurement principle of the stress relaxation rate of an Example.

The present invention will be described below.
(Target characteristics)
The copper alloy plate according to the embodiment of the present invention has a conductivity of 30% IACS or more and a 0.2% proof stress of 290 MPa or more. If the electrical conductivity is 30% IACS or higher, the amount of heat generated during energization is suppressed. Further, if the 0.2% proof stress is 290 MPa or more, it can be said that the material has the strength required as a material for parts that conduct a large current or a material for parts that dissipate a large amount of heat.

  Regarding the stress relaxation characteristics of the copper alloy plate according to the embodiment of the present invention, the stress relaxation rate of the copper alloy plate (hereinafter referred to as “80% stress of 0.2% proof stress”) is maintained at 150 ° C. for 1000 hours. , Simply referred to as stress relaxation rate) is 30% or less, more preferably 25% or less, and still more preferably 20% or less. By reducing the stress relaxation rate to 30% or less, even if a large current is applied after being processed into a connector, it is difficult for the contact electric resistance to increase due to a decrease in contact force. Creep deformation is unlikely to occur even when is added simultaneously.

(Alloy component concentration)
The effects of the present invention include one or more of Ag, B, Co, Cr, Fe, Mg, Mn, Ni, P, Si, Sn, Ti, Zn and Zr in a total amount of 0 to 20% by mass, The balance is satisfactorily exhibited in a copper alloy composed of copper and its inevitable impurities, and particularly high effects are exhibited in, for example, the following A to F copper alloys.

(Alloy A)
It is a copper alloy containing 0.005 to 1% by mass in total of one or more of Ag, P, Sn, Fe and Ni, with the balance being copper and its inevitable impurities. The conductivity of this copper alloy is 80 to 102% IACS. A more preferred component is a copper alloy containing 0.01 to 0.2% by mass in total of one or more of Ag, P, Sn, Fe and Ni, with the balance being copper and unavoidable impurities thereof. The conductivity is 83-97% IACS.

(Alloy B)
Cr is 0.1 to 0.5% by mass, Sn is 0.1 to 0.5% by mass, Zn is 0.1 to 0.5% by mass, Ag, B, Co, Fe, Mg, Mn, Ni, It is a copper alloy containing at least one of P, Si, Ti and Zr in a total of 0 to 0.2 mass%, with the balance being copper and its inevitable impurities. The conductivity of this copper alloy is 70-90% IACS. More preferable components are 0.2 to 0.4% by mass of Cr, 0.2 to 0.3% by mass of Sn, 0.2 to 0.3% by mass of Zn, Ag, B, Co, Fe, Mg , Mn, Ni, P, Si, Ti and Zr in a total of 0 to 0.2% by mass, with the balance being copper and its inevitable impurities, a copper alloy, the conductivity of this copper alloy The rate is 70-80% IACS.

(Alloy C)
Fe 1 to 3 mass%, P 0.01 to 0.2 mass%, Zn 0.05 to 0.5 mass%, Ag, B, Co, Cr, Mg, Mn, Ni, Si, Sn, It is a copper alloy containing at least one of Ti and Zr in a total amount of 0 to 0.2 mass%, with the balance being copper and its inevitable impurities. The conductivity of this copper alloy is 60-80% IACS. More preferable components are Fe to 2 to 2.5 mass%, P to 0.02 to 0.15 mass%, Zn to 0.1 to 0.2 mass, Ag, B, Co, Cr, Mg, Mn, One or more of Ni, Si, Sn, Ti and Zr is contained in a total of 0 to 0.2% by mass, and the balance is copper and an inevitable impurity thereof. The copper alloy has a conductivity of 60 ~ 75% IACS.

(Alloy D)
Ni: 0.5-3 mass%, Sn: 0.2-2 mass%, P: 0.02-0.2 mass%, Ag, B, Co, Cr, Fe, Mg, Mn, Si, Ti, It is a copper alloy containing 0 to 0.2 mass% in total of one or more of Zn and Zr. The conductivity of this copper alloy is 30-60% IACS. More preferable component ranges are 0.8 to 1.2% by mass of Ni, 0.4 to 0.6% by mass of Sn, 0.05 to 0.15% by mass of P, Ag, B, Co, Cr, A copper alloy containing at least one of Fe, Mg, Mn, Si, Ti, Zn and Zr in a total amount of 0 to 0.2% by mass, the balance being copper and its inevitable impurities, and Ni of 0.8 -1.2 mass%, Sn 0.8-1.0 mass%, P 0.05-0.15 mass%, Ag, B, Co, Cr, Fe, Mg, Mn, Si, Ti, Zn And one or more of Zr in a total of 0 to 0.2% by mass, the balance being copper alloy consisting of copper and its inevitable impurities, and the conductivity of each copper alloy is 45 to 55% IACS and 35 to 45 % IACS.

(Alloy E)
0.2 to 1% by mass of Mg, 0.001 to 0.1% by mass of P, one or more of Ag, B, Co, Cr, Fe, Mn, Ni, Si, Sn, Ti, Zn and Zr Is a copper alloy containing 0 to 0.2% by mass in total with the balance being copper and its inevitable impurities. The conductivity of this copper alloy is 50-70% IACS. More preferable components are 0.5 to 0.9% by mass of Mg, 0.001 to 0.02% by mass of P, Ag, B, Co, Cr, Fe, Mn, Ni, Si, Sn, Ti, Zn One or more of Zr and Zr are contained in a total of 0 to 0.2% by mass, and the balance is copper and its inevitable impurities. The copper alloy has a conductivity of 50 to 65% IACS.

(Alloy F)
0.1 to 5% by mass of Ni, 0.01 to 0.3% by mass of P, 0.01 to 0.3% by mass of Fe, Ag, B, Co, Cr, Mg, Mn, Si, Sn, It is a copper alloy containing at least one of Ti, Zn, and Zr in a total amount of 0 to 0.2 mass%, with the balance being copper and its inevitable impurities. The conductivity of this copper alloy is 50-90% IACS. More preferable component ranges are 0.5 to 0.9 mass% for Ni, 0.02 to 0.2 mass% for P, 0.05 to 0.15 mass% for Fe, and 0.03 to 0.3 mass for Zn. 2% by mass, Ag, B, Co, Cr, Mg, Mn, Si, Sn, Ti and Zr are contained in a total of 0 to 0.2% by mass, with the balance being made of copper and its inevitable impurities The copper alloy has a conductivity of 60 to 80% IACS.

  As the concentration of the alloy component increases, the electrical conductivity decreases while the tensile strength increases.

(Thermal expansion and contraction rate)
When heat is applied to a copper alloy plate, a very small dimensional change occurs. The ratio of this dimensional change is referred to as the thermal expansion / contraction rate. The present inventors have found that the stress relaxation rate can be remarkably improved by refining the metal structure of the copper alloy sheet using the thermal expansion / contraction rate as an index.

  In the present invention, a dimensional change rate in the rolling direction when heated at 200 ° C. for 30 minutes is used as the thermal expansion / contraction rate. By adjusting the absolute value of this thermal expansion / contraction rate (hereinafter simply referred to as thermal expansion / contraction rate) to 50 ppm or less, preferably 30 ppm or less, the stress relaxation rate becomes 30% or less. The lower limit value of the thermal expansion / contraction rate is not limited in terms of the characteristics of the copper alloy sheet, but the thermal expansion / contraction rate is rarely 1 ppm or less.

  Here, the reason for setting the heating condition at the time of measuring the thermal expansion / contraction rate at 200 ° C. for 30 minutes is that the best correlation was obtained with the stress relaxation characteristics when measured under this condition.

(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, 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 is suitably used for applications of electronic parts such as terminals, connectors, relays, switches, sockets, bus bars, lead frames, heat sinks, etc. used in electric / electronic devices, automobiles, etc. In particular, applications of high-current electronic components such as connectors and terminals for large currents used in electric vehicles, hybrid vehicles, etc., or uses of electronic components for heat dissipation such as liquid crystal frames used in smartphones and tablet PCs Useful for.

(Production method)
Hereinafter, an example of the suitable manufacturing method of the copper alloy plate which concerns on this invention is demonstrated.

  As a pure copper material, electrolytic copper or the like is melted, an alloy element is added, and cast into an ingot having a thickness of about 30 to 300 mm. After this ingot is made into a plate having a thickness of about 3 to 30 mm by hot rolling, 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. Here, the means for adjusting the thermal expansion / contraction ratio to the above range is not limited to a specific method, but for example, it is possible to control both conditions of final cold rolling and strain relief annealing as described later.

  In recrystallization annealing, part or all of the rolling structure is recrystallized. In recrystallization annealing (final recrystallization annealing) before final cold rolling, the average crystal grain size of the copper alloy sheet is adjusted to 50 μm or less. If the average crystal grain size is too large, it is difficult to adjust the 0.2% yield strength to 290 MPa or more.

  The conditions for final recrystallization annealing are determined based on the target crystal grain size after annealing. 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.

In the final cold rolling, the material is repeatedly passed between a pair of rolling rolls to finish the target plate thickness. The total workability of final cold rolling and the workability per pass are controlled.
The total workability R (%) is given by R = (t ₀ −t) / t ₀ × 100 (t ₀ : plate thickness before final cold rolling, t: plate thickness after final cold rolling). Further, 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 roll) Thickness before passing, T: Thickness after passing the rolling roll).
The total processing degree R is preferably 25 to 99%. When R is too small, it becomes difficult to adjust the 0.2% proof stress to 290 MPa or more. When R is too large, the edge of the rolled material may be broken.

  The processing degree r per pass is preferably 20% or less. If at least one of the passes in which r exceeds 20% is included, it is difficult to adjust the thermal expansion / contraction rate to 50 ppm or less even if strain relief annealing is performed under the conditions described later.

  The strain relief annealing of the present invention is performed using a continuous annealing furnace. In the case of a batch furnace, since the material is heated in a state of being wound in a coil shape, the material is deformed during the heating, and the material is warped. Therefore, the batch furnace is not suitable for the strain relief annealing of the present invention.

  In a continuous annealing furnace, the furnace temperature is set to 300 to 700 ° C., the heating time is appropriately adjusted in the range of 5 seconds to 10 minutes, and the 0.2% proof stress after the stress relief annealing is 0.2% before the stress relief annealing. The value is adjusted to a value 10-50 MPa lower than the proof stress, preferably 15-45 MPa lower. Further, the tension applied to the material in the continuous annealing furnace is adjusted to 1 to 5 MPa, more preferably 1 to 4 MPa. By performing strain relief annealing under these conditions, the thermal expansion / contraction rate is reduced.

  If the 0.2% yield strength decrease is too small or too large, the reduction in thermal expansion / contraction due to strain relief annealing becomes insufficient, and it becomes difficult to adjust the thermal expansion / contraction to 50 ppm or less. Moreover, even if tension is too large, reduction of the thermal expansion / contraction rate due to strain relief annealing becomes insufficient, and it becomes difficult to adjust the thermal expansion / contraction rate to 50 ppm or less. On the other hand, if the tension is too small, the material in the passing plate of the annealing furnace may come into contact with the furnace wall, and the surface or edge of the material may be damaged.

  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 hot rolled plate, annealing and cold rolling were repeated, and the product was finished to a predetermined product thickness by the final cold rolling. Finally, strain relief annealing was performed using a continuous annealing furnace.

  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 total workability and the workability per pass were controlled.

  In strain relief annealing using a continuous annealing furnace, the furnace temperature was 500 ° C., the heating time was adjusted between 1 second and 15 minutes, and the amount of 0.2% proof stress reduction due to strain relief annealing was variously changed. In addition, various tensions were added to the material in the furnace.

  The following measurement was performed on the material in the process of manufacturing and the material 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 measuring according to the cutting method of JIS H0501 (1999).

(0.2% yield 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. Tests were performed to determine 0.2% yield strength.

(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.

(Thermal expansion and contraction rate)
A strip-shaped test piece having a width of 20 mm and a length of 210 mm 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 L ₀ (= 200 mm) as shown in FIG. ) Were stamped at two points. Then, it heated at 200 degreeC for 30 minutes, and measured the dent space | interval (L) after a heating. Then, the absolute value of the value calculated by the formula of (L−L ₀ ) / L ₀ × 10 ⁶ was obtained as the thermal expansion / contraction rate (ppm).

(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 parallel to the rolling direction. As shown in FIG. 2, with the position of l = 50 mm as the working point, the test piece was given a deflection of y ₀ and a stress (s) corresponding to 80% of the 0.2% proof stress in the rolling direction was applied. y ₀ was determined by the following equation.
y ₀ = (2/3) · l ² · s / (E · t)
Here, E is the Young's modulus in the rolling direction, and t is the thickness of the sample. After unloading after heating at 150 ° C. for 1000 hours, the amount of permanent deformation (height) y shown in FIG. 3 was measured, and the stress relaxation rate {[y (mm) / y ₀ (mm)] × 100 (%)} Was calculated.

  Tables 1, 2, 3, 4, 5 and 6 are examples relating to Alloy A, Alloy B, Alloy C, Alloy D, Alloy E and Alloy F, respectively. Table 7 shows examples of alloys other than those described in Tables 1-6. In these examples and comparative examples, a plurality of passes were carried out in the final cold rolling, and the maximum value in the working degree of each of these passes is shown. In addition, the expression “<10 μm” in the crystal grain size after the final recrystallization annealing indicates that all of the rolling structure is recrystallized and the average crystal grain size is less than 10 μm, and that only a part of the rolling structure is recrystallized. Both cases of crystallization are included.

  In the copper alloy plates of the inventive examples in Tables 1 to 7, one or more of Ag, B, Co, Cr, Fe, Mg, Mn, Ni, P, Si, Sn, Ti, Zn, and Zr are 0 in total. In the recrystallization annealing before the final cold rolling, the crystal grain size is adjusted to 50 μm or less, and in the final cold rolling, the total workability is 25 to 99%, and processing per pass The degree was adjusted to 20% or less, and in strain relief annealing, the material was passed through a continuous annealing furnace with a tension of 1 to 5 MPa to reduce the 0.2% yield strength by 10 to 50 MPa. As a result, the thermal expansion / contraction rate was 50 ppm or less, and a conductivity of 30% IACS or more, a 0.2% proof stress of 290 MPa or more, and a stress relaxation rate of 30% or less were obtained.

In Comparative Example 1, the strain relief annealing was not performed, the thermal expansion / contraction rate exceeded 50 ppm, and the stress relaxation rate exceeded 30%.
In Comparative Example 2, the amount of decrease in 0.2% yield strength in strain relief annealing was excessively small, and in Comparative Examples 3 and 4, the amount of decrease in 0.2% yield strength in strain relief annealing was excessive. For this reason, the thermal expansion / contraction rate exceeded 50 ppm and the stress relaxation rate exceeded 30%.
In Comparative Examples 5 to 7, although strain relief annealing was performed, the material tension in the furnace exceeded 5 MPa, so the thermal expansion / contraction rate exceeded 50 ppm and the stress relaxation rate exceeded 30%.
In Comparative Examples 8 and 9, since the degree of work per pass in the final cold rolling exceeded 20%, the thermal expansion / contraction rate exceeded 50 ppm and the stress relaxation rate exceeded 30%.

  In Comparative Example 10, the total degree of work in the final cold rolling was less than 25%, and in Comparative Example 11, the crystal grain size after recrystallization annealing before the final cold rolling exceeded 50 μm. The 0.2% proof stress was less than 290 MPa.

Claims (11)

  Ag, B, Co, Cr, Fe, Mg, Mn, Ni, P, Si, Sn, Ti, Zn, and Zr are contained in a total of 0 to 20% by mass, with the balance being copper and its inevitable A copper alloy sheet comprising impurities, having a conductivity of 30% IACS or more and a 0.2% proof stress of 290 MPa or more, and a thermal expansion / contraction ratio in the rolling direction by heating at 200 ° C. for 30 minutes of 50 ppm or less.   One or more of Ag, P, Sn, Fe and Ni are contained in a total amount of 0.005 to 1% by mass, the balance is made of copper and its inevitable impurities, and has a conductivity of 80 to 102% IACS. The copper alloy plate according to claim 1.   Cr is 0.1 to 0.5% by mass, Sn is 0.1 to 0.5% by mass, Zn is 0.1 to 0.5% by mass, Ag, B, Co, Fe, Mg, Mn, Ni, It is characterized by containing at least one of P, Si, Ti and Zr in a total of 0 to 0.2% by mass, the balance being made of copper and its inevitable impurities and having a conductivity of 70 to 90% IACS. The copper alloy plate according to claim 1.   Fe 1 to 3 mass%, P 0.01 to 0.2 mass%, Zn 0.05 to 0.5 mass%, Ag, B, Co, Cr, Mg, Mn, Ni, Si, Sn, The total content of one or more of Ti and Zr is 0 to 0.2% by mass, and the balance is made of copper and its inevitable impurities and has a conductivity of 60 to 80% IACS. The copper alloy plate described in 1.   Ni: 0.5-3 mass%, Sn: 0.2-2 mass%, P: 0.02-0.2 mass%, Ag, B, Co, Cr, Fe, Mg, Mn, Si, Ti, The total content of one or more of Zn and Zr is 0 to 0.2% by mass, and the balance is made of copper and its inevitable impurities and has a conductivity of 30 to 60% IACS. The copper alloy plate described in 1.   0.2 to 1% by mass of Mg, 0.001 to 0.1% by mass of P, one or more of Ag, B, Co, Cr, Fe, Mn, Ni, Si, Sn, Ti, Zn and Zr The copper alloy plate according to claim 1, wherein 0 to 0.2 mass% in total is contained, the balance is made of copper and its inevitable impurities, and has a conductivity of 50 to 70% IACS.   0.1 to 5% by mass of Ni, 0.01 to 0.3% by mass of P, 0.01 to 0.3% by mass of Fe, Ag, B, Co, Cr, Mg, Mn, Si, Sn, One or more of Ti, Zn and Zr are contained in a total amount of 0 to 0.2% by mass, the balance is made of copper and its inevitable impurities, and has a conductivity of 50 to 90% IACS. Item 4. The copper alloy sheet according to Item 1.   The copper alloy plate according to any one of claims 1 to 7, wherein a stress relaxation rate after holding at 150 ° C for 1000 hours is 30% or less. In the method of manufacturing a copper alloy plate, after ingot is hot rolled at 800 to 1000 ° C. to a thickness of 3 to 30 mm, cold rolling and recrystallization annealing are repeated, and after final cold rolling, strain relief annealing is performed. There,
(A) In the recrystallization annealing before the final cold rolling, the furnace temperature is 250 to 800 ° C., the average crystal grain size of the copper alloy plate is adjusted to 50 μm or less,
(B) In the final cold rolling, the total workability is 25 to 99%, the rolling work per pass is 20% or less,
(C) In the strain relief annealing, using a continuous annealing furnace, the furnace temperature is 300 to 700 ° C., the tension applied to the copper alloy sheet in the furnace is 1 to 5 MPa, and the copper alloy sheet is passed through, 0 .2% yield strength is reduced by 10-50 MPa,
The manufacturing method of the copper alloy plate of any one of Claims 1-8 containing this.   The electronic component for large currents using the copper alloy plate of any one of Claims 1-8.   The electronic component for heat dissipation using the copper alloy plate of any one of Claims 1-8.