JP2015034336A - Copper alloy sheet material and production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper alloy sheet material having high conductivity and high 0.2% proof stress and small residual stress, and a production method thereof.SOLUTION: There is provided the copper alloy sheet material containing Ni:1.5 to 7.0 mass%, Si:0.1 to 1.9 mass% and 0.000 to 2.000 mass% of element selected from among Mg:0.00 to 0.20 mass%, Sn:0.00 to 1.50 mass%, Zn:0.0 to 1.5 mass%, Cr:0.000 to 0.500 mass%, Mn:0.00 to 0.50 mass%, Ag:0.000 to 0.300 mass%, Co:0.00 to 2.00 mass%, and the balance Cu with inevitable impurities, and having a 0.2% proof stress of 900 MPa or more. In a sheet thickness-direction distribution of residual stress in the cross section vertical to the sheet width direction of the copper alloy sheet material and a sheet thickness-direction distribution of residual stress in the cross section vertical to the rolling direction of the copper alloy sheet material, an absolute value of difference between a maximum value and a minimum value of a residual stress of each of the cross section is 80 MPa or less.

Description

  The present invention relates to a high-strength copper alloy sheet material used for electrical and electronic equipment materials such as lead frames, connectors, and spring materials, and a method for manufacturing the same.

  As electronic devices such as mobile phones, portable audio players, and digital cameras are becoming smaller and more multifunctional, there is a need for lighter and multilayered boards mounted on them. Further, parts to be mounted are required to be further reduced in weight and size.

  Conventionally, solid solution strengthened alloys such as phosphor bronze and brass have been used for components such as connectors and relays. However, with the miniaturization of parts, the use of precipitation-strengthened alloys is increasing as a high-strength material that can satisfy the required strength even if it is thin and small. Among precipitation-strengthened alloys, Cu—Ni—Si alloys (corson alloys) that have good workability while having relatively high electrical conductivity and strength are female terminals and CPUs for connectors that require springiness. Widely used for sockets. Various alloy materials have been proposed for further improvement in strength and workability (for example, Patent Documents 1 to 3).

Patent Document 1 proposes a high-strength copper alloy material excellent in sag resistance, which contains a composite phase of Cu and Ag (CuAg phase) and Ni ₂ Si particles. In Patent Documents 2 and 3, the conditions for cold working and temper annealing are specified, and the residual stress on the surface is reduced, so that lead deformation of the lead frame is less likely to occur, and the stress relief annealing after press working is performed. A copper alloy sheet or strip having a short work time and excellent workability has been proposed.

JP 2006-291271 A JP 2010-7171 A JP 2011-38126 A

  However, since the conventional copper alloy sheet has a 0.2% proof stress of 900 MPa or less when the conductivity is 30% IACS or more, the camera AF (autofocus) used for mobile devices such as mobile phones and notebook computers is used. ) Insufficient strength for spring materials used in suspensions for magnetic heads of modules and hard disk drives. Further, when the 0.2% proof stress exceeded 900 MPa, the conductivity was 20% IACS or less, and the conductivity of the electronic component was low. Furthermore, with thin sheet materials with a thickness of 0.1 mm or less, it becomes difficult to suppress the residual stress caused by cold working, and if etching or pressing is performed on the plate material after temper annealing, it is caused by the residual stress. As a result, there is a problem that deformation such as warpage occurs. In the invention described in Patent Document 2 or Patent Document 3, residual stress is not sufficiently suppressed in cold rolling before strain relief annealing performed in the final stage. Therefore, in the strain relief annealing, in order to sufficiently remove the residual stress, it is necessary to increase the holding temperature, and there is a problem in that the strength is unavoidable.

  The present invention has been made in view of the above-described problems, and provides a copper alloy sheet material having high conductivity and 0.2% proof stress, low residual stress, and excellent workability, and a method for producing the same. Objective.

  In order to achieve the above object, a copper alloy sheet according to the present invention contains Ni: 1.5 to 7.0 mass%, Si: 0.1 to 1.9 mass%, and Mg: 0.00 to 0.20% by mass, Sn: 0.00-1.50% by mass, Zn: 0.0-1.5% by mass, Cr: 0.000-0.500% by mass, Mn: 0.00-0. 50% by mass, Ag: 0.000 to 0.300% by mass, Co: 0.000 to 2.00% by mass of an element selected from 0.000 to 2.00% by mass, and the balance from Cu and inevitable impurities A copper alloy sheet material having a 0.2% proof stress of 900 MPa or more, a residual stress distribution in the sheet thickness direction of a cross section perpendicular to the sheet width direction of the copper alloy sheet material, and a direction perpendicular to the rolling direction of the copper alloy sheet material In the residual stress distribution in the thickness direction of various sections, the maximum and minimum values of residual stress in each section The absolute value of the difference is equal to or less than 80 MPa.

  The copper alloy sheet according to the present invention further includes Mg: 0.01-0.20% by mass, Sn: 0.05-1.50% by mass, Zn: 0.2-1.5% by mass, Cr: 0. 0.005 to 0.500 mass%, Mn: 0.01 to 0.50 mass%, Ag: 0.005 to 0.300 mass%, Co: 0.05 to 2.00 mass%, at least one kind Is preferably contained in a total amount of 0.005 to 2.000 mass%.

  The copper alloy sheet according to the present invention preferably has an average crystal grain size of more than 0.1 μm and 50 μm or less.

  The copper alloy sheet according to the present invention preferably has a thickness of 5 μm or more and 80 μm or less.

  The method for producing a copper alloy sheet according to the present invention includes casting, homogenizing heat treatment, hot working, face cutting, first cold working, solution heat treatment, aging treatment, second cold working and temper annealing. The treatment process is performed in this order, the treatment temperature in the aging treatment is 400 to 700 ° C., the treatment time is 5 seconds to 20 hours, the work roll diameter in the second cold working is 150 mm or less, The surface roughness Ra is 0.5 μm or less, the rolling speed is 300 m / min or less, the processing rate per pass is 3 to 20%, and the total processing rate is 20 to 90%, and the processing temperature in the temper annealing. Is 200 to 450 ° C., and the treatment time is 30 minutes to 5 hours.

  The copper alloy sheet of the present invention has the characteristics that 0.2% proof stress is 900 MPa or more and conductivity is 30% IACS or more. In addition, the residual stress distribution in the plate thickness direction of the cross section perpendicular to the plate width direction of the copper alloy plate material and the residual stress distribution in the plate thickness direction of the cross section perpendicular to the rolling direction of the copper alloy plate material Since the absolute value of the difference between the maximum value and the minimum value is 80 MPa or less, it is difficult for defects such as warpage to occur when a copper alloy sheet is processed. That is, the copper alloy sheet of the present invention is excellent in workability. Further, in the method for producing a copper alloy sheet according to the present invention, the residual stress distribution in the thickness direction of the cross section perpendicular to the width direction of the copper alloy sheet, and the residual in the thickness direction of the cross section perpendicular to the rolling direction of the copper alloy sheet. In the stress distribution, a copper alloy plate material in which the absolute value of the difference between the maximum value and the minimum value of the residual stress in each cross section is 80 MPa or less can be suitably provided.

It is a figure for demonstrating the cross section of the copper alloy board | plate material which concerns on embodiment of this invention. (A) is the elements on larger scale of the cross section perpendicular | vertical to the board width direction of the copper alloy board | plate material in FIG. (B) is the elements on larger scale of the cross section perpendicular | vertical to the rolling direction of the copper alloy board | plate material in FIG.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as the present embodiment) will be specifically described. In the present invention, the copper alloy plate means a copper alloy material processed into a specific shape such as a plate, strip, or foil by a rolling process. In the present application, these are collectively referred to as a copper alloy sheet. Further, in the present application, “mass%” is also simply referred to as “%”.

(1) Composition of copper alloy sheet material Ni reacts with Si to form a Ni ₂ Si compound. By aging precipitation of the Ni ₂ Si compound, the strength of the copper alloy sheet can be improved and the electrical conductivity can be increased. The content of Ni in the copper alloy sheet according to the present embodiment is 1.5 to 7.0%. More preferably, it is 2.0 to 5.0%. When the Ni content is less than 1.5%, the precipitation hardening amount due to the Ni—Si precipitate is small and the strength is insufficient. On the other hand, if the Ni content exceeds 7.0%, grain boundary reaction type precipitation occurs during the heat treatment, and the amount of coarse crystallized material increases excessively, which may reduce the strength.

Si reacts with Ni to form a Ni ₂ Si compound. By aging precipitation of the Ni ₂ Si compound, the strength of the copper alloy sheet can be improved and the electrical conductivity can be increased. The Si content in the copper alloy sheet of the present embodiment is 0.1 to 1.9%. More preferably, it is 0.35 to 1.7%. If the Si content is less than 0.1%, the strength improvement by the aging treatment is insufficient. On the other hand, if the Si content exceeds 1.9%, the same problem as in the case where the Ni content is large is caused, and the conductivity is lowered.

  Mg exists in the form of a solid solution in the matrix phase, and has the effect of suppressing the formation of grain boundary reaction type precipitation and improving the stress relaxation characteristics. The Mg content in the copper alloy sheet of the present embodiment is preferably 0.01 to 0.20%, more preferably 0.05 to 0.15%. If the Mg content is less than 0.01%, the effect does not sufficiently appear, and if it exceeds 0.20%, the bending workability deteriorates.

  Sn exists in a solid solution form in the parent phase, and suppresses the formation of grain boundary reaction type precipitation and improves the stress relaxation characteristics. The Sn content in the copper alloy sheet according to the present embodiment is preferably 0.05 to 1.50%, more preferably 0.1 to 0.7%. If the Sn content is less than 0.05%, the effect is not sufficiently exhibited, and if it exceeds 1.50%, the conductivity is significantly lowered.

  Zn is present in the form of a solid solution in the matrix and improves hot workability. The content of Zn in the copper alloy sheet according to the present embodiment is preferably 0.2 to 1.5%, more preferably 0.3 to 1.2%. If the Zn content is less than 0.2%, the effect cannot be sufficiently obtained, and if the Zn content exceeds 1.5%, the conductivity is lowered.

  Cr reacts with Si and Ni to form a Cr—Si compound and a Ni—Cr—Si compound. These intermetallic compounds suppress the movement of the grain boundary during the solution treatment to make the crystal grain size of the parent phase fine, and contribute to the suppression of the grain boundary reaction type precipitation. The content of Cr in the copper alloy sheet according to this embodiment is preferably 0.005 to 0.500%, and more preferably 0.05 to 0.3%. If the Cr content is less than 0.005%, the effect cannot be sufficiently obtained, and if it exceeds 0.500%, the bending workability deteriorates.

  Ag improves heat resistance and strength, and at the same time, prevents coarsening of crystal grains and improves bending workability. The Ag content in the copper alloy sheet according to the present embodiment is preferably 0.005 to 0.300%. If the Ag content is less than 0.005%, the effect cannot be sufficiently obtained. Further, even if the Ag content exceeds 0.300%, the properties are not adversely affected, but the cost is increased.

  Co, like Ni, has a function of forming a compound with Si and improving the strength. The Co content in the copper alloy sheet of the present embodiment is preferably 0.05 to 2.00%. If the Co content is less than 0.05%, the effect cannot be sufficiently obtained. On the other hand, if the Co content exceeds 2.00%, crystallization / precipitates that do not contribute to the strength exist after the solution treatment, and the bending workability deteriorates.

  Mn has an effect of improving hot workability, and it is effective to contain 0.01 to 0.50% by mass so as not to deteriorate the conductivity.

  When one or more of the above-mentioned Mg, Sn, Zn, Cr, Ag, Co, and Mn are contained, the total is determined in the range of 0.005 to 2.000% depending on the required characteristics. .

  In the copper alloy sheet according to the present embodiment, the S content is preferably less than 0.005%, and more preferably less than 0.002%. When the S content is 0.005% or more, the hot workability deteriorates.

(2) Physical properties of copper alloy sheet material The copper alloy sheet material of this embodiment is characterized by a small residual stress in the sheet material. Residual stress occurs as a result of non-uniform deformation due to heat treatment or cold working, and is widely distributed on the surface of the copper alloy plate (rolled material) and inside the plate. If the gradient of the residual stress distribution on the surface and inside of the rolled material is large, that is, if the difference between the maximum value and the minimum value of the residual stress is large, the residual stress is released when etching or pressing is performed, and warping, etc. Deformation tends to occur. Or, even if it does not appear as deformation at the time of processing, it becomes a plate material that may cause deformation during use. Therefore, it is necessary to control the residual stress in the copper alloy sheet material to be small.

  Therefore, in the present invention, the thickness direction (ND: Normal Direction) of each cross section of the cross section perpendicular to the rolling direction (RD; Rolling Direction) and the cross section perpendicular to the plate width direction (TD; Transverse Direction) of the copper alloy sheet material. In the residual stress distribution, the absolute value of the difference between the maximum value and the minimum value of the residual stress in each cross section is controlled to 80 MPa or less. More specifically, in the residual stress distribution in the thickness direction in the cross section perpendicular to the rolling direction (RD) of the copper alloy sheet material, the absolute value of the difference between the maximum value and the minimum value of the residual stress in the cross section is 80 MPa or less, and In the residual stress distribution in the plate thickness direction in the cross section perpendicular to the plate width direction (TD) of the copper alloy plate material, the absolute value of the difference between the maximum value and the minimum value of the residual stress in the cross section is 80 MPa or less.

  With reference to FIG. 1 and FIG. 2, the residual stress distribution in the cross section of the copper alloy sheet | seat material 1 of this embodiment is demonstrated. FIG. 1 is a view for explaining a cross section of a copper alloy sheet 1 of the present embodiment. FIG. 1 shows the residual stress distribution 2 in the thickness direction (ND) in the cross section perpendicular to the plate width direction (TD) of the copper alloy plate 1 and the thickness in the cross section perpendicular to the rolling direction (RD) of the copper alloy plate 1. The residual stress distribution 3 in the direction (ND) is shown. 2A is a partially enlarged view of a cross section perpendicular to the plate width direction (TD) of the copper alloy sheet 1 in FIG. 1, and FIG. 2B is a rolling direction of the copper alloy sheet 1 in FIG. It is the elements on larger scale of the cross section perpendicular | vertical to (RD).

  In FIG. 2A, a curve 2a indicates a value of residual stress in the rolling direction (RD), and an axis 2b indicates that the residual stress is zero. In the residual stress distribution 2 in the plate thickness direction (ND) in the cross section perpendicular to the plate width direction (TD), how the residual stress in the rolling direction (RD) is distributed with respect to the plate thickness in the cross section. Is shown. The value A means the absolute value of the difference between the maximum value and the minimum value of the residual stress in the rolling direction (RD). In FIG. 2B, a curve 3a indicates a value of residual stress in the plate width direction (TD), and an axis 3b indicates that the residual stress is zero. In the residual stress distribution 3 in the plate thickness direction (ND) in the cross section perpendicular to the rolling direction (RD), the distribution of the residual stress in the plate width direction (TD) with respect to the plate thickness in the cross section is shown. Show. The value B means the absolute value of the difference between the maximum value and the minimum value of the residual stress in the plate width direction (TD). In the residual stress distribution in each cross section, the absolute value of the difference between the maximum stress value (σmax) and the minimum stress value (σmin) is controlled to be 80 MPa or less (| σmax−σmin | ≦ 80 MPa). It is an invention. That is, A ≦ 80 MPa and B ≦ 80 MPa.

  As shown in FIGS. 2A and 2B, the positive (plus) value of the residual stress with respect to the shaft 2b and the shaft 3b is set as the tensile stress, and the negative (minus) value is set as the compressive stress. To do. In this way, the maximum value of residual stress is tensile stress, and the minimum value is compressive stress. That is, the control of the residual stress in the present invention corresponds to setting the difference (absolute value) between the “maximum value of tensile stress” and the “minimum value of compressive stress” within 80 MPa. The absolute value of the difference between the maximum value and the minimum value of the residual stress in the residual stress distribution in the thickness direction of each cross section is more preferably 50 MPa or less. The absolute value of the difference between the maximum value and the minimum value of the residual stress in the residual stress distribution in the plate thickness direction of each cross section is not particularly specified, but is 0 or more because it is an absolute value. In addition, the residual stress in this invention is the value measured based on the Truting-Read method.

  The copper alloy sheet of the present embodiment preferably has an average crystal grain size of more than 0.1 μm and 50 μm or less. More preferably, it is more than 0.1 μm and 25 μm or less. If the average crystal grain size is 0.1 μm or less, the workability deteriorates. When the average crystal grain size exceeds 50 μm, sufficient strength cannot be obtained, and the strength difference between the rolling vertical direction and the rolling parallel direction becomes large. The average crystal grain size in the present invention is a value measured based on JISH0501 (cutting method).

  The copper alloy sheet of this embodiment has a 0.2% yield strength (YS) of 900 MPa or more. Preferably it is 1000 MPa or more. The upper limit value of 0.2% proof stress YS is not particularly limited, but is practically about 1500 MPa. The 0.2% proof stress in the present invention is a value measured based on a tensile test using a normal tensile tester.

  The thickness of the copper alloy sheet according to the present embodiment can be appropriately adjusted according to the application, molding conditions, etc., but is preferably 5 μm to 80 μm. More preferably, it is 10-80 micrometers. When the thickness is less than 5 μm, the number of passes increases and the production efficiency deteriorates significantly in order to perform rolling so that the difference between the maximum value and the minimum value of the residual stress is 80 MPa or less. In addition, although the copper alloy plate material of this embodiment is a copper alloy plate material with a plate thickness of 80 μm or less in particular, it can be applied to a copper alloy plate material exceeding 80 μm. The present invention has technical significance in that it has a small residual stress and a high 0.2% proof stress even at a thin plate thickness.

  The copper alloy sheet having the above physical properties can be suitably used as an electrical / electronic equipment material that requires high strength. For example, a lead frame, a connector, or a spring material.

(3) Manufacturing method of copper alloy plate material The copper alloy plate material of the present embodiment is formed by casting, homogenizing heat treatment, hot working, surface cutting, first cold working, solution heat treatment to a copper alloy having a predetermined composition. , Aging treatment, second cold working and temper annealing are performed in this order. Hereinafter, the manufacturing method of the copper alloy sheet of this embodiment will be described in detail.

  First, in a casting process, after melting a copper alloy material having a predetermined composition, a copper alloy ingot is obtained by casting. In the homogenizing heat treatment step, the copper alloy ingot is held at 850 to 1000 ° C. for 0.5 to 6 hours for the purpose of homogenizing the alloy components and the structure. Thereafter, hot working is performed to obtain a desired plate thickness. In the hot working step, rolling is performed at 700 to 1000 ° C. The chamfering step is performed in order to remove the oxide film and the altered layer on the skin of the copper alloy sheet. This can be done by a generally known method.

  Subsequently, in the first cold working step, rolling is preferably performed so that the working rate is 80 to 99.99%. Thereafter, a solution heat treatment is performed in order to solution the material. In the solution heat treatment step, it is preferable to hold the temperature at 800 to 1000 ° C. for 3 seconds to 1 hour.

The aging treatment is a treatment for precipitating a precipitated phase such as Ni ₂ Si in the parent phase of the material that has become a supersaturated solid solution. The processing temperature in an aging treatment process is 400-700 degreeC. Preferably, it is 350-600 degreeC. If the treatment temperature is less than 400 ° C., it takes a long time to obtain a sufficient amount of Ni ₂ Si deposited, resulting in an increase in cost. Or the proof stress and the electrical conductivity are insufficient. On the other hand, when the processing temperature exceeds 700 ° C., coarse Ni ₂ Si is formed, so that sufficient proof stress cannot be obtained. The processing time is 5 seconds to 20 hours.

  Residual stress is generated in the second cold working step, and in order to prevent deterioration of dimensional accuracy in etching and press working, it is important to perform a process that suppresses variations in the residual stress distribution on the surface and inside as much as possible. The variation in the residual stress distribution in the second cold working step is the maximum value of the residual stress in each of the “cross section perpendicular to the sheet width direction” and “cross section perpendicular to the rolling direction” of the copper alloy sheet. And the minimum value.

  Here, the work roll diameter in the second cold working step is 150 mm or less. When the work roll diameter exceeds 150 mm, the deformation on the inner side of the copper alloy sheet increases, and the dispersion of the residual stress distribution within the sheet increases from the surface of the sheet. The surface roughness of the work roll is 0.5 μm or less in terms of arithmetic average roughness Ra, preferably 0.3 μm or less, and more preferably 0.1 μm or less. When the arithmetic average roughness Ra exceeds 0.5 μm, a difference occurs in the amount of deformation between the surface and the inside of the copper alloy sheet, and the dispersion of the residual stress distribution increases. No particular lower limit is set for the arithmetic average roughness Ra, but if it is too small, slip will occur between the roll and the plate, and the rolling control will become unstable. The rolling speed is 300 m / min or less, preferably 200 m / min. If the rolling speed exceeds 300 m / min, the variation in the residual stress distribution cannot be reduced. In particular, a lower limit is not set for the rolling speed, but if it is too low, the production efficiency will deteriorate. The processing rate per pass is 3 to 20%. When the processing rate per pass is less than 3% or the processing rate exceeds 20%, a large difference occurs in the amount of deformation between the surface and the inside, and the dispersion of the residual stress distribution increases. The total processing rate is 20 to 90%. In order to obtain sufficient strength, the total processing rate is preferably 20% or more, and more preferably 30% or more. More preferably, it is 50% or more. When the total processing rate exceeds 90%, the strength difference between the parallel direction and the vertical direction with respect to the rolling direction becomes large after the temper annealing step, and the degree of design freedom as a copper alloy sheet for electric / electronic parts decreases.

  In the second cold working step, it is preferable that the steepness indicating the degree of middle elongation, end elongation, and the like of the copper alloy sheet according to the present embodiment is 1.0% or less. It can be said that the shape of the copper alloy sheet having such a steepness is good.

  Finally, temper annealing is performed for the purpose of tempering the copper alloy sheet. The processing temperature in a temper annealing process is 200-450 degreeC. Preferably, it is 250-350 degreeC. When the treatment temperature is less than 200 ° C., the elongation, bending workability, and recovery of the spring limit value are insufficient, and the strength is insufficient. When the processing temperature exceeds 450 ° C., the strength is reduced. The treatment time is not particularly limited, but is, for example, 30 minutes to 5 hours.

  Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

  A copper alloy having the composition shown in Table 1 was melted and cast to obtain a copper alloy ingot. Thereafter, homogenization treatment, hot working, and chamfering were performed. Next, cold working was performed so that the processing rate was 95% or more, solution heat treatment was performed at 875 ° C. for 6 seconds, and aging treatment was performed at 475 ° C. for 2 hours. Next, cold working was performed under the conditions described in Table 2 (work roll diameter, work roll surface roughness, total working rate, maximum working rate per pass, rolling speed). And temper annealing was performed on the conditions (processing time, processing temperature) described in Table 2, and the copper alloy board | plate material of thickness 0.03mm was obtained.

  In addition, although the board | plate thickness of the copper alloy board | plate material showed the example of 0.03 mm (= 30 micrometers) in the present Example, this invention is 5-5 by adjusting a process condition and heat processing conditions within the range of an indication of this application. It was confirmed that it can be carried out with a plate thickness of 80 μm.

(Residual stress)
The residual stress in the plate thickness direction in the cross section perpendicular to the rolling direction (RD) and the cross section perpendicular to the plate width direction (TD) of the copper alloy sheet was measured by the following methods. First, the residual stress distribution in a cross section perpendicular to the plate width direction (TD) is obtained by cutting a test plate having a width of 20 mm × length of 100 mm from a copper alloy plate with the rolling direction (RD) as the “longitudinal direction”. While gradually removing the surface layer on one side of the test piece using an etching solution, the curvatures φ _x and φ _y in the longitudinal direction (x) and the width direction (y) of the remaining test piece at each depth are measured. This is repeated until the plate thickness is halved. The curvature is obtained by measuring the warpage of the specimen. The curvature of the test piece is considered as a part of the circumference, and the reciprocal of the radius corresponding to this circle is the curvature. The curvature can be easily obtained mathematically by measuring the length and height of the strings. Thereafter, the relationship between the etching depth a and the curvature is plotted in the figure, and the maximum value σ _xmax (a) and the minimum value σ _xmin (a) of the residual stress in the rolling direction (x) at the etching depth are measured by the following equations. To do. Further, the residual stress distribution in the cross section perpendicular to the rolling direction (RD) is also measured in the same manner using a test piece having the plate width direction (TD) as the “longitudinal direction”. This method is a well-known method called the “Truting-Read method”, and is described in, for example, the following references. Based on this method, the respective cross sections in the residual stress distribution in the plate thickness direction of the cross section perpendicular to the plate width direction of the copper alloy plate material and the residual stress distribution in the plate thickness direction of the cross section perpendicular to the rolling direction of the copper alloy plate material. The absolute value of the difference between the maximum and minimum values of residual stress was calculated. The results are shown in Table 2.
Reference: R.D. G. Truting, W.M. F. Read: J.M. App. Physics, 22 (1951) 130.

σ_x：長手方向における残留応力、Ｅ：ヤング率、ν：ポアソン比、ｈ：当比板厚、ａ：エッチング深さ、φ_x：長手方向における曲率、φ_y：幅方向における曲率

σ _x : residual stress in the longitudinal direction, E: Young's modulus, ν: Poisson's ratio, h: equivalent plate thickness, a: etching depth, φ _x : curvature in the longitudinal direction, φ _y : curvature in the width direction

(0.2% yield strength)
The 0.2% proof stress was obtained by measuring three test pieces of JIS Z 2201-13B cut out from the rolling parallel direction according to JIS Z 2241 and showing the average value. Table 2 shows the measurement results of 0.2% proof stress.

(conductivity)
The electrical conductivity was calculated by measuring the specific resistance by a four-terminal method in a constant temperature bath maintained at 20 ° C. (± 0.5 ° C.). In addition, the distance between terminals was 100 mm. Table 2 shows the measurement results of conductivity.

(Crystal grain size)
The crystal grain size was measured based on JIS H 0501 (cutting method). In all Examples, it was confirmed that the crystal grain size was in the range of more than 0.1 μm and 50 μm or less.

  As shown in Table 2, in Examples 1 to 20, the 0.2% proof stress is 900 MPa or more, the conductivity is 30% IACS or more, and the cross section perpendicular to the sheet width direction and the rolling direction In the residual stress distribution in the plate thickness direction of the vertical cross section, the absolute value of the difference between the maximum value and the minimum value of the residual stress is 80 MPa or less in each cross section. That is, it turned out that the copper alloy board | plate material of Examples 1-20 is excellent in workability with high intensity | strength. On the other hand, it was found that the copper alloy sheet materials of Comparative Examples 1 to 5, 12 to 19, and 32 to 39 were inferior in strength because the 0.2% proof stress was low. Moreover, it turned out that the copper alloy board | plate material of Comparative Examples 6-11, 20-31 is inferior to workability, since the difference of the maximum value and the minimum value of the residual stress in any or both directions is large. It was found that the copper alloy sheet materials of Comparative Examples 40 to 44 were inferior in strength and workability because the 0.2% proof stress was low and the difference between the maximum value and the minimum value of the residual stress was large.

1 Copper alloy sheet 2, 3 Residual stress distribution 2a, 3a Curve 2b, 3b Axis

Claims (5)

Ni: 1.5 to 7.0% by mass, Si: 0.1 to 1.9% by mass,
Mg: 0.00-0.20 mass%, Sn: 0.00-1.50 mass%, Zn: 0.0-1.5 mass%, Cr: 0.000-0.500 mass%, Mn: 0.000 to 2.000 mass%, Ag: 0.000 to 0.300 mass%, Co: 0.000 to 2.00 mass% of an element selected from 0.000 to 2.00 mass%, A copper alloy sheet made of the remaining Cu and inevitable impurities,
0.2% proof stress is 900 MPa or more,
In the residual stress distribution in the plate thickness direction of the cross section perpendicular to the plate width direction of the copper alloy plate material and the residual stress distribution in the plate thickness direction of the cross section perpendicular to the rolling direction of the copper alloy plate material, the residual stress of each cross section A copper alloy sheet characterized in that the absolute value of the difference between the maximum value and the minimum value is 80 MPa or less.   Furthermore, Mg: 0.01-0.20 mass%, Sn: 0.05-1.50 mass%, Zn: 0.2-1.5 mass%, Cr: 0.005-0.500 mass%, Mn: 0.01 to 0.50 mass%, Ag: 0.005 to 0.300 mass%, Co: 0.05 to 2.00 mass%, and at least one kind in a total amount of 0.005 to 2. It contains 000 mass%, The copper alloy board | plate material of Claim 1 characterized by the above-mentioned.   The copper alloy sheet according to claim 1 or 2, wherein the average crystal grain size is more than 0.1 µm and not more than 50 µm.   The copper alloy sheet according to any one of claims 1 to 3, wherein the thickness is 5 µm or more and 80 µm or less. It is a manufacturing method of the copper alloy sheet material according to any one of claims 1 to 4,
Apply in this order the process consisting of casting, homogenization heat treatment, hot working, face cutting, first cold work, solution heat treatment, aging treatment, second cold work and temper annealing,
The treatment temperature in the aging treatment is 400 to 700 ° C., the treatment time is 5 seconds to 20 hours,
The work roll diameter in the second cold working is 150 mm or less, the surface roughness Ra of the work roll is 0.5 μm or less, the rolling speed is 300 m / min or less, the working rate per pass is 3 to 20%, and The total processing rate is 20-90%,
A method for producing a copper alloy sheet material, wherein a treatment temperature in the temper annealing is 200 to 450 ° C. and a treatment time is 30 minutes to 5 hours.

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