JP5833892B2 - Modified cross-section copper alloy sheet with low bending anisotropy and excellent stress relaxation resistance, and method for producing the same - Google Patents

Description

  In the present invention, Zr in mass%: 0.05 to 0.2%, Cr: 0.2 to 0.4%, the balance is composed of Cu and inevitable impurities, and has low bending anisotropy. The present invention relates to a modified cross-section copper alloy sheet having excellent stress relaxation characteristics and a method for producing the same.

The deformed cross-section copper alloy plate with thick and thin parts aligned in the width direction is stamped or bent with a press and then plated as necessary to produce connectors, lead frames, etc. It is used as a material for electrical and electronic parts, and is required to have heat resistance, electrical conductivity, heat dissipation and the like.
Generally, this modified cross-section copper alloy plate is produced by a flat plate processing step for producing a flat plate having a certain thickness in the plate width direction from a copper alloy ingot, and a variant having a different thickness in the plate width direction using the flat plate. It is manufactured by a profile processing step for manufacturing a cross-sectional plate. The flat plate processing step includes soaking of the copper alloy ingot, hot rolling, cold rolling, annealing, and then cold rolling performed as necessary. In the special shape processing process, after processing the flat plate produced by the flat plate processing step into the final product shape, it is cut to the required width, followed by rough cold working, annealing, finish cold working, slitter processing, as required It consists of each process of correction performed. In this case, annealing may not be performed in the middle of cold working, but may be performed after finishing cold working. Further, the cold working in the deforming process is performed by cold rolling using a deformed roll, or cold rolling or forging using a deformed die, and different processing methods may be combined.
Cu-Fe-P-based copper alloy, Cu-Ni-Si-based copper alloy, etc. are frequently used as the material for the irregular cross-section copper alloy plate, but with the recent further miniaturization of electrical and electronic parts, The current density flowing through the contact members and frictional members incorporated in the inside is increasing, and Cu-Zr-Cr copper alloys having excellent conductivity and strength are also being used as materials. .

  In Patent Document 1, a flat plate having a certain thickness in the plate thickness direction is manufactured from the ingot, and the flat plate is cold-rolled by a deformed roll to obtain a modified cross-section copper alloy plate having a different thickness in the plate width direction. In manufacturing, a deformed cross-section copper alloy sheet having high heat resistance, high conductivity, and excellent bending workability is disclosed without being annealed once in the middle or at the end of cold rolling with a deformed roll. ing. Ni: 0.03-0.5 mass%, P: 0.01-0.2 mass% is contained, Ni / P which is a mass ratio of Ni and P is 2-10, the remainder copper and unavoidable A copper alloy made of impurities is used. Desirably, it contains Sn: 0.005 to 0.5% or / and Fe: 0.005 to 0.20%. If necessary, it contains Zn: 0.005 to 0.5%. In the cold rolling with a deformed roll, the cold working rate of the thin portion is set to 30 to 90%.

  Patent Document 2 discloses a copper alloy strip for terminals and a method for manufacturing the same, which have good bending workability and can easily form a core crimping portion and a fitting convex portion with high strength. ing. A copper alloy strip for a terminal for manufacturing a terminal, which is composed of an aging precipitation type copper alloy, and a thick plate portion having a thick plate thickness in a cross section perpendicular to the longitudinal direction of the strip, and the thick plate And the ratio TS1 / TS2 between the tensile strength TS1 of the thick plate portion and the tensile strength TS2 of the thin plate portion is in the range of 1 <TS1 / TS2 ≦ 1.4. Is set to

JP 2007-39735 A JP 2009-9887 A

  Due to its material properties, the Cu-Cr-Zr-based deformed cross-section copper alloy sheet manufactured by the conventional manufacturing method is easily formed into a fiber shape in the rolling direction by deformed rolling, and the bending process is different. In particular, the difference between the bending workability in the BadWay direction and the bending workability in the GoodWay direction is large, the stress relaxation resistance is not sufficient, and the tolerance of the dimensional accuracy of the formed deformed portion ( (Dispersion) was large.

  In the present invention, the above-described drawbacks are improved, a Cu-Cr-Zr-based deformed cross-section copper alloy sheet having less bending anisotropy, sufficient stress relaxation resistance and excellent dimensional accuracy, and production thereof It aims to provide a method.

As a result of intensive studies, the present inventors have conducted bending workability in the BadWay direction of a Cu-Cr-Zr-based deformed cross-section copper alloy sheet (the minimum bending radius R at which no crack is generated in a 90 ° W bending test in accordance with JIS H3110) And the thickness t (hereinafter referred to as R / t) and the difference in bending workability (R / t) in the GoodWay direction, the profile rolling process is performed between the reciprocating rolling roll and the die forming surface. When a flat copper alloy material is sandwiched and rolled continuously, the elongation of the copper alloy material in the width direction is W ₁ , and the elongation of the copper alloy material in the rolling direction is W ₂ , W ₁ / W ₂ It was found that by carrying out at 1.4 to 2.3, the anisotropy was reduced within a predetermined range.
In addition, the azimuth difference between adjacent pixels is measured by measuring the azimuth of all the pixels within the measurement area of the surface of the thin-walled copper alloy plate by the EBSD method using a scanning electron microscope with a backscattered electron diffraction image system. GOS1, the average value of the average orientation difference between all the pixels in the crystal grains in all the crystal grains when the boundary having an angle of 5 ° or more is regarded as the crystal grain boundary, When measuring the orientation of all pixels within the measurement area and considering the boundary where the orientation difference between adjacent pixels is 5 ° or more as the grain boundary, the average orientation between all pixels in the crystal grains in all the crystal grains It has also been found that when the average value of the differences is GOS2, excellent stress relaxation resistance is exhibited when GOS1 / GOS2 is in the range of 0.9 to 1.4.
_Further, the W 1 / _{W 2} and 1.4 to 2.3, an average feed rate of the modified cross-section copper alloy plate after profiled rolling A (mm / min), the thickness of the thin portion of the modified cross-section copper alloy sheet Is T (mm), and the number of reciprocations of the rolling roll is B (times / min), and (A / B) / T is carried out at 1.5 to 70. We have also found that the tolerance of accuracy can be reduced.

That is, the odd-shaped cross-section copper alloy sheet having low bending anisotropy and excellent stress relaxation characteristics of the present invention is
It is a modified cross-section copper alloy plate in which a thick part and a thin part are arranged in the width direction, and is Zr in mass%: 0.05 to 0.2%, Cr: 0.2 to 0.4%, and the balance is Cu With regard to bending workability, which is a ratio (R / t) between a minimum bending radius R and a sheet thickness t, which has a composition consisting of inevitable impurities and does not generate cracks in a 90 ° W bending test according to JIS H3110 R ₂ / R ₁ is 0.8 to 1.7 when the bending workability (R / t) in the direction is R ₂ and the bending workability (R / t) in the GoodWay direction is R ₁ , Measure the azimuth of all pixels within the measurement area of the surface of the thin part by EBSD method using a scanning electron microscope with a scattered electron diffraction image system, and determine the boundary where the azimuth difference between adjacent pixels is 5 ° or more. All grains within all grains when considered as grain boundaries. The average value of the average orientation difference between cells is GOS1, the orientation of all pixels within the measurement area of the surface of the thick part is measured, and the boundary where the orientation difference between adjacent pixels is 5 ° or more is defined as a grain boundary. GOS1 / GOS2 is 0.9 to 1.4, where GOS2 is the average value of the average orientation difference between all pixels in the crystal grains in all crystal grains.

Cr is an alloy element that precipitates in the copper matrix and improves strength by subjecting the copper alloy to solution treatment and then aging treatment. If the Cr content is less than 0.2% by mass, the effect of precipitation is insufficient, and if it exceeds 0.4% by mass, the effect of improving the strength cannot be obtained.
Zr is an alloy element that precipitates in the copper matrix phase by aging treatment after solution treatment of the copper alloy, thereby improving strength and heat resistance. The content of Zr affects the amount and size of the formed precipitated particles and changes the balance between conductivity and strength, but by containing 0.05 to 0.2% by mass, Both conductivity and strength can be balanced in a high dimension. If the content of Zr is less than 0.05% by mass, the effect due to the precipitation action is insufficient, and the stress relaxation resistance also decreases, and if it exceeds 0.2% by mass, the shape of the Cu—Zr precipitate tends to be coarse. Further, the effect of improving the strength cannot be obtained, which causes a decrease in bending workability.
When R ₂ / R _1, which is the ratio of the bending workability R _{2 in} the BadWay direction and the bending workability R _{1 in the} GoodWay direction, is less than 0.8 or exceeds 1.7, the anisotropy of the bending workability In particular, it often causes troubles in stamping and bending with a press.
When GOS1 / GOS2 is less than 0.9 or exceeds 1.4, the stress relaxation resistance is deteriorated.

The deformed cross-section copper alloy sheet having low bending anisotropy and excellent stress relaxation characteristics of the present invention is further characterized by containing Si: 0.005 to 0.03% by mass%.
When Si is added together with Zr, the overall strength is further improved. If the Si content is less than 0.005% by mass, the effect is not sufficient, and if it exceeds 0.03% by mass, the conductivity is lowered and the bending workability is adversely affected.

The method for producing a deformed cross-section copper alloy sheet with low bending anisotropy and excellent stress relaxation characteristics according to the present invention is applied to a flat copper alloy material after cold rolling, deformed rolling, finish rolling, and straightening. When producing the deformed cross-section copper alloy sheet in a process including aging treatment in this order, the deformed rolling process is performed by sandwiching the flat copper alloy material between the reciprocating rolling roll and the die forming surface. In this case, continuous rolling is performed, and W ₁ / W ₂ is carried out at 1.4 to 2.3 when the elongation in the width direction is W ₁ (%) and the elongation in the rolling direction is W ₂ (%). Then, the straightening process is performed such that the plastic strain of the deformed cross-section copper alloy sheet is 0.05% to 1.0%.

Zr in mass%: 0.05 to 0.2%, Cr: 0.2 to 0.4%, the balance is a flat copper alloy material having a composition consisting of Cu and inevitable impurities, profile rolling, finish rolling A deformed cross-section copper alloy plate is manufactured by performing a process including processing, straightening, and aging treatment in this order.
In the profile rolling process, the flat copper alloy material is sandwiched between the reciprocating rolling roll and the forming surface of the die and continuously rolled, and the elongation in the width direction of the rolled copper alloy material is W ₁ . in the case where the growth was _{W 2,} to implement the _W 1 / W ₂ at 1.4 to 2.3.
When W ₁ / W ₂ is less than 1.4, R ₂ / R ₁ exceeds 1.7 and the tolerance (variation) in dimensional accuracy tends to deteriorate, and when W ₁ / W ₂ exceeds 2.3, The rolled structure is easily formed in a fiber shape in the rolling direction, and R ₂ / R ₁ is less than 0.8, and the anisotropy of bending workability is increased.
The finish rolling process is a rolling process that does not affect the anisotropy of the bending workability, and there is no distribution in the surface hardness, and an irregular cross-section alloy plate having uniform physical properties in the thick and thin portions is obtained. Therefore, it is preferable to carry out by cold rolling using a rolling roll comprising a step roll and a flat roll.
The straightening process is a process that mainly corrects the bending of the deformed cross-section copper alloy plate. The uncoiler that feeds out the coil of the deformed cross-section copper alloy plate at a constant speed, and applies a predetermined tension to the fed out deformed cross-section copper alloy plate. By using a stretch mechanism to make the desired deformed cross-section copper alloy plate with a target, a device having a recoiler that winds the deformed cross-section copper alloy plate that passed through the stretch mechanism at a constant speed, the plastic strain of the deformed cross-section copper alloy plate in the stretch mechanism Is carried out so as to be 0.05% to 1.0%.
In the stretch mechanism, one end of the deformed cross-section copper alloy plate is basically fixed, and the other end is moved to apply a predetermined tension (tensile amount). At this time, the tension (tensile amount) and strain (%) The relationship is expressed by: strain = (tensile amount / interval of chuck before tension) = elastic strain + plastic strain, and the plastic strain can be obtained by strain-elastic strain.
If the plastic strain is less than 0.05%, GOS1 / GOS2 exceeds 1.4, and if the plastic strain exceeds 1.0%, GOS1 / GOS2 is less than 0.9. This reduces the stress relaxation resistance.
The aging treatment is not at the stage of producing the flat copper alloy material, but can be carried out after the deforming process step to adjust the precipitation state of the precipitated particles in the thick part and the thin part, respectively. In addition, it is possible to adjust the properties such as the tensile strength and conductivity of the thin-walled portion within a predetermined range, and in order to enhance this effect, it is preferable to carry out after finishing rolling.

The method for producing a deformed cross-section copper alloy sheet with less anisotropy of bending work and excellent stress relaxation characteristics according to the present invention further includes an average feed of the deformed cross-section copper alloy sheet after the deformed rolling process in the deformed rolling process. When the speed is A (mm / min), the thickness of the thin-walled copper alloy sheet is T (mm), and the reciprocating rotation speed of the rolling roll is B (times / min), (A / B) / T is carried out at 1.5 to 70.
When (A / B) / T is less than 1.5 or exceeds 70, the tolerance (variation) in the dimensional accuracy of the thick-walled portion and thin-walled portion of the deformed cross-section copper alloy plate to be formed increases.

  According to the present invention, Zr in mass%: 0.05 to 0.2%, Cr: 0.2 to 0.4%, and the balance is composed of Cu and inevitable impurities, and has low bending anisotropy and resistance. A deformed cross-section copper alloy sheet having excellent stress relaxation characteristics and a method for producing the same are provided.

About one Embodiment of the manufacturing method of the irregular cross-section copper alloy board of this invention, a flat copper alloy raw material, a rough irregular cross-section copper alloy board, a finishing irregular cross-section copper alloy board, and the irregular cross-section copper alloy board after correction are shown in order of a manufacturing process. It is a perspective view. It is a front view which shows the die | dye and rolling roll which are used by the profile rolling process in one Embodiment. It is a top view which shows the molding surface of the die | dye of FIG. It is a perspective view which shows the step roll and flat roll used by finish rolling. It is a schematic block diagram of the correction apparatus used by the correction process in one Embodiment of this invention.

Hereinafter, the manufacturing method of the irregular cross-section strips according to the present invention has a composition composed of Zr in mass%: 0.05 to 0.2%, Cr: 0.2 to 0.4%, the balance being Cu and inevitable impurities. An embodiment applied to the production of a deformed cross section made of a copper alloy will be described.
A modified cross-section copper alloy plate 1 of the present invention is a modified cross-section copper alloy plate (see FIG. 1) in which a thick portion 2 and a thin portion 3 are arranged in the width direction. The thin portion 3 is disposed, and the inclined portion 4 having a predetermined rising inclination angle β is formed between the thick portion 2 and the thin portion 3.

This deformed cross-section copper alloy sheet 1 has a composition composed of Zr: 0.05 to 0.2%, Cr: 0.2 to 0.4% by mass, and the balance being Cu and inevitable impurities.
Cr is an alloy element that precipitates in the copper matrix and improves strength by subjecting the copper alloy to solution treatment and then aging treatment. If the Cr content is less than 0.2% by mass, the effect of precipitation is insufficient, and if it exceeds 0.4% by mass, the effect of improving the strength cannot be obtained.
Zr is an alloy element that precipitates in the copper matrix phase by aging treatment after solution treatment of the copper alloy, thereby improving strength and heat resistance. The content of Zr affects the amount and size of the formed precipitated particles and changes the balance between conductivity and strength, but by containing 0.05 to 0.2% by mass, Both conductivity and strength can be balanced in a high dimension. If the content of Zr is less than 0.05% by mass, the effect due to the precipitation action is insufficient, and the stress relaxation resistance also decreases, and if it exceeds 0.2% by mass, the shape of the Cu—Zr precipitate tends to be coarse. Further, the effect of improving the strength cannot be obtained, which causes a decrease in bending workability.

Moreover, this irregular cross-section copper alloy plate 1 may further contain Si: 0.005 to 0.03% by mass.
When Si is added together with Zr, the overall strength is further improved. If the Si content is less than 0.005% by mass, the effect is not sufficient, and if it exceeds 0.03% by mass, the conductivity is lowered and the bending workability is adversely affected.

Further, the modified cross-section copper alloy plate 1, BadWay direction of bending workability _{(R / t) R 2,} GoodWay direction of bending workability (R / t) in the case of the _{R 1,} R 2 / _{R 1} Is 0.8 to 1.7. The bending in the BadWay direction is bending with the LD (rolling direction) as the bending axis, and the bending in the GoodWay direction is bending with TD (the direction perpendicular to the rolling direction and the plate thickness direction) as the bending axis. The bending workability is represented by the ratio (R / t) between the minimum bending radius R and the thickness t where no cracks are generated in the 90 ° W bending test according to JIS H3110.
When R ₂ / R _1, which is the ratio of the bending workability R _{2 in} the BadWay direction and the bending workability R _{1 in the} GoodWay direction, is less than 0.8 or exceeds 1.7, the anisotropy of the bending workability In particular, it often causes troubles in stamping and bending with a press.
Furthermore, this odd-shaped cross-section copper alloy plate 1 measures the orientation of all pixels within the measurement area of the surface of the thin portion by the EBSD method using a scanning electron microscope with a backscattered electron diffraction image system, GOS1, the average value of the average orientation difference between all the pixels in the crystal grains in all the crystal grains when the boundary where the orientation difference is 5 ° or more is regarded as the crystal grain boundary, within the measurement area of the surface of the thick part The average orientation difference between all pixels in the crystal grains in all the crystal grains when measuring the orientation of all the pixels and considering the boundary where the orientation difference between adjacent pixels is 5 ° or more as the grain boundary When the value is GOS2, GOS1 / GOS2 is 0.9 to 1.4.
If GOS1 / GOS2 is less than 0.9 or exceeds 1.4, it cannot have excellent stress relaxation resistance.

Next, the manufacturing method of the irregular cross-section copper alloy plate of this invention is demonstrated.
A plate-shaped copper alloy material 10 having the above composition is prepared, and the plate-shaped copper alloy material 10 after cold rolling is subjected to a deformed rolling process, a finish rolling process, a straightening process, and an aging process in this order, and a deformed cross section. The copper alloy plate 1 is manufactured.
In the profile rolling process, a flat plate-shaped die 22 having a concavo-convex surface to be a molding surface 21 as shown in FIGS. 2 and 3, and the die 22 is reciprocated along the molding surface 21 so as to face the molding surface 21. The plate-shaped copper alloy material 10 is cold-shaped and deformed by the rolling roll 23 to obtain a rough deformed cross-section copper alloy plate 11 in which the thick and thin portions 12 and 13 are arranged in the width direction. . In the illustrated example, the forming surface 21 of the die 22 is formed with a recess 25 for forming the thick portion 12 between the two protrusions 24 for forming the thin portion 13, and the rough deformed section copper alloy plate 11. The thick and thin portions 13 are disposed on both sides of the thick and thick portion 12, and the inclined portion 14 having a predetermined rising inclination angle is formed between the rough and thick portions 12 and 13 (see FIG. 1). .
In this profile rolling process, when the elongation in the width direction of the flat copper alloy material 10 is W ₁ (%) and the elongation in the rolling process direction is W ₂ (%), W ₁ / W ₂ is 1.4 to Carry out so that 2.3. Width direction of elongation _W 1 (%) is a flat copper difference width Wb of crude modified cross-section copper alloy sheet 11 to the width Wa of the alloy material 10 was expressed as a percentage (Wb-Wa) / Wa, rolling Elongation W ₂ (%) in the direction is (Lb−La) / La, in which the difference in length Lb of the rough deformed cross-section copper alloy plate 10 with respect to the length La of the flat copper alloy material 10 is expressed as a percentage.
When W ₁ / W ₂ is less than 1.4, R ₂ / R ₁ exceeds 1.7 and the tolerance (variation) in dimensional accuracy tends to deteriorate, and when W ₁ / W ₂ exceeds 2.3, The rolled structure is easily formed in a fiber shape in the rolling direction, and R ₂ / R ₁ is less than 0.8, and the anisotropy of bending workability is increased.
Moreover, in this profile rolling process, the average feed speed of the rough deformed section copper alloy plate 11 after the deformed rolling process is A (mm / min), and the thickness of the rough thin portion 13 of the rough deformed section copper alloy plate 11 is T ( mm), when the reciprocating rotation speed of the rolling roll 23 is B (times / minute), (A / B) / T is carried out at 1.5 to 70. When (A / B) / T is less than 1.5 or exceeds 70, the tolerance (variation) in the dimensional accuracy of the thick portion 2 and the thin portion 3 of the deformed cross-section copper alloy plate 1 to be formed increases. The average feed rate is an average value of feed rates per unit time in irregularly shaped cross-section machining that is intermittently fed.

  Next, as shown in the order of the arrows in FIG. 1, this rough deformed cross-section copper alloy plate 11 is subjected to a finish rolling process, and a finished deformed cross-section copper alloy plate 41 in which a thick portion 42 and a thin portion 43 are arranged in the width direction. To form. In the finish rolling process, the rough deformed cross-section copper alloy sheet 11 is cold-rolled and finish-rolled by a finish roll 33 including a step roll 31 and a flat roll 32 as shown in FIG. A plate 1 is obtained. The stepped roll 31 has a shape in which a small-diameter portion 35 for forming the thick-walled portion 42 is disposed between a pair of large-diameter portions 34 for forming the thin-walled portion 3. A thin section 43 is disposed on both sides, and a deformed cross-section copper alloy plate 41 is obtained in which the thick section 42 and the thin section 43 are inclined portions 44 having a predetermined rising inclination angle β (see FIG. 1). This finish rolling process is a rolling process that does not affect the anisotropy of the bending workability, has no distribution in the surface hardness, and has a finished irregular cross section having uniform physical properties in the thick part 42 and the thin part 43. In order to obtain the alloy plate 41, it is preferable to carry out cold rolling with a rolling roll 33 composed of a step roll 31 and a flat roll 32.

Next, in the stretch mechanism 82 as shown in FIG. 5, the bending in the length direction of the finished deformed cross-section copper alloy plate 41, preferably the actual measurement value of the bending amount per meter length is D1 (mm). Then, D1 is corrected so as to be 0.13 or less, and the deformed section copper alloy plate 1 is formed. The dimensions of the thick part 2, the thin part 3, and the inclined part 4 are the same as the dimensions of the thick part 42, the thin part 43, and the inclined part 44 of the finished deformed cross-section copper alloy plate 41.
In the straightening process, the finished deformed cross-section alloy plate 41 wound around the uncoiler 81 is fed out at a constant speed, and a predetermined tension is applied to the drawn finished deformed cross-section alloy plate E to obtain the desired deformed cross-section copper alloy plate 1. And a recoiler 83 that winds the deformed cross-section strip 1 that has passed through the stretch mechanism 82 at a constant speed. In this case, between the uncoiler 81 and the stretch mechanism 82, and between the stretch mechanism 82 and the recoiler 83, the finished deformed cross-section alloy plate E or the deformed cross-section alloy plate 1 has the slack portions Es and Gs for tension adjustment, respectively. It is preferably supported in the formed state.
The stretch mechanism 82 holds the finished deformed cross-section alloy plate E by the chuck 84 at two positions spaced apart in the length direction, fixes one end of the chuck 84, and moves the other end to move the finished deformed cross-section alloy plate. A predetermined tension (tensile amount) is applied to E to obtain a final deformed cross-section copper alloy plate 1. The relationship between tension (tensile amount) and strain (%) at this time is strain = tensile amount / interval of chuck before tension = elastic strain + plastic strain, and plastic strain can be obtained by strain-elastic strain. . By adjusting the stretch mechanism 82 so that the plastic strain is 0.05% to 1.0%, the deformed cross-section alloy plate 1 having excellent stress relaxation resistance is obtained.
When this plastic strain is less than 0.05%, GOS1 / GOS2 exceeds 1.4, and when the plastic strain exceeds 1.0%, GOS1 / GOS2 is less than 0.9, both of which have a reduced stress relaxation resistance. To do.

Next, an aging treatment is performed at 300 to 500 ° C. for 2 to 10 hours, for example. This aging treatment is not performed at the stage of producing the flat copper alloy material 10 but can be performed after the deforming process, thereby adjusting the precipitation state of the precipitated particles in the thick portion 2 and the thin portion 3 respectively. Further, it is possible to adjust the properties such as the tensile strength and conductivity of the thick portion 2 and the thin portion 3 within a predetermined range, and in order to enhance this effect, it is preferable to carry out after the finish rolling.
By the above manufacturing method, the deformed cross-section copper alloy sheet 1 having little bending anisotropy and excellent stress relaxation resistance can be obtained.

An ingot of a Cu—Cr—Zr-based copper alloy having the alloy composition shown in Table 1 is hot-rolled and cold-rolled to produce a copper alloy plate having a thickness of 2.3 mm and a width of 600 mm, and is thickened by a slitter line. A copper alloy plate having a thickness of 2.3 mm and a width of 45 mm was produced. This copper alloy sheet was sandwiched between a reciprocating rolling roll and a die forming surface at W ₁ / W ₂ , (A / B) / T shown in Table 1, and then subjected to irregular rolling copper. Alloy plates were produced continuously.

Next, a stepped roll in which a small diameter roll part for forming a thick part and a large diameter roll part for forming a thin part are formed side by side in the axial direction of these irregular cross-section copper alloy plates, and a radius Is sandwiched between a finishing roll consisting of a flat roll made constant along the axial direction and then subjected to continuous rolling, followed by correction under the conditions shown in Table 1, and further at 400 ° C. for 3 hours. The thick part has a width of 25 mm, the thin part has a width of 40 mm, the thick part has a thickness of 1.5 mm, the thin part has a thickness of 0.65 mm, and the thick part has a rising slope. The profile cross-section copper alloy plates of Examples 1 to 8 and Comparative Examples 1 to 5 having the shape shown in FIG. 1 and having thin portions on both sides of the thick portion are continuously formed at an angle β of 10 ° (80 ° from the horizontal plane) Produced.
In the straightening process (stretch mechanism), basically one end of the deformed cross-section copper alloy plate is fixed and the other end is moved to give a predetermined tension (tensile amount). The relationship of strain (%) is represented by strain = tensile amount / interval of chuck before tension = elastic strain + plastic strain, and the plastic strain can be determined by strain−elastic strain. In this example, the plastic strain was obtained by changing the tension (tensile amount) by setting the interval between the chucks 84 of the stretch mechanism 82 to 6000 mm. In this case, the elastic strain of the deformed cross-section copper alloy plate was set to 0.3% from the stress-strain curve.
The ratio of the bending workability R ₂ in the BadWay direction to the bending workability R _{1 in} the GoodWay direction, and the thin wall portion measured by the EBSD method using a scanning electron microscope with a backscattered electron diffraction image system. The average value of the average orientation difference between all the pixels in the crystal grains (GOS1) and the average value of the average orientation difference between all the pixels in the crystal grains of all the thick-walled grains (GOS2) The ratio of the tensile strength between the thick part and the thin part, the ratio of the Vickers hardness between the thick part and the thin part, and the stress relaxation resistance were obtained, and the dimensional tolerance of the thickness between the thick part and the thin part was measured.

BadWay direction of bending workability _{R 2} are cut plate material width 10 mm × length 60 mm, as 0.025mm unit of the bending R = 0~0.4mm, BW: bending 90 ° W of (BadWay rolling vertically) Then, the presence or absence of cracks in the bent portion was observed with a 50 × optical microscope, and the ratio between the minimum bending radius R at which no cracks occurred and the thickness t of the copper alloy plate was evaluated as R / t.
GoodWay bending workability R ₁ is obtained by cutting a plate material into a width of 10 mm × length of 60 mm, and performing 90 ° W bending of GW (GoodWay: rolling direction) as a unit of 0.025 mm of bending R = 0 to 0.4 mm, The presence or absence of cracks in the bent portion was observed with a 50 × optical microscope, and the ratio of the minimum bending radius R at which no crack occurred and the thickness t of the copper alloy plate was evaluated as R / t. In each case, a plurality of thick portions and thin portions were cut out and evaluated, and the average value was obtained.
GOS1 and GOS2 were obtained as follows.
As a pretreatment, a 10 mm × 10 mm sample was immersed in 10% sulfuric acid for 10 minutes, washed with water and sprinkled with air blow, and the sprinkled sample was accelerating with a flat milling (ion milling) device manufactured by Hitachi High-Technologies Corporation at an acceleration voltage of 5 kV. The surface treatment was performed at an incident angle of 5 ° and an irradiation time of 1 hour.
Next, the sample surface was observed with a scanning electron microscope S-3400N manufactured by Hitachi High-Technologies Corporation equipped with an EBSD system manufactured by TSL. The observation conditions were an acceleration voltage of 25 kV and a measurement area of 150 μm × 150 μm.
From the observation results, the average value of the average orientation difference between all the pixels in the crystal grains in all the crystal grains was obtained under the following conditions.
At a step size of 0.5 μm, the orientation of all pixels within the measurement area range was measured, and a boundary where the orientation difference between adjacent pixels was 5 ° or more was regarded as a crystal grain boundary. Next, with respect to all the individual crystal grains surrounded by the crystal grain boundary, the average value of the orientation difference (GOS: Grain Orientation Spread) between all the pixels in the crystal grain is calculated by the formula 1, and all of them are calculated. The average value of the values was defined as the average orientation difference between all the pixels in the crystal grains. In addition, what connected 2 pixels or more was made into the crystal grain.

In the above formula, i and j indicate the numbers of pixels in the crystal grains.
n indicates the number of pixels in the crystal grains.
α _ij represents the difference in orientation between pixels i and j.
Regarding this GOS, the GOS of the thin-walled portion was GOS1, and the GOS of the thick-walled portion was GOS2.
The stress relaxation resistance was measured by the cantilever method. A strip-shaped test piece having a width of 10 mm parallel to the rolling direction is cut out, one end thereof is fixed to a rigid test table, and a deflection amount of d (= 2 mm) is given to the span length L of the test piece. It was. At this time, L was determined so that a surface stress corresponding to 80% of the material yield strength was applied to the material. This was taken out after being held in an oven at 180 ° C. for 1000 hours, and the permanent strain δ when the deflection amount d was removed was measured to calculate the stress relaxation rate (RS) by RS = (δ / d) × 100, The stress relaxation resistance was determined with the residual stress rate (%) = 100−RS.
The tensile strength was measured with a JIS No. 5 test piece.
The measurement of Vickers hardness was performed by applying a weight of 4.9 N (0.5 kgf) with a micro Vickers hardness tester.
These results are shown in Table 2.

  From these measurement results, the deformed cross-section copper alloy plate produced by the production method of the present invention has less bending anisotropy, superior stress relaxation resistance, and a formed variant as compared with the comparative example. It can be seen that the tolerance (variation) of the dimensional accuracy of the part is small. The stress relaxation resistance is 85% or more. In addition, the tolerance of dimensional accuracy was as small as ± 0.005 to ± 0.010 mm, compared with ± 0.025 mm or more in the comparative example.

  As mentioned above, although the manufacturing method of embodiment of this invention was demonstrated, this invention is not limited to this description, A various change can be added in the range which does not deviate from the meaning of this invention.

DESCRIPTION OF SYMBOLS 1 Modified cross-section copper alloy plate 2 Thick part 3 Thin part 4 Inclined part 10 Flat copper alloy material 11 Roughly irregular cross-sectional copper alloy plate 12 Coarse thick part 13 Coarse thin part 14 Inclined part 21 Forming surface 22 Die 23 Rolling roll 31 Step roll 32 Flat roll 33 Finishing roll 82 Stretch mechanism 81 Uncoiler 83 Recoiler 84 Chuck

Claims (4)

It is a modified cross-section copper alloy plate in which a thick part and a thin part are arranged in the width direction, and is Zr in mass%: 0.05 to 0.2%, Cr: 0.2 to 0.4%, and the balance is Cu With regard to bending workability, which is a ratio (R / t) between a minimum bending radius R and a sheet thickness t, which has a composition consisting of inevitable impurities and does not generate cracks in a 90 ° W bending test according to JIS H3110 R ₂ / R ₁ is 0.8 to 1.7 when the bending workability (R / t) in the direction is R ₂ and the bending workability (R / t) in the GoodWay direction is R ₁ , Measure the azimuth of all pixels within the measurement area of the surface of the thin part by EBSD method using a scanning electron microscope with a scattered electron diffraction image system, and determine the boundary where the azimuth difference between adjacent pixels is 5 ° or more. All grains within all grains when considered as grain boundaries. The average value of the average orientation difference between cells is GOS1, the orientation of all pixels within the measurement area of the surface of the thick part is measured, and the boundary where the orientation difference between adjacent pixels is 5 ° or more is defined as a grain boundary. Bending process characterized in that GOS1 / GOS2 is 0.9 to 1.4, where GOS2 is the average value of the average orientation difference between all the pixels in the crystal grains in all the crystal grains -Shaped cross-section copper alloy sheet with less stress anisotropy and excellent stress relaxation resistance.   The deformed cross-section copper alloy sheet according to claim 1, further comprising Si: 0.005 to 0.03% by mass, and having low bending anisotropy and excellent stress relaxation resistance. When manufacturing the deformed cross-section copper alloy sheet by performing the deformed rolling process, finish rolling process, straightening process, and aging treatment in this order on the flat copper alloy material after cold rolling, the deformed rolling process is performed. The plate-like copper alloy material is sandwiched between the reciprocating rolling roll and the die forming surface and continuously rolled, and the elongation in the width direction is W ₁ (%) and the elongation in the rolling direction is W ₂ (% ), W ₁ / W ₂ is carried out at 1.4 to 2.3, and the straightening process is performed so that the plastic strain of the deformed cross-section copper alloy plate is 0.05% to 1.0%. The method for producing a deformed cross-section copper alloy sheet according to claim 1 or 2, wherein the anisotropy of bending is small and the stress relaxation resistance is excellent. In the deformed rolling process, the average feed rate of the deformed section copper alloy sheet after the deformed rolling process is A (mm / min), the thickness of the thin section of the deformed section copper alloy sheet is T (mm), The anisotropy of bending work according to claim 3, wherein (A / B) / T is carried out at 1.5 to 70 when the reciprocating rotation is B (times / minute). A method for producing a modified cross-section copper alloy sheet having excellent stress relaxation resistance.

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