JP2014051708A - Copper base alloy for electrical and electronic parts and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper base alloy for electrical and electronic parts satisfying specification properties of ESH individual of C1940, maintaining heat resistance and having low magnetism, and to provide its manufacturing method.SOLUTION: A copper base alloy for electrical and electronic parts contains Fe of 2.1 mass% to 2.6 mass%, P of 0.015 mass% to 0.15 mass%, Zn of 0.05 mass% to 0.2 mass% and the balance Cu with inevitable impurities, and has a tensile strength of 505 MPa to 590 MPa, a Vickers hardness of 145 Hv to 170 Hv, a conductivity of 60% IACS or more and a maximum permeability of 1.045 to 1.060.

Description

  The present invention relates to a copper-based alloy for electrical / electronic components suitable for electrical / electronic components such as lead frames, and a method for producing the same.

  Some semiconductor components used in electric / electronic devices have a package structure using a lead frame as an electric / electronic component. In recent years, lead frames have been increased in the number of pins and book thickness in accordance with the demand for downsizing of semiconductor components. Under such circumstances, higher strength and electrical conductivity are required for the lead frame material. As a copper base alloy for electric and electronic parts used for a lead frame, CSH (Extra Spring Hard) classification of C1940 (JIS 3100: 2006) can be cited as a material that satisfies the required characteristics relatively well. C1940 is a copper-based alloy to which 2.1 mass% or more and 2.6 mass% or less of Fe, 0.015 mass% or more and 0.15 mass% or less of P, 0.05 mass% or more and 0.2 mass% or less of Zn is added, The ESH quality is a work hardened so as to exceed the SH (Spring Hard) quality.

  This copper-based alloy for electric / electronic parts is required to have the above-described strength and electrical conductivity, as well as heat resistance. The lead frame is formed by punching or etching a copper base alloy for electric / electronic parts, and the punching process accumulates strain in the copper base alloy for electric / electronic parts. The strain accumulated in the copper-based alloy for electrical / electronic parts is released by etching, which causes pin deformation. Therefore, annealing is performed to remove strain accumulated in the copper-based alloy for electric / electronic parts by punching. In this annealing, the copper base alloy for electric / electronic parts having low heat resistance is softened, which also causes pin deformation.

  Therefore, the copper base alloy for electric / electronic parts is required to have heat resistance that does not soften by annealing to remove the strain accumulated in the copper base alloy for electric / electronic parts. Control of heat resistance of a copper base alloy (hereinafter referred to as Cu-Fe alloy) containing Fe containing C1940 as a main additive element is considered to be effective in controlling Fe precipitates. It is described in the literature. For example, in Patent Document 1, if the volume fraction in the alloy of Fe particles having a diameter of 40 nm or less among the precipitated Fe particles is 0.2% or more, the strength is reduced even if heating for strain removal is performed. It is described that a Cu—Fe-based alloy material for lead frames having a relatively low heat resistance can be provided.

Japanese Patent Laid-Open No. 11-80862 JP 2011-208271 A Japanese Patent Laid-Open No. 7-18355 JP 7-62504 A JP 2010-95749 A

Genjiro Mima, 3 others, “Softening behavior of annealed copper-2.3% iron alloy after aging”, Journal of the Japan Institute of Metals, 1969, Vol. 33, No. 5, p. . 521-526 Hori Shigetoku et al., Journal of Copper Technology Research, 1970, Vol. 9, p. 201

  As described above, control of Fe precipitates is important for controlling the heat resistance of Cu-Fe alloys, but there are two forms of Fe precipitates: non-magnetic γ-Fe and ferromagnetic α-Fe. Are known to have different effects on heat resistance.

  By the way, in applications where high-frequency signals are transmitted or applications where the operating frequency is high, for example, in memory ICs, when the frequency of transmission signals, etc. increases, impedance increases with increasing magnetism. To affect. Therefore, it is not preferable to disperse the ferromagnetic α-Fe in the Cu—Fe alloy in applications where high frequency signals are transmitted.

  However, it is necessary to disperse Fe precipitates in the Cu-Fe alloy in order to control heat resistance. Therefore, it is ideal that only the γ-Fe can ensure the heat resistance of the Cu—Fe alloy, but it is known that γ-Fe is transformed into α-Fe by processing at room temperature (for example, Non-Patent Document 1). Reference), it is very difficult to control the heat resistance only with γ-Fe for ESH categorization that has obtained high strength by work hardening.

  Therefore, how to obtain heat resistance by reducing α-Fe dispersed in the Cu—Fe alloy is an issue. In patent document 1, although the diameter and volume fraction of Fe precipitate are prescribed | regulated, it is not mentioned at all about whether the form of Fe precipitate is (alpha) -Fe or (gamma) -Fe.

  Accordingly, an object of the present invention is to provide a copper-based alloy for electric and electronic parts having lower magnetic properties while satisfying the standard characteristics of C1940 according to ESH quality and maintaining heat resistance, and a method for producing the same.

  The present invention devised to achieve this object is Fe of 2.1 mass% or more and 2.6 mass% or less, P of 0.015 mass% or more and 0.15 mass% or less, 0.05 mass% or more and 0.2 mass% or less. Zn, with the balance being Cu and unavoidable impurities, tensile strength of 505 MPa to 590 MPa or less, Vickers hardness of 145 Hv to 170 Hv, conductivity of 60% IACS or more, and maximum magnetic permeability of 1.045. It is a copper-based alloy for electric / electronic parts having a value of 1.060 or less.

The saturation magnetization is preferably 26.5 emu / cm ³ or more and 30.5 emu / cm ³ or less.

  The residual hardness after the heat resistance test heated at 450 ° C. for 5 minutes is preferably 90% or more.

  Further, the present invention contains 2.1 mass% or more and 2.6 mass% or less of Fe, 0.015 mass% or more and 0.15 mass% or less of P, 0.05 mass% or more and 0.2 mass% or less of Zn, and the balance is To an ingot made of Cu and inevitable impurities, hot rolling, first cold rolling, first heat treatment, second cold rolling, second heat treatment, third cold rolling, and third In the copper-based alloy for electric / electronic parts manufactured by sequentially performing the heat treatment, the second heat treatment is performed at 1 ° C./min to a desired temperature and at 1 ° C./min to a desired temperature. The third cold rolling is a copper-based alloy for electrical / electronic parts performed at a working degree of 70% to 80%.

  Further, the present invention contains 2.1 mass% or more and 2.6 mass% or less of Fe, 0.015 mass% or more and 0.15 mass% or less of P, 0.05 mass% or more and 0.2 mass% or less of Zn, and the balance is To an ingot made of Cu and inevitable impurities, hot rolling, first cold rolling, first heat treatment, second cold rolling, second heat treatment, third cold rolling, and third In the method for producing a copper-based alloy for electrical / electronic parts that is sequentially subjected to heat treatment, the second heat treatment is performed by raising the temperature to a desired temperature at 1 ° C./min and lowering the temperature to a desired temperature at 1 ° C./min. The third cold rolling is a method for producing a copper-based alloy for electric / electronic parts performed at a working degree of 70% to 80%.

  ADVANTAGE OF THE INVENTION According to this invention, the copper base alloy for electrical and electronic components with lower magnetism and its manufacturing method can be provided, satisfy | filling the standard characteristic according to ESH quality of C1940, and maintaining heat resistance.

It is a figure which shows the magnetization measurement result in Example 1. FIG. It is the figure arranged paying attention to the relationship between saturation magnetization and hardness residual rate.

  Hereinafter, preferred embodiments of the present invention will be described.

The copper-based alloy for electrical / electronic parts according to the present embodiment includes 2.1 mass% or more and 2.6 mass% or less of Fe, 0.015 mass% or more and 0.15 mass% or less of P, 0.05 mass% or more and 0.2 mass% or less. % Zn or less, the balance consisting of Cu and inevitable impurities, tensile strength of 505 MPa to 590 MPa or less, Vickers hardness of 145 Hv to 170 Hv, conductivity of 60% IACS or more, maximum magnetic permeability of 1 0.045 or more and 1.060 or less. In addition to these characteristics, the saturation magnetization is preferably 26.5 emu / cm ³ or more and 30.5 emu / cm ³ or less, and the hardness remaining ratio after a heat resistance test heated at 450 ° C. for 5 minutes is preferably 90% or more. .

  The reasons for limiting the numerical values of each component constituting the copper-based alloy for electric / electronic parts will be described together with the reason for addition.

(1) About Fe, P, Zn These are standard components of C1940, and the range of numerical limitation conforms to this standard.

(2) Other element components In addition to the standard components of C1940, elements that cannot be mixed as impurities include Mg, Al, Si, Sn, Ti, Cr, Mn, Co, Ni, Zr, C, There is O. These are elements contained in raw materials, deoxidizers, and the like, and are elements that may be mixed during casting. If the total amount of these elements is 0.1 mass% or less, the copper-based alloy for electric / electronic parts is not adversely affected and is acceptable as an inevitable impurity.

  Next, the reason for limiting the numerical values of each characteristic of the copper-based alloy for electric / electronic parts will be described.

(1) Tensile strength, Vickers hardness, electrical conductivity Copper base alloys for electrical and electronic parts are improved according to the ESH quality of C1940 standardized in JISH3100: 2006 in Japan. As for the standard characteristics, the tensile strength is 505 MPa to 590 MPa, the Vickers hardness is 145 Hv to 170 Hv, the electrical conductivity is 60% IACS or more, and the numerical limit range conforms to this standard.

  The tensile strength is measured according to JISZ2241: 2011, the Vickers hardness is measured according to JISZ2244: 2009 from a cross section perpendicular to the rolling direction by embedding a test piece in a room temperature curable resin, and the conductivity is measured by the 4-terminal method. It calculates using the conversion formula (constant cross-sectional area method) described in JISH0505: 1975 from the electrical resistance measured using.

(2) Maximum magnetic permeability Magnetic permeability is a characteristic that affects the impedance of a high-frequency signal. For example, a skin effect is a phenomenon that occurs when a high-frequency current flows through a conductor. This is a phenomenon that the current concentrates on the surface of the conductor as the frequency of the current flowing through the conductor increases, and the effective area through which the current flows decreases and the AC resistance increases. The relationship between the frequency of the current flowing through this conductor and the skin depth is expressed by the following equation (1).

  Here, d is the skin depth (the depth at which the current becomes 1 / e of the surface current), ρ is the electrical resistance of the conductor, ω is the angular frequency (expressed by 2πf when the frequency is f), and μ is The magnetic permeability of the conductor. As can be seen from equation (1), when the magnetic permeability increases, the skin depth decreases, that is, the area through which current flows decreases. If the maximum magnetic permeability is in a numerically limited range, the skin effect can be reduced, and the copper-based alloy for electrical / electronic parts can be suitably used for applications that transmit high-frequency signals or that have a high operating frequency.

  The maximum magnetic permeability is the maximum value among values obtained by calculating the magnetic flux density from the volume magnetization and the magnetic field and dividing the magnetic flux density from the magnetic flux density.

(3) Residual hardness As described above, heat resistance is required for copper-based alloys for electrical and electronic parts used in lead frames. The heat resistance is evaluated by a strength that can be maintained after being held for a certain time at a certain temperature. Here, the hardness remaining rate after a heat resistance test heated at 450 ° C. for 5 minutes is evaluated as heat resistance. The hardness remaining rate is a value expressed as a percentage by dividing the Vickers hardness after the heat resistance test heated at 450 ° C. for 5 minutes by the Vickers hardness before the heat resistance test. The greater the residual hardness rate, the better the heat resistance. Therefore, the numerical limit range is 90% or more.

(4) Saturation magnetization Saturation magnetization is the magnetization when all the magnetic moments in the ferromagnetic body are aligned in the direction of the magnetic field. Here, the magnetization from 0 Oe to 55000 Oe is measured, and the volume magnetization obtained by dividing the maximum magnetization by the volume of the test piece is defined as saturation magnetization. The decrease in saturation magnetization is considered to correspond to the decrease in the volume fraction of ferromagnetic α-Fe in the Fe precipitate. The smaller the saturation magnetization, the smaller the influence on the transmission characteristics. Therefore, the numerical range is defined as described above.

  This copper-based alloy for electrical / electronic parts contains 2.1 mass% or more and 2.6 mass% or less Fe, 0.015 mass% or more and 0.15 mass% or less P, 0.05 mass% or more and 0.2 mass% or less Zn. Contained in the ingot consisting of Cu and inevitable impurities, hot rolling, first cold rolling, first heat treatment, second cold rolling, second heat treatment, third cold rolling , And a third heat treatment in sequence.

  At this time, the second heat treatment is performed by raising the temperature to a desired temperature at 1 ° C./min and lowering the temperature to the desired temperature at 1 ° C./min, and the third cold rolling has a workability of 70%. More than 80% is performed. As a result, a copper-based alloy for electric / electronic parts that satisfies the above-described characteristics can be obtained.

  As described above, according to the present invention, the relationship between the heat resistance is clarified by paying attention to the magnetism of α-Fe and evaluating the saturation magnetization of the copper-based alloy for electric / electronic parts. It is possible to provide a copper-based alloy for electric / electronic parts having a lower magnetic property and a method for producing the same while satisfying the standard characteristics of each ESH quality and maintaining heat resistance.

  Next, examples of the present invention will be described.

Example 1
First, a copper-base alloy containing 2.2 mass% Fe, 0.02 mass% P, 0.1 mass% Zn, and the balance of Cu and inevitable impurities is melted and cast in a high frequency induction heating type melting furnace. Then, a rectangular ingot having a width of 450 mm, a thickness of 200 mm, and a length of 6000 mm was produced. After this ingot was kept at a temperature of 950 ° C., hot rolling was performed until the thickness became 12 mm. The copper base alloy was cut so that the width was 20 mm, the thickness was 12 mm, and the length was 300 mm, and then the surface was ground by about 2 mm on one side. Next, first cold rolling was performed until the thickness of the copper-based alloy plate reached 2.0 mm. Thereafter, the copper-based alloy plate was immersed in a salt bath at 750 ° C. for 60 seconds, and strain relief annealing was performed as a first heat treatment. After the first heat treatment, the surface oxide film or the like was ground and the second cold rolling was performed until the thickness became 0.75 mm. Further, the copper base alloy plate subjected to the second cold rolling was wound in a coil shape, and an aging heat treatment was carried out as a second heat treatment in a batch furnace in a nitrogen atmosphere. In the second heat treatment, the temperature was raised to 450 ° C. at 1 ° C./min and held at this temperature for 15 hours. After being held, it was cooled to 100 ° C. at a cooling rate of 1 ° C./min, taken out from the batch furnace at 100 ° C., and cooled to room temperature. Thereafter, a third cold rolling was carried out at a working degree of 80% until the thickness of the cooled copper-based alloy plate became 0.15 mm. Finally, as a third heat treatment, it was immersed in a salt bath at 400 ° C. for 1 minute.

  The tensile strength, Vickers hardness, electrical conductivity, and hardness remaining rate after a heat resistance test heated at 450 ° C. for 5 minutes were evaluated. The tensile strength was evaluated based on JISZ2241: 2011 using a No. 5 test piece. The conductivity was converted from the electrical resistance as described above. At this time, the electrical resistance was measured by measuring the voltage-current characteristic (VI characteristic) using a four-terminal method with a distance between terminals of 200 mm, and using this slope as a measured value. Vickers hardness was evaluated according to JISZ2244: 2009 from a plane perpendicular to the rolling direction. At this time, the test force was 100 kgf, and the test force holding time was 10 seconds. The hardness residual rate was evaluated in the same manner as described above for the Vickers hardness of the test piece immediately immersed in a salt bath heated to 450 ° C. for 5 minutes and then immediately water-cooled. It calculated using Vickers hardness. Further, the saturation magnetization was measured by measuring the magnetization every 2000 Oe from 0 Oe to 55000 Oe using SQUID (manufactured by QUANTUM DESIGN), and the value obtained by dividing the maximum value by the volume of the test piece. The measurement temperature was 300 K, the test piece size was about 2.6 mm in diameter, and the thickness was 0.15 mm. The maximum magnetic permeability was calculated by calculating the magnetic flux density from the volume magnetization and the magnetic field, and taking the maximum value among the values obtained by dividing the magnetic field from the magnetic flux density.

This copper-based alloy strip has a tensile strength of 548 MPa, a Vickers hardness of 157 Hv, an electrical conductivity of 60% IACS, and a hardness residual rate of 94%, which satisfies the standard characteristics and heat resistance of C1940 according to ESH quality. It was. The saturation magnetization was 26.6 emu / cm ³ . This is a lower value than the conventional example described later. Furthermore, the maximum magnetic permeability was 1.046. FIG. 1 shows the result of magnetization measurement in Example 1.

(Example 2)
First, a copper-base alloy containing 2.2 mass% Fe, 0.02 mass% P, 0.1 mass% Zn, and the balance of Cu and inevitable impurities is melted and cast in a high frequency induction heating type melting furnace. Then, a rectangular ingot having a width of 450 mm, a thickness of 200 mm, and a length of 6000 mm was produced. After this ingot was kept at a temperature of 950 ° C., hot rolling was performed until the thickness became 12 mm. The copper base alloy was cut so that the width was 20 mm, the thickness was 12 mm, and the length was 300 mm, and then the surface was ground by about 2 mm on one side. Next, first cold rolling was performed until the thickness of the copper-based alloy plate reached 2.0 mm. Thereafter, the copper-based alloy plate was immersed in a salt bath at 750 ° C. for 60 seconds, and strain relief annealing was performed as a first heat treatment. After the first heat treatment, the surface oxide film or the like was ground, and the second cold rolling was performed until the thickness became 0.5 mm. Further, the copper base alloy plate subjected to the second cold rolling was wound in a coil shape, and an aging heat treatment was carried out as a second heat treatment in a batch furnace in a nitrogen atmosphere. In the second heat treatment, the temperature was raised to 450 ° C. at 1 ° C./min and held at this temperature for 15 hours. After being held, it was cooled to 100 ° C. at a cooling rate of 1 ° C./min, taken out from the batch furnace at 100 ° C., and cooled to room temperature. After that, the third cold rolling was carried out at a workability of 70% until the thickness of the cooled copper-based alloy plate became 0.15 mm. Finally, as a third heat treatment, it was immersed in a salt bath at 400 ° C. for 1 minute.

This copper-based alloy strip has a tensile strength of 546 MPa, a Vickers hardness of 161 Hv, an electrical conductivity of 62% IACS, a residual hardness of 96%, and satisfies the standard characteristics and heat resistance of C1940 according to ESH quality. It was. The saturation magnetization was 28.2 emu / cm ³ . This is a lower value than the conventional example described later. Furthermore, the maximum magnetic permeability was 1.055.

(Conventional example)
First, a copper-based alloy containing 2.2 mass% Fe, 0.03 mass% P, 0.1 mass% Zn, and the balance consisting of Cu and inevitable impurities is melted and cast in a high frequency induction heating type melting furnace. Then, a rectangular ingot having a width of 450 mm, a thickness of 200 mm, and a length of 6000 mm was produced. After this ingot was kept at a temperature of 950 ° C., hot rolling was performed until the thickness became 12 mm. And the surface and the back surface were each ground by 1 mm. Next, the first cold rolling was performed until the thickness of the copper-based alloy plate became 2.5 mm. Thereafter, in the continuous annealing furnace, the material is passed through a heating zone having an atmospheric temperature of 930 ° C. at a speed of 2.5 m / min to set the maximum temperature of the material to 925 ° C., and then passed through the cooling zone and the water-cooled pool to be rapidly cooled. A heat treatment was performed. At this time, the holding time at 900 ° C. or higher was 1 minute. After the first heat treatment, the surface oxide film or the like was ground and the second cold rolling was performed until the thickness became 0.75 mm. Further, as a second heat treatment, heating was performed at a temperature of 600 ° C. for 2 hours in an electric furnace in a nitrogen atmosphere, the temperature was lowered to 450 ° C. at a cooling rate of 5 ° C./min, and heating was performed at this temperature for 2 hours. Was lowered to room temperature at 5 ° C./min. Thereafter, the third cold rolling was carried out at a working degree of 80% until the thickness of the copper-based alloy plate taken out from the electric furnace became 0.15 mm. Finally, as a third heat treatment, a heating zone having an ambient temperature of 460 ° C. was passed at a speed of 50 m / min.

This copper-based alloy strip has a tensile strength of 546 MPa, a Vickers hardness of 166 Hv, an electrical conductivity of 62% IACS, and a hardness residual rate of 95%, satisfying the standard characteristics and heat resistance of C1940 by ESH quality. It was. However, the saturation magnetization was 31.1 emu / cm ³ and the maximum magnetic permeability was 1.061.

(Comparative Example 1)
First, a copper-based alloy containing 2.2 mass% Fe, 0.03 mass% P, 0.1 mass% Zn, and the balance consisting of Cu and inevitable impurities is melted and cast in a high frequency induction heating type melting furnace. Then, a rectangular ingot having a width of 450 mm, a thickness of 200 mm, and a length of 6000 mm was produced. After this ingot was kept at a temperature of 950 ° C., hot rolling was performed until the thickness became 12 mm. And the surface and the back surface were each ground by 1 mm. Next, the first cold rolling was performed until the thickness of the copper-based alloy plate became 2.5 mm. Thereafter, in the continuous annealing furnace, the material is passed through a heating zone having an atmospheric temperature of 930 ° C. at a speed of 2.5 m / min to set the maximum temperature of the material to 925 ° C., and then passed through the cooling zone and the water-cooled pool to be rapidly cooled. A heat treatment was performed. At this time, the holding time at 900 ° C. or higher was 1 minute. After the first heat treatment, the surface oxide film or the like was ground, and the second cold rolling was performed until the thickness became 0.5 mm. Further, as a second heat treatment, heating was performed at a temperature of 600 ° C. for 2 hours in an electric furnace in a nitrogen atmosphere, the temperature was lowered to 450 ° C. at a cooling rate of 5 ° C./min, and heating was performed at this temperature for 2 hours. Was lowered to room temperature at 5 ° C./min. Thereafter, the third cold rolling was carried out at a workability of 70% until the thickness of the copper-based alloy plate taken out from the electric furnace reached 0.15 mm. Finally, as a third heat treatment, a heating zone having an ambient temperature of 460 ° C. was passed at a speed of 50 m / min.

This copper-based alloy strip has a tensile strength of 515 MPa, a Vickers hardness of 159 Hv, an electrical conductivity of 63% IACS, and a hardness residual rate of 97%, which satisfies the standard characteristics and heat resistance of C1940 according to ESH quality. It was. However, the saturation magnetization was 31.7 emu / cm ³ and the maximum permeability was 1.062.

(Comparative Example 2)
First, a copper-based alloy containing 2.2 mass% Fe, 0.03 mass% P, 0.1 mass% Zn, and the balance consisting of Cu and inevitable impurities is melted and cast in a high frequency induction heating type melting furnace. Then, a rectangular ingot having a width of 450 mm, a thickness of 200 mm, and a length of 6000 mm was produced. After this ingot was kept at a temperature of 950 ° C., hot rolling was performed until the thickness became 12 mm. And the surface and the back surface were each ground by 1 mm. Next, the first cold rolling was performed until the thickness of the copper-based alloy plate became 2.5 mm. Thereafter, in the continuous annealing furnace, the material is passed through a heating zone having an atmospheric temperature of 930 ° C. at a speed of 2.5 m / min to set the maximum temperature of the material to 925 ° C., and then passed through the cooling zone and the water-cooled pool to be rapidly cooled. A heat treatment was performed. At this time, the holding time at 900 ° C. or higher was 1 minute. After the first heat treatment, the surface oxide film or the like was ground, and second cold rolling was performed until the thickness became 1.5 mm. Further, as a second heat treatment, heating was performed at a temperature of 600 ° C. for 2 hours in an electric furnace in a nitrogen atmosphere, the temperature was lowered to 450 ° C. at a cooling rate of 5 ° C./min, and heating was performed at this temperature for 2 hours. Was lowered to room temperature at 5 ° C./min. Thereafter, the third cold rolling was carried out at a workability of 90% until the thickness of the copper-based alloy plate taken out from the electric furnace reached 0.15 mm. Finally, as a third heat treatment, a heating zone having an ambient temperature of 460 ° C. was passed at a speed of 50 m / min.

This copper-based alloy strip has a tensile strength of 561 MPa, a Vickers hardness of 170 Hv, an electrical conductivity of 55% IACS, and a hardness residual rate of 83%, and does not satisfy the standard characteristics and heat resistance of C1940 by ESH quality. It was. The saturation magnetization was 30.2 emu / cm ³ and the maximum magnetic permeability was 1.053.

(Comparative Example 3)
First, a copper-base alloy containing 2.2 mass% Fe, 0.02 mass% P, 0.1 mass% Zn, and the balance of Cu and inevitable impurities is melted and cast in a high frequency induction heating type melting furnace. Then, a rectangular ingot having a width of 450 mm, a thickness of 200 mm, and a length of 6000 mm was produced. After this ingot was kept at a temperature of 950 ° C., hot rolling was performed until the thickness became 12 mm. The copper base alloy was cut so that the width was 20 mm, the thickness was 12 mm, and the length was 300 mm, and then the surface was ground by about 2 mm on one side. Next, first cold rolling was performed until the thickness of the copper-based alloy plate reached 2.0 mm. Thereafter, the copper-based alloy plate was immersed in a salt bath at 750 ° C. for 60 seconds, and strain relief annealing was performed as a first heat treatment. After the first heat treatment, the surface oxide film or the like was ground, and second cold rolling was performed until the thickness became 1.5 mm. Further, the copper base alloy plate subjected to the second cold rolling was wound in a coil shape, and an aging heat treatment was carried out as a second heat treatment in a batch furnace in a nitrogen atmosphere. In the second heat treatment, the temperature was raised to 450 ° C. at 1 ° C./min and held at this temperature for 15 hours. After being held, it was cooled to 100 ° C. at a cooling rate of 1 ° C./min, taken out from the batch furnace at 100 ° C., and cooled to room temperature. Thereafter, a third cold rolling was carried out at a working degree of 90% until the thickness of the cooled copper-based alloy plate became 0.15 mm. Finally, as a third heat treatment, it was immersed in a salt bath at 400 ° C. for 1 minute.

The copper-based alloy strip had a tensile strength of 565 MPa, a Vickers hardness of 168 Hv, an electrical conductivity of 50% IACS, a hardness residual ratio of 83%, and a saturation magnetization of 25.7 emu / cm ³ . Although the saturation magnetization is lower than that of the conventional example, the heat resistance is inferior. The decrease in heat resistance is due to the fact that the workability in the third cold rolling is set to 90%, which makes it impossible for the Fe precipitate to suppress the softening driving force (due to the strain accumulated in the copper-based alloy for electrical and electronic parts). This is probably because Furthermore, the maximum magnetic permeability was 1.041.

  In this example, Examples 1 and 2, the conventional example, and Comparative Examples 1 to 3 each change the degree of work in the third cold rolling. FIG. 2 shows the relationship between the hardness residual ratio and saturation magnetization as heat resistance. As can be seen from FIG. 2, the heat resistance improves as the hardness residual ratio increases, and the magnetism decreases as the saturation magnetization decreases. In both cases, the heat resistance and the saturation magnetization are reduced with the increase in the degree of work in the third cold rolling, but Examples 1 and 2 and Comparative Example 3 are the same as the conventional examples and Comparative Examples 1 and 2. It is considered that the saturation magnetization at the degree of processing is small and α-Fe is small.

  As for the transformation from γ-Fe to α-Fe, it is reported that the larger the size of the precipitate, the lower the degree of processing (for example, see Non-Patent Document 2). In Example 1 in which the saturation magnetization can be reduced, the conditions of the second heat treatment for precipitating Fe are different from those of other conventional examples, and this makes it possible to increase Fe precipitates of an appropriate size. It is considered that the transformation from γ-Fe to α-Fe was suppressed.

  In FIG. 2, in all of the conventional example, comparative examples 1 and 2, examples 1 and 2, and comparative example 3, the saturation magnetization decreases with the degree of work in the third cold rolling. This is presumably because fine precipitates are re-dissolved by processing. Therefore, the electrical conductivity actually decreases.

  As described above, according to the present invention, it has been demonstrated that a copper-based alloy for electric and electronic parts with lower magnetic properties and a method for producing the same can be provided while satisfying the standard characteristics of C1940 according to ESH quality and maintaining heat resistance. It was.

  In this example, the first heat treatment was performed by immersing in a salt bath at 750 ° C. for 60 seconds, but other methods can be used as long as the actual temperature and the time for holding the temperature are equivalent. I do not care.

Claims (5)

  Fe containing 2.1 mass% or more and 2.6 mass% or less, Fe containing 0.015 mass% or more and 0.15 mass% or less, Zn containing 0.05 mass% or more and 0.2 mass% or less, with the balance being Cu and inevitable impurities The tensile strength is 505 MPa to 590 MPa, the Vickers hardness is 145 Hv to 170 Hv, the conductivity is 60% IACS or more, and the maximum permeability is 1.045 to 1.060. Copper base alloy for electronic parts. The copper-based alloy for electrical / electronic parts according to claim 1, wherein the saturation magnetization is 26.5 emu / cm ³ or more and 30.5 emu / cm ³ or less.   The copper-based alloy for electrical / electronic parts according to claim 1 or 2, wherein the residual hardness rate after a heat resistance test heated at 450 ° C for 5 minutes is 90% or more. Fe containing 2.1 mass% or more and 2.6 mass% or less of Fe, 0.015 mass% or more and 0.15 mass% or less of P, 0.05 mass% or more and 0.2 mass% or less of Zn, and the balance from Cu and inevitable impurities Manufactured by sequentially performing hot rolling, first cold rolling, first heat treatment, second cold rolling, second heat treatment, third cold rolling, and third heat treatment on the ingot In the copper-based alloy for electrical and electronic parts,
The second heat treatment is performed by raising the temperature to a desired temperature at 1 ° C./min and lowering the temperature to a desired temperature at 1 ° C./min, and the third cold rolling has a workability of 70% or more. A copper-based alloy for electrical and electronic parts, characterized in that it is performed as 80% or less. Fe containing 2.1 mass% or more and 2.6 mass% or less of Fe, 0.015 mass% or more and 0.15 mass% or less of P, 0.05 mass% or more and 0.2 mass% or less of Zn, and the balance from Cu and inevitable impurities The ingot is sequentially subjected to hot rolling, first cold rolling, first heat treatment, second cold rolling, second heat treatment, third cold rolling, and third heat treatment. In the method for producing a copper base alloy for electronic parts,
The second heat treatment is performed by raising the temperature to a desired temperature at 1 ° C./min and lowering the temperature to a desired temperature at 1 ° C./min, and the third cold rolling has a workability of 70% to 80%. % Or less, the manufacturing method of the copper base alloy for electrical / electronic components characterized by the above-mentioned.