JP5908796B2 - Cu-Mg-P-based copper alloy plate excellent in mechanical formability and method for producing the same - Google Patents

Description

  The present invention relates to a Cu-Mg-P-based copper alloy sheet excellent in mechanical formability, and in particular, a Cu-Mg-P-based copper alloy sheet excellent in Erichsen value and excellent in stretch formability and its production. Regarding the method.

  As materials for terminals and connectors of electrical and electronic equipment, brass and phosphor bronze were generally used. Recently, electronic equipment such as mobile phones and notebook PCs are becoming smaller, thinner and lighter. Accordingly, the terminals and connector parts are also made smaller and have a narrow pitch between the electrodes. In addition, reliability around severe conditions at high temperatures is also required for use around automobile engines. Along with this, due to the necessity of maintaining the reliability of the electrical connection, further improvements in strength, conductivity, spring limit value, stress relaxation characteristics, machinability, fatigue resistance, etc. are required. Brass and phosphor bronze However, as an alternative, the applicant pays attention to Cu-Mg-P-based copper alloys as disclosed in Patent Documents 1 to 5, and has high quality and high reliability terminals and connectors having excellent characteristics. Copper alloy plate (trade name “MSP1”) for the market.

  In Patent Document 1, Mg: 0.3 to 2 wt%, P: 0.001 to 0.02 wt%, C: 0.0002 to 0.0013 wt%, oxygen: 0.0002 to 0.001 wt% %, The remainder consisting of Cu and inevitable impurities, and a copper alloy having a structure in which oxide particles containing fine Mg having a particle size of 3 μm or less are uniformly dispersed in the substrate A copper alloy sheet for manufacturing a connector is disclosed.

  Patent Document 2 contains, by weight, Mg: 0.1 to 1.0%, P: 0.001 to 0.02%, and the rest is a strip made of Cu and inevitable impurities, The crystal grains have an oval shape, the average minor axis of the elliptical crystal grains is 5 to 20 μm, and the average major axis / average minor axis value is 1.5 to 6.0. In order to form crystal grains, the average grain size is adjusted to be in the range of 5 to 20 μm in the final annealing immediately before the final cold rolling, and then the rolling rate is 30 to 85% in the final cold rolling step. A copper-stretched alloy strip that does not wear the mold within the range is disclosed.

Patent Document 3 discloses a copper alloy strip having a composition in which Mg is 0.3 to 2%, P is 0.001 to 0.1%, and the balance is Cu and inevitable impurities. The orientation of all pixels within the measurement area of the surface of the copper alloy strip is measured by an EBSD method using a scanning electron microscope with a scattered electron diffraction image system, and the orientation difference between adjacent pixels is 5 ° or more. When the boundary is regarded as the grain boundary, the area ratio of the crystal grains in which the average orientation difference between all the pixels in the crystal grains is less than 4 ° is 45 to 55% of the measurement area, and the tensile strength There was ^{641~708N / mm 2, Cu-Mg} -P -based copper alloy and a method of manufacturing the spring limit value is taken 472~503N / mm ² at a tensile strength and spring limit value of the balance at a high level disclosed Has been.

Patent Document 4 discloses a copper alloy strip having a composition of Mg: 0.3 to 2%, P: 0.001 to 0.1%, the balance being Cu and inevitable impurities. Measure the orientation of all the pixels within the measurement area of the surface of the copper alloy strip with a step size of 0.5 μm by the EBSD method using a scanning electron microscope with a scattered electron diffraction image system, and the orientation between adjacent pixels. When a boundary having a difference of 5 ° or more is regarded as a crystal grain boundary, the average value of the average orientation difference between all the pixels in the crystal grains in all the crystal grains is 3.8 to 4.2 °, and the tensile strength Copper alloy strip having a thickness of 641 to 708 N / mm ² , a spring limit value of 472 to 503 N / mm ² , and a stress relaxation rate of 12 to 19% after heat treatment at 200 ° C. for 1000 hours, and its production A method is disclosed.

Patent Document 5 describes a copper alloy strip having a composition in which Mg is 0.3 to 2%, P is 0.001 to 0.1%, and the balance is Cu and inevitable impurities. Measure the orientation of all the pixels within the measurement area of the surface of the copper alloy strip with a step size of 0.5 μm by the EBSD method using a scanning electron microscope with a scattered electron diffraction image system, and the orientation between adjacent pixels. When the boundary where the difference is 5 ° or more is regarded as a crystal grain boundary, the area ratio of crystal grains having an average orientation difference between all pixels in the crystal grains of less than 4 ° is 45 to 55% of the measurement area. The area average GAM of the crystal grains existing in the measurement area is 2.2 to 3.0 °, the tensile strength is 641 to 708 N / mm ² , and the spring limit value is 472 to 503 N / mm. ^2, both swing plane song in the number of repetitions of 1 × 106 times Fatigue limit copper alloy strip material and its manufacturing method are disclosed a 300~350N / mm ^2.

  Patent Document 6 describes an inexpensive copper alloy that is excellent in not only normal bending workability but also bending workability after notching while maintaining high conductivity and high strength, and excellent in stress relaxation resistance. A copper alloy plate material having a composition containing 0.2 to 1.2 mass% Mg and 0.001 to 0.2 mass% P, with the balance being Cu and inevitable impurities Assuming that the X-ray diffraction intensity of the {420} crystal plane on the plate surface is I {420} and the X-ray diffraction intensity of the {420} crystal plane of the pure copper standard powder is I0 {420}, I {420} / I0 { 420}> 1.0, the X-ray diffraction intensity of the {220} crystal plane on the plate surface of the copper alloy sheet is I {220}, and the X-ray diffraction intensity of the {220} crystal plane of the pure copper standard powder is I0 { 220}, 1.0 ≦ I {220} / I0 {2 0} copper alloy sheet having a crystal orientation is disclosed satisfying ≦ 3.5.

Japanese Patent Laid-Open No. 9-157774 Japanese Patent Laid-Open No. 6-340938 Japanese Patent No. 4516154 Japanese Patent No. 4563508 JP 2012-007231 A JP 2009-228013 A

Cu-Mg-P-based copper alloy sheets having excellent quality based on Patent Documents 1 to 5 are manufactured and sold under the trade name “MSP1” of the applicant, and are subjected to surface treatment and machining (mainly press working). After being applied, etc., it is widely used as a terminal and connector material.
Cu-Mg-P-based copper alloy plates are also capable of bending and press punching, as well as more formability for complex machining (to deal with recent complex and diverse terminal and connector shapes) Squeezing or stretch formability) is required. In particular, a high dimensional accuracy is often required for the stretch formability, and a Cu—Mg—P-based copper alloy sheet having a good Erichsen value indicating the formability is demanded along with cost reduction.
In the present invention, Cu-Mg-P having improved mechanical formability, particularly excellent Erichsen value and excellent stretch formability, while improving the applicant's trade name "MSP1" and maintaining its excellent properties. An object of the present invention is to provide a copper alloy sheet and a method for producing the same.

Conventionally, the present inventors have used the X-ray or SEM / EBSD method for each crystal orientation plane of the copper alloy structure surface of the applicant's trade name “MSP1”, particularly the {110} plane, {123} Various analyzes have been conducted focusing on the {111} plane, {100} plane, and as a result of intensive studies based on them, Mg: 0.2-1.2%, P: In a copper alloy plate having a composition of 0.001 to 0.2%, the balance being Cu and inevitable impurities, the surface parallel to the rolling surface is measured by an EBSD method using a scanning electron microscope with a backscattered electron diffraction image system. The diffraction intensity distribution (reverse pole figure) of the crystal plane is measured, the diffraction intensity of the {123} plane within the measurement area is I ₁ , the diffraction intensity of the {110} plane is I ₂ , and the diffraction intensity of the {100} plane is I _When I is ₃ , I ₁ / I ₃ is 15.0 to 20.0 and I ₂ / I ₃ is 15.0 to ₂ 0.0, the grain size of the crystal grains within the measurement area is 10 μm or less, and the area ratio of the crystal grains having a grain size of 5 μm or less is 75% or more while maintaining its excellent characteristics. The present inventors have found that the mechanical formability, particularly the Erichsen value, is good and has excellent stretch formability.
In other words, in order to improve the stretch formability, it is necessary to densify the surface structure of the Cu—Mg—P-based copper alloy under optimum conditions, increasing the formation of [{110} plane and {123} plane. Then, the formation of the {100} plane is reduced, and the diffraction intensity ratio of the {110} plane and the {123} plane and the {100} plane is within the optimum range, and the crystal grain size is 10 μm or less. It is achieved when the area ratio of crystal grains having a grain size of 5 μm or less is 75% or more.

In addition, the present inventors perform melting / casting, hot rolling, cold rolling, continuous annealing, finish cold rolling, and tension leveling in this order, under the following conditions (1) to (3): It has also been found that the Cu—Mg—P based copper alloy sheet of the present invention is optimally manufactured by carrying out hot rolling, cold rolling, continuous annealing, and tension leveling.
(1) A copper alloy ingot plate is prepared by melting and casting a predetermined component copper alloy, and hot rolling of the copper alloy ingot plate is performed at a rolling start temperature: 700 ° C. to 800 ° C., total hot rolling rate 80% or more, average rolling rate per pass; 15% to 30%, cold rolling, rolling rate; 50% or more, {123} plane and {110} plane And {100} plane diffraction intensity ratio and crystal grain size are made within the specified values (particularly, the formation of {110} is increased).
(2) By performing continuous annealing at a temperature of 300 ° C. to 550 ° C., time; 0.1 minutes to 10 minutes, recrystallization during annealing is suppressed as much as possible, and formation of {100} planes is suppressed. Within the specified value.
(3) the tension leveling, the line tension; 10N / mm ² ~140N / by performing in mm ^2, {110} by increasing the formation of surface housed within a prescribed value, the roller leveler surface roughness of the roll ( Ra): By carrying out at 0.01-0.10 micrometer, the friction of the roll of a roller leveler and a copper alloy plate is suppressed, and the compression strain of the side which is in contact with the roll of a roller leveler of a copper alloy plate is enlarged. By doing so, the structure of the copper alloy plate surface is densified, the formation of {123} planes is increased to fall within the specified value, and the crystal grain size also falls within the specified value.

That is, the Cu-Mg-P-based copper alloy plate of the present invention is, in mass%, Mg: 0.2-1.2%, P: 0.001-0.2%, the balance being Cu and inevitable impurities. This is a copper alloy plate having a certain composition, and the diffraction intensity distribution (reverse pole figure) of the crystal plane on the surface parallel to the rolling surface is measured by the EBSD method using a scanning electron microscope with a backscattered electron diffraction image system. When the diffraction intensity of the {123} plane within the area is I ₁ , the diffraction intensity of the [110} plane is I ₂ , and the diffraction intensity of the {100} plane is I ₃ , I ₁ / I ₃ is 15.0 to 20 0.0, I ₂ / I ₃ is 15.0 to 20.0, the grain size of the crystal grains within the measurement area is 10 μm or less, and the area ratio of crystal grains having a grain size of 5 μm or less is 75 % Or more.
Mg improves the strength without being dissolved in the Cu substrate and impairing conductivity. Further, P has a deoxidizing action at the time of melt casting, and improves the strength in the state of coexisting with the Mg component. When these Mg and P are contained within the above ranges, their characteristics can be effectively exhibited.

Patent Document 6 discloses a copper alloy sheet containing 0.2 to 1.2% by mass of Mg and 0.001 to 0.2% by mass of P, with the balance being Cu and inevitable impurities. When the X-ray diffraction intensity of the {420} crystal plane on the plate surface of the plate is I {420} and the X-ray diffraction intensity of the {420} crystal plane of the pure copper standard powder is I ₀ {420}, I {420} / I ₀ {420}> 1.0, the X-ray diffraction intensity of the {220} crystal plane on the plate surface of the copper alloy sheet is I {220}, and the X-ray diffraction intensity of the {220} crystal plane of the pure copper standard powder Is I ₀ {220}, when the crystal orientation satisfies 1.0 ≦ I {220} / I ₀ {220} ≦ 3.5, not only normal bending workability but also bending workability after notching And excellent stress relaxation resistance.
In this document, the X-ray diffraction pattern from the plate surface (rolled surface) of a Cu—Mg—P-based copper alloy generally has diffraction of four crystal planes {111}, {200}, {220}, and {311}. The Cu-Mg-P system is composed of peaks, and the X-ray diffraction intensity from other crystal planes is very small compared to the X-ray diffraction intensities from these crystal planes. In the copper alloy plate material, the X-ray diffraction intensity from the {420} plane is so weak as to be neglected, but according to the embodiment of the method for producing a copper alloy plate material according to this document, {420} is the main orientation. It is disclosed that a Cu—Mg—P-based copper alloy sheet having a texture as a component can be produced, and that the stronger the texture is developed, the more advantageous is the bending workability.

In the present invention, unlike the concept of this document, in the process of improving the mechanical formability of the applicant's trade name “MSP1”, Mg is 0.2 to 1.2 mass% and P is 0.2%. A copper alloy plate having a composition of 001 to 0.2% by mass, the balance being Cu and inevitable impurities, on the rolled surface by an EBSD method using a scanning electron microscope with a backscattered electron diffraction image system of the copper alloy plate The diffraction intensity distribution (inverse pole figure) of the crystal plane of the parallel surface is measured, the diffraction intensity of the {123} plane within the measurement area is I ₁ , the diffraction intensity of the {110} plane is I ₂ , and the {100} plane When the diffraction intensity is I ₃ , I ₁ / I ₃ is 15.0 to 20.0 and I ₂ / I ₃ is 15.0 to 20.0, that is, {123} plane and {110 } The formation of the surface is increased, the formation of the {100} surface is suppressed as much as possible, and the crystal grain size is 10 μm or less. Thus, by setting the area ratio of the crystal grains having a grain size of 5 μm or less to 75% or more, the copper alloy sheet has excellent mechanical formability, in particular, an Erichsen value, while maintaining the conventional characteristics. It has been found that it has stretch formability.
The effect cannot be obtained unless all of these three conditions (I ₁ / I ₃ , I ₂ / I ₃ , crystal grain size) are satisfied.
The conventional properties mean physical, mechanical, and various properties corresponding to 1 / 4H material, 1 / 2H material, H material, EH material, and SH material of the applicant's trade name “MSP1”.
Further, the {110} plane is an important factor involved in improving fatigue resistance at high temperatures, as disclosed in the applicant's PCT / JP2012 / 59257, as well as the stretch formability.
It is preferable that the values of I ₁ / I ₃ and I ₂ / I ₃ are large, but it is difficult to eliminate the formation of {100} planes to be suppressed because of problems in manufacturing technology, and I ₁ / I ₃ and I ₂ / I ₃ never exceeds 20.
By setting the area ratio of the crystal grains having a grain size of 10 μm or less and a grain size of 5 μm or less to 75% or more, the crystal grains have an optimum range and the surface is densified. If it is less than%, the surface is not sufficiently densified, and the expected effect cannot be obtained. In this case, the area ratio is a ratio of crystal grains having a grain size of 5 μm or less in all crystal grains within the measurement area.

In the present invention, the diffraction intensity distribution (reverse pole figure) of each crystal plane was measured by an EBSD method using a scanning electron microscope with a backscattered electron diffraction image system.
As a method for displaying the distribution of each crystal plane, there are a positive pole figure and an inverse pole figure, and the positive pole figure is a plane figure display in which the sample axis of the measurement sample is fixed, and the three-dimensional crystal plane is displayed. The status can be read. The inverted pole figure is a plane figure display in which the crystal axis of the measurement sample is fixed. In the present invention, this inverted pole figure is used to focus on the diffraction intensity of the {123} plane, the [110} plane, and the {100} plane. .
In addition, in the present invention, the evaluation of the stretch formability was performed using an Erichsen value (the depth at which the spherical protrusion penetrated until the center of the copper alloy thin film was pushed by the spherical protrusion and the copper alloy thin film was broken. (Numerical values expressed in units).

Further, the Cu—Mg—P-based copper alloy sheet having excellent fatigue resistance characteristics of the present invention further contains 0.0002 to 0.0013 mass% of C and 0.0002 to 0.001 mass% of oxygen. It is characterized by doing.
C is an element that is very difficult to enter into pure copper. However, when contained in a trace amount, C has an effect of suppressing the growth of oxide containing Mg. However, if the content is less than 0.0001% by mass, the effect is not sufficient. On the other hand, if the content exceeds 0.0013% by mass, it exceeds the solid solution limit and precipitates at the crystal grain boundary, causing intergranular cracking. It is not preferable because it causes embrittlement and cracking during bending. A more preferable range is 0.0003 to 0.0010 mass%.
Oxygen forms an oxide together with Mg, and if this oxide is fine and present in a very small amount, it is effective for reducing the wear of the punching die, but if its content is less than 0.0002% by mass, its effect is not sufficient, On the other hand, if the content exceeds 0.001% by mass, an oxide containing Mg grows greatly, which is not preferable. A more preferable range is 0.0003 to 0.008 mass%.
In addition, the Cu—Mg—P-based copper alloy sheet having excellent fatigue resistance characteristics of the present invention is further characterized by containing 0.001 to 0.03 mass% of Zr.
Zr contributes to the improvement of the tensile strength and the spring limit value by adding 0.001 to 0.03% by mass, and no effect can be expected outside the addition range.

The method for producing a Cu-Mg-P-based copper alloy sheet of the present invention is a method for producing the copper alloy sheet in a process of performing hot rolling, cold rolling, continuous annealing, finish cold rolling, and tension leveling in this order. The hot rolling is performed at a rolling start temperature: 700 ° C. to 800 ° C., a total hot rolling rate: 80% or more, an average rolling rate per pass: 15% to 30%, and the cold rolling is performed. The rolling annealing is performed at 50% or more, and the continuous annealing is performed at a temperature of 300 ° C. to 550 ° C., a time of 0.1 minutes to 10 minutes, and tension leveling is performed with a line tension of 10 N / mm ^2. ~ 140 N / mm < ² >, surface roughness (Ra) of roll of roller leveler; 0.01-0.10 [mu] m.

In the applicant's patent document 3, patent document 4, and patent document 5, as a manufacturing method of a Cu-Mg-P type copper alloy plate, hot rolling, solution treatment, finish cold rolling, and low temperature annealing are included in this order. When producing the copper alloy in the process, the hot rolling start temperature is 700 ° C. to 800 ° C., the total hot rolling rate is 90% or more, and the average rolling rate per pass is 10% to 35%. It is disclosed that the Vickers hardness of the copper alloy sheet after the solution treatment is adjusted to 80 to 100 Hv, and the low temperature annealing is performed at 250 to 450 ° C. for 30 seconds to 180 seconds. In Patent Document 4 of the applicant, it is further disclosed that the total rolling rate in finish cold rolling is 50 to 80%.
Moreover, in patent document 6, as a manufacturing method of a Cu-Mg-P type copper alloy plate, after performing the first rolling pass at 900 degreeC-600 degreeC as hot rolling in 900 degreeC-300 degreeC, it is less than 600 degreeC- Rolling at a rolling rate of 40% or more at 300 ° C, then cold rolling at a rolling rate of 85% or more, and then recrystallization annealing at 400 to 700 ° C and finish cold rolling at a rolling rate of 20 to 70% It is disclosed that a copper alloy sheet is produced by sequentially performing the above.

The manufacturing method of the Cu—Mg—P-based copper alloy sheet of the present invention is improved from the manufacturing method of the applicant's Patent Document 3, Patent Document 4, and Patent Document 5, and {110} plane, {123} by tension leveling The crystal grain size is adjusted by repetitively bending and applying tensile stress to the copper alloy plate by adjusting the crystal grain size by keeping the plane and crystal grain size within the specified range values, that is, with optimum tension leveling. } A major feature is to obtain a Cu-Mg-P-based copper alloy sheet having excellent stretch formability by increasing the surface formation and reducing the stress acting on individual grain boundaries by densifying the surface structure. It is.
Tension leveling corrects the flatness of the copper alloy plate by applying tension in the front-rear direction to the roller leveler (a device that repeatedly inserts a copper alloy plate into a roll following a zigzag and bends it in the opposite direction). The line tension is the tension applied to the copper alloy plate in the roller leveler by the inlet side and winding side tension load devices. Along with this line tension, the surface roughness (Ra) of each roll of the roller leveler also has a great influence on the densification of the surface structure of the copper alloy.

Specifically, the Cu—Mg—P-based copper alloy sheet of the present invention is optimally manufactured for the following manufacturing method and reason.
(1) A copper alloy ingot plate is prepared by melting and casting a predetermined component copper alloy, and hot rolling of the copper alloy ingot plate is performed at a rolling start temperature: 700 ° C. to 800 ° C., total hot rolling rate 80% or more, average rolling rate per pass; 15% to 30%, cold rolling, rolling rate; 50% or more, {123} plane and {110} plane And {100} plane diffraction intensity ratio and crystal grain size are made within the specified values (particularly, the formation of {110} is increased).
(2) By performing continuous annealing at a temperature of 300 ° C. to 550 ° C., time; 0.1 minutes to 10 minutes, recrystallization during annealing is suppressed as much as possible, and formation of {100} planes is suppressed. Within the specified value.
(3) the tension leveling, the line tension; 10N / mm ² ~140N / by performing in mm ^2, {110} by increasing the formation of surface housed within a prescribed value, the roller leveler surface roughness of the roll ( Ra); By carrying out at 0.01-0.10 micrometer, the friction with the roll of a roller leveler row and a copper alloy board is suppressed, and the compression strain of the side which is in contact with the roll of a roller leveler of a copper alloy board is carried out. By enlarging, the structure of the copper alloy plate surface is densified, the formation of {123} planes is increased to fall within the specified value, and the crystal grain size also falls within the specified value.
All three conditions (I ₁ / I ₃ , I ₂ / I ₃ , crystal grain size) are satisfied even if any one of these hot rolling, cold rolling, continuous annealing, and tension leveling manufacturing conditions is removed. In addition, it is not possible to obtain a Cu—Mg—P-based copper alloy plate excellent in mechanical formability.

The present invention provides a Cu-Mg-P-based copper alloy sheet having excellent mechanical formability, in particular, excellent Erichsen value and excellent stretch formability, and a method for producing the same.

It is the schematic for demonstrating the line tension and the roller leveler in the tension leveling in the manufacturing process of this invention.

Hereinafter, embodiments of the present invention will be described in detail.
[Component composition of copper alloy sheet]
The Cu—Mg—P-based copper alloy sheet of the present invention contains 0.2 to 1.2 mass% Mg and 0.001 to 0.2 mass% P, with the balance being Cu and inevitable impurities. Have
Mg improves the strength without being dissolved in the Cu substrate and impairing conductivity. Further, P has a deoxidizing action at the time of melt casting, and improves the strength in the state of coexisting with the Mg component. By containing these Mg and P in the above ranges, the characteristics can be effectively exhibited.
Further, the Cu—Mg—P-based copper alloy sheet of the present invention further contains 0.0002 to 0.0013 mass% C and 0.0002 to 0.001 mass% oxygen with respect to the above basic composition. It is preferable to do this.
C is an element that is very difficult to enter into pure copper. However, when contained in a trace amount, C has an effect of suppressing the growth of oxide containing Mg. However, if the content is less than 0.0001% by mass, the effect is not sufficient. On the other hand, if the content exceeds 0.0013% by mass, it exceeds the solid solution limit and precipitates at the crystal grain boundary, causing intergranular cracking. It is not preferable because it causes embrittlement and cracking during bending. A more preferable range is 0.0003 to 0.0010 mass%.
Oxygen forms an oxide together with Mg, and if this oxide is fine and present in a very small amount, it is effective for reducing the wear of the punching die, but if its content is less than 0.0002% by mass, its effect is not sufficient, On the other hand, if the content exceeds 0.001% by mass, an oxide containing Mg grows greatly, which is not preferable. A more preferable range is 0.0003 to 0.008 mass%.
Further, the Cu—Mg—P-based copper alloy plate of the present invention is further 0.001 to 0 with respect to the above basic composition or with respect to the above composition containing C and oxygen. It is preferable to contain 0.03% by mass of Zr.
Zr contributes to the improvement of the tensile strength and the spring limit value by adding 0.001 to 0.03% by mass, and no effect can be expected outside the addition range.

[A texture of copper alloy sheet]
The Cu-Mg-P-based copper alloy sheet of the present invention is a composition in which Mg is 0.2 to 1.2%, P is 0.001 to 0.2%, and the balance is Cu and inevitable impurities. This is a copper alloy plate with a backscattered electron diffraction image system, and the diffraction intensity distribution (reverse pole figure) of the crystal plane on the surface parallel to the rolling surface is measured by the EBSD method using a scanning electron microscope. When the diffraction intensity of the {123} plane is I ₁ , the diffraction intensity of the [110} plane is I ₂ , and the diffraction intensity of the {100} plane is I ₃ , I ₁ / I ₃ is 15.0 to 20.0. I ₂ / I ₃ is 15.0 to 20.0, the grain size of the crystal grains in the measurement area is 10 μm or less, and the area ratio of the crystal grains whose grain size is 5 μm or less is 75% or more It is.

Patent Document 6 discloses a copper alloy sheet containing 0.2 to 1.2% by mass of Mg and 0.001 to 0.2% by mass of P, with the balance being Cu and inevitable impurities. When the X-ray diffraction intensity of the {420} crystal plane on the plate surface of the plate is I {420} and the X-ray diffraction intensity of the {420} crystal plane of the pure copper standard powder is I ₀ {420}, I {420} / I ₀ {420}> 1.0, the X-ray diffraction intensity of the {220} crystal plane on the plate surface of the copper alloy sheet is I {220}, and the X-ray diffraction intensity of the {220} crystal plane of the pure copper standard powder Is I ₀ {220}, when the crystal orientation satisfies 1.0 ≦ I {220} / I ₀ {220} ≦ 3.5, not only normal bending workability but also bending workability after notching And excellent stress relaxation resistance.
In this document, the X-ray diffraction pattern from the plate surface (rolled surface) of a Cu—Mg—P-based copper alloy generally has diffraction of four crystal planes {111}, {200}, {220}, and {311}. The Cu-Mg-P system is composed of peaks, and the X-ray diffraction intensity from other crystal planes is very small compared to the X-ray diffraction intensities from these crystal planes. In the copper alloy plate material, the X-ray diffraction intensity from the {420} plane is so weak as to be neglected, but according to the embodiment of the method for producing a copper alloy plate material according to this document, {420} is the main orientation. It is disclosed that a Cu—Mg—P-based copper alloy sheet having a texture as a component can be produced, and that the stronger the texture is developed, the more advantageous is the bending workability.

In the present invention, unlike the concept of this document, in the process of improving the mechanical formability of the applicant's trade name “MSP1”, a scanning electron microscope with a backscattered electron diffraction image system of a copper alloy plate is used. The diffraction intensity distribution (reverse pole figure) of the crystal plane parallel to the rolling surface is measured by the EBSD method according to, and the diffraction intensity of the {123} plane within the measurement area is I ₁ and the diffraction intensity of the {110} plane is When the diffraction intensity of the I ₂ and {100} planes is I ₃ , I ₁ / I ₃ is 15.0 to 20.0, and I ₂ / I ₃ is 15.0 to 20.0. , The formation of {123} plane and {110} plane is increased, the formation of {100} plane is suppressed as much as possible, and the crystal grain size is 10 μm or less and the grain size is 5 μm or less. By setting the area ratio to 75% or more, the copper alloy sheet can be mechanically grown while maintaining the conventional characteristics. It has been found that the formability, particularly the Erichsen value, is good and has excellent stretch formability.
The effect cannot be expected unless all of these three conditions (I ₁ / I ₃ , I ₂ / I ₃ , crystal grain size) are satisfied.
The conventional properties mean physical, mechanical, and various properties corresponding to 1 / 4H material, 1 / 2H material, H material, EH material, and SH material of the applicant's trade name “MSP1”.
Further, the [110} plane is an important factor involved not only in the stretch formability but also in improving the fatigue resistance at high temperatures as disclosed in the applicant's PCT / JP2012 / 59257.
It is preferable that the values of I ₁ / I ₃ and I ₂ / I ₃ are large, but it is difficult to eliminate the formation of {100} planes to be suppressed because of problems in manufacturing technology, and I ₁ / I ₃ and I ₂ / I ₃ never exceeds 20.
By setting the area ratio of the crystal grains having a grain size of 10 μm or less and a grain size of 5 μm or less to 75% or more, the crystal grains have an optimum range and the surface is densified. If it is less than%, the surface is not sufficiently densified, and the expected effect cannot be obtained. In this case, the area ratio is a ratio of crystal grains having a grain size of 5 μm or less in all crystal grains within the measurement area.

[Measurement of diffraction intensity distribution (reverse pole figure) of each crystal plane of copper alloy sheet, Erichsen value]
In the present invention, the diffraction intensity distribution (reverse pole figure) of each crystal plane was measured by an EBSD method using a scanning electron microscope with a backscattered electron diffraction image system.
As a method for displaying the distribution of each crystal plane, there are a positive pole figure and an inverse pole figure, and the positive pole figure is a plane figure display in which the sample axis of the measurement sample is fixed, and the three-dimensional crystal plane is displayed. The status can be read. The inverse pole figure is a plane figure display in which the crystal axis of the measurement sample is fixed. In the present invention, the inverse pole figure is used and attention is paid to the diffraction intensity of the {123} plane, the {110} plane, and the {100} plane. .
In addition, in the present invention, the evaluation of the stretch formability is performed using an Erichsen value (the depth at which the spherical protrusion penetrates until the copper alloy sheet is broken by pressing the center with a spherical protrusion on the annular base of the copper alloy sheet) (Numerical values expressed in units).

[Method for producing copper alloy sheet]
The method for producing a Cu-Mg-P-based copper alloy sheet of the present invention is a method for producing the copper alloy sheet in a process of performing hot rolling, cold rolling, continuous annealing, finish cold rolling, and tension leveling in this order. The hot rolling is performed at a rolling start temperature: 700 ° C. to 800 ° C., a total hot rolling rate: 80% or more, an average rolling rate per pass: 15% to 30%, and the cold rolling is performed. The rolling annealing is performed at 50% or more, and the continuous annealing is performed at a temperature of 300 ° C. to 550 ° C., a time of 0.1 minutes to 10 minutes, and tension leveling is performed with a line tension of 10 N / mm ^2. ~ 140 N / mm < ² >, surface roughness (Ra) of roll of roller leveler; 0.01-0.10 [mu] m.

In the applicant's patent document 3, patent document 4, and patent document 5, as a manufacturing method of a Cu-Mg-P type copper alloy plate, hot rolling, solution treatment, finish cold rolling, and low temperature annealing are included in this order. When producing the copper alloy in the process, the hot rolling start temperature is 700 ° C. to 800 ° C., the total hot rolling rate is 90% or more, and the average rolling rate per pass is 10% to 35%. It is disclosed that the Vickers hardness of the copper alloy sheet after the solution treatment is adjusted to 80 to 100 Hv, and the low temperature annealing is performed at 250 to 450 ° C. for 30 seconds to 180 seconds. In the patent document 4 of the applicant, it is further disclosed that the total rolling rate in the finish cold rolling is performed at 50 to 80%.
Moreover, in patent document 6, as a manufacturing method of a Cu-Mg-P type copper alloy plate, after performing the first rolling pass at 900 degreeC-600 degreeC as hot rolling in 900 degreeC-300 degreeC, it is less than 600 degreeC- Rolling at a rolling rate of 40% or more at 300 ° C, then cold rolling at a rolling rate of 85% or more, and then recrystallization annealing at 400 to 700 ° C and finish cold rolling at a rolling rate of 20 to 70% It is disclosed that a copper alloy sheet is produced by sequentially performing the above.

The manufacturing method of the Cu—Mg—P-based copper alloy sheet of the present invention is improved from the manufacturing method of the applicant's Patent Document 3, Patent Document 4, and Patent Document 5, and {110} plane, {123} by tension leveling The crystal grain size is adjusted by repetitively bending and applying tensile stress to the copper alloy plate by adjusting the crystal grain size by keeping the plane and crystal grain size within the specified range values, that is, with optimum tension leveling. } A major feature is to obtain a Cu-Mg-P-based copper alloy sheet having excellent stretch formability by increasing the surface formation and reducing the stress acting on individual grain boundaries by densifying the surface structure. It is.
Tension leveling is a process of correcting the flatness of a material by applying tension in the front-rear direction to a roller leveler that repeatedly bends the material in rolls arranged in a staggered manner in the reverse direction. In this tension leveling, a back tension, a line tension, and a front tension are applied to the material. The back tension is the tension applied to the material between the uncoiler and the input side tension load device, and the line tension is the tension applied to the material in the roller leveler by the input side and winding side tension load devices. The front tension is the tension applied to the material between the recoiler and the winding side tension load device.
As shown in FIG. 1, the copper alloy plate 6 wound around the uncoiler 9 passes through the entrance side tension load device 11 of the tension leveler 10 and is repeatedly bent by the roller leveler 13 to become the copper alloy plate 7. After passing through the side tension load device 12, it becomes a copper alloy plate 8 and is wound around the recoiler 14. At this time, the back tension B <b> 1 is loaded on the copper alloy plate 6 between the uncoiler 9 and the entry side tension load device 11. The line tension L is applied to the copper alloy plate 7 between the inlet side tension load device 11 and the winding side tension load device 12 (the tension is uniform in the roller leveler 13). The front tension F <b> 1 is a tension applied to the copper alloy plate 8 between the recoiler 14 and the winding side tension load device 12.
Along with the line tension L, the surface roughness (Ra) of each roll of the roller leveler 13 greatly affects the densification of the surface structure of the copper alloy.

Specifically, the Cu—Mg—P-based copper alloy sheet of the present invention is optimally manufactured for the following manufacturing method and reason.
(1) A copper alloy ingot plate is prepared by melting and casting a predetermined component copper alloy, and hot rolling of the copper alloy ingot plate is performed at a rolling start temperature: 700 ° C. to 800 ° C., total hot rolling rate 80% or more, average rolling rate per pass; 15% to 30%, cold rolling, rolling rate; 50% or more, {123} plane and {110} plane And {100} plane diffraction intensity ratio and crystal grain size are made within the specified values (particularly, the formation of {110} is increased).
(2) By performing continuous annealing at a temperature of 300 ° C. to 550 ° C., time; 0.1 minutes to 10 minutes, recrystallization during annealing is suppressed as much as possible, and formation of {100} planes is suppressed. Within the specified value.
(3) the tension leveling, the line tension; 10N / mm ² ~140N / by performing in mm ^2, {110} by increasing the formation of surface housed within a prescribed value, the roller leveler surface roughness of the roll ( Ra); By carrying out at 0.01-0.10 micrometer, the friction with the roll of a roller leveler row and a copper alloy board is suppressed, and the compression strain of the side which is in contact with the roll of a roller leveler of a copper alloy board is carried out. By enlarging, the structure of the copper alloy plate surface is densified, the formation of {123} planes is increased to fall within the specified value, and the crystal grain size also falls within the specified value.
All three conditions (I ₁ / I ₃ , I ₂ / I ₃ , crystal grain size) are satisfied even if any one of these hot rolling, cold rolling, continuous annealing, and tension leveling manufacturing conditions is removed. In addition, it is not possible to obtain a Cu—Mg—P-based copper alloy plate excellent in mechanical formability.

The copper alloy having the composition shown in Table 1 was melted in a reducing atmosphere with an electric furnace to produce an ingot having a thickness of 150 mm, a width of 500 mm, and a length of 3000 mm. The melted ingot was hot rolled at a rolling start temperature, a total hot rolling rate, and an average rolling rate per pass shown in Table 1 to obtain a copper alloy sheet. After removing 0.5 mm of oxide scale on both surfaces of this copper alloy sheet with a mill, cold rolling was performed at the rolling rate shown in Table 1, and continuous annealing shown in Table 1 was performed, and the rolling rate was 70% to 85%. The finish cold rolling was performed, tension leveling shown in Table 1 was performed, and Cu—Mg—P-based copper alloy thin plates shown in Examples 1 to 10 and Comparative Examples 1 to 7 having a thickness of about 0.2 mm were manufactured. . Examples 1 to 10 are the "H material" equivalent products according to the product name "MSP1" of the applicant.

Samples were cut from these copper alloy thin plates, and the diffraction intensity distribution (reverse pole figure) of each crystal plane parallel to the rolling surface was measured with a scanning electron microscope with a backscattered electron diffraction image system (Hitachi model: SU-70). ) By EBSD (manufactured by TSL Solutions Co., Ltd.), and I ₁ / I ₃ and I ₂ / I ₃ are calculated from the diffraction intensities of the {123}, [110}, and {100} planes. did. As the measurement control software, OIM Data Collection Ver.5 (manufactured by TSL Solutions Inc.) was used.
Further, the crystal grain size of each sample was measured by the cutting method of JISH0501 after etching the plate surface (rolled surface) of the copper alloy plate, etching the surface, and observing the surface with an optical microscope.
The results are shown in Table 2.

Next, the electrical conductivity, tensile strength, stress relaxation rate, and spring limit value of each sample were measured.
The electrical conductivity was measured according to the electrical conductivity measurement method of JISH0505.
Tensile strength was obtained by collecting five test pieces (JISZ2201 No. 5 test piece) for LD (rolling direction) and TD (direction perpendicular to the rolling direction and the plate thickness direction), respectively. A tensile test based on JISZ2241 was performed on the test piece, and the tensile strengths of LD and TD were determined by average values.
For the stress relaxation rate, a test piece having a width of 12.7 mm and a length of 120 mm (hereinafter, this length is defined as L0) is used. The test piece has a length of 110 mm and a depth of 3 mm. The test piece is curvedly set in a jig having a horizontal longitudinal groove so that the center portion of the test piece bulges upward (distance between both end portions of the test piece at this time: 110 mm is L1). Hold at 1000C for 1000 hours, measure the distance (hereinafter referred to as L2) between both ends of the test piece that can be placed in a state removed from the jig after heating, and calculate: (L0-L2) / It calculated | required by calculating by (L0-L1) * 100%.
The spring limit value is determined based on JIS-H3130 by measuring the amount of permanent deflection by a moment type test. T. T. et al. Kb0.1 (maximum surface stress value at the fixed end corresponding to a permanent deflection of 0.1 mm) was calculated.
Next, the overhang processability of each sample was evaluated by the Erichsen value by the JISZ2247A method.
These results are shown in Table 3.

As shown in Table 2 and Table 3, in Examples 1 to 10, the diffraction intensities of I ₁ / I ₃ and I ₂ / I ₃ are both 15.0 to 20.0, and the maximum crystal grain size is 10 μm. Hereinafter, the area ratio of crystal grains having a grain size of 5 μm or less is 75% or more.
As a result, the tensile strength is as high as 510 to 575 N / mm ² , the spring limit value is as high as 385 to 389 Kb0.1, while the stress relaxation rate is as low as 12 to 18 and the Erichsen value is as high as 8.8 or more. doing.
On the other hand, in Comparative Examples 1 to 7, the diffraction intensities of I ₁ / I ₃ and I ₂ / I ₃ are both less than 15.0, the maximum crystal grain size is larger than 10 μm, and the grain size is 5 μm or less. The area ratio is less than 75%. For this reason, the tensile strength is 515 N / mm ² or less, the spring limit value is 386 Kb 0.1 or less, and the stress relaxation rate is 20 or more except for Comparative Example 1, and the Erichsen value is 8.6 or less. Stay.

  From these results, it can be seen that the Cu—Mg—P-based copper alloy plate produced by the production method of the present invention has a good Erichsen value and excellent stretch formability as compared with the comparative example.

  Although the embodiment of the present invention has been described above, the present invention is not limited to this description, and various modifications can be made without departing from the spirit of the present invention. For example, cold rolling and continuous annealing are repeatedly performed in the manufacturing method, and strain relief annealing is performed after tension leveling.

6 Copper alloy plate 7 Copper alloy plate 8 Copper alloy plate 9 Uncoiler 10 Tension leveler 11 Input side tension load device 12 Winding side tension load device 13 Roller leveler 14 Recoiler B1 Back tension F1 Front tension L Line tension

Claims (4)

Backscattered electron diffraction image system comprising, by mass%, a copper alloy plate having a composition of Mg: 0.2-1.2%, P: 0.001-0.2%, the balance being Cu and inevitable impurities The diffraction intensity distribution (reverse pole figure) of the crystal plane parallel to the rolling surface is measured by the EBSD method using the attached scanning electron microscope, and the diffraction intensity of the {123} plane within the measurement area is represented by I ₁ , {110 } When the diffraction intensity of the plane is I ₂ and the diffraction intensity of the {100} plane is I ₃ , I ₁ / I ₃ is 15.0 to 20.0, and I ₂ / I ₃ is 15.0 to 20 Cu—Mg—P-based copper having a crystal grain size within a measurement area of 10 μm or less and an area ratio of crystal grains having a grain size of 5 μm or less of 75% or more. Alloy plate.
The Cu-Mg-P-based copper alloy plate according to claim 1, further comprising 0.0002 to 0.0013 mass% C and 0.0002 to 0.001 mass% oxygen. .
Furthermore, 0.001-0.03 mass% Zr is contained, The Cu-Mg-P type copper alloy plate of Claim 1 or Claim 2 characterized by the above-mentioned.
It is a manufacturing method of the Cu-Mg-P type copper alloy plate of any one of Claims 1-3, Comprising: Hot rolling, cold rolling, continuous annealing, finish cold rolling, tension leveling is carried out. In producing the copper alloy sheet in the steps performed in this order, the hot rolling is performed at a rolling start temperature: 700 ° C. to 800 ° C., a total hot rolling rate: 80% or more, an average rolling rate per pass: 15 The cold rolling is performed at a rolling rate of 50% or more, and the continuous annealing is performed at a temperature of 300 ° C. to 550 ° C., a time of 0.1 minutes to 10 minutes. carried by, the tension leveling, the line ^{tension; 10N / mm 2 ~140N / mm} 2, the surface roughness of the roller leveler roll (Ra); which comprises carrying out at 0.01～0.10Myuemu Cu- The manufacturing method of a Mg-P type copper alloy plate.

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