JP2001131657A - Copper alloy for electrical and electronic parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a copper alloy for electrical and electronic parts excellent in proof stress, electroconductivity, spring critical value, stress relaxation resistance and bending workability and moreover excellent in Sn plating properties. SOLUTION: This copper alloy for electrical and electronic parts contains, by mass, 0.5 to 2.4% Fe, 0.02 to 0.1 % Si, 0.01 to 0.2% Mg, 0.01 to 0.7% Sn and 0.01 to 0.2% Zn, and also contains <0.03% P, <=0.03% Ni and <=0.03% Mn, and the balance Cu with inevitable impurities. If required, the alloy contains 0.0005 to 0.015% Pb and/or one or two or more kinds among Be, Al, Ti, V, Cr, Co, Zr, Nb, Mo, Ag, In, Hf, Ta and B by <=1% in total.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a terminal / connector,
Copper alloys for electrical and electronic parts such as relays and busbars, especially excellent in strength (proof stress), electrical conductivity, spring limit, stress relaxation resistance, bending workability, and excellent Sn plating.
The present invention relates to copper alloys for electronic components.

[0002]

2. Description of the Related Art With the progress of electrification of automobiles, the number of poles of connectors in a wiring harness for wiring of batteries and control devices and various electric components, actuators, sensors and the like is increasing, and miniaturization thereof is required. . Further, the connector mounted near the engine unit is always under the high temperature and high vibration environment of the engine unit. Particularly, the power system (power supply) connector is heated by a large current and self-heats to a higher temperature. Therefore, such a connector (especially a female terminal) is required to have high reliability (no settling) under the above-mentioned environment.

On the other hand, as a conventional copper alloy connector material for automobiles and the like, a Cu—Fe—P alloy (CDA19400)
And Cu-Mg-P-based alloys are known. The former is an alloy in which Fe and P are co-added to precipitate an Fe-P compound to improve the strength, and an alloy in which Zn is added to improve the migration resistance (see JP-A-1-168830). ), Alloys having improved stress relaxation resistance by adding Mg (see JP-A-4-358033) are also known. In the latter, the strength and thermal creep properties are improved by co-adding Mg and P, and the tensile strength, electrical conductivity and stress relaxation resistance are improved (Japanese Patent Publication No. 1-54).
No. 420).

[0004]

In order to reduce the size of a wiring connector (especially a female terminal) of an automobile electrical component and to ensure its reliability (maintaining a contact pressure), the strength (proof strength) of the material and the spring are required. It is necessary to further improve the characteristics (spring limit value). In addition, in order to prevent sagging (reduction in fitting force over time) even when the device is kept at a high temperature for a long period of time, it is necessary to improve stress relaxation resistance. It is necessary to control. In addition, it is required to have excellent formability (particularly bending workability) for forming small connectors, and to have excellent Sn plating adhesion to reduce the contact resistance of male and female terminals and improve corrosion resistance. Can be

However, the conventional connector material Cu-F
The e-P-based copper alloy is excellent in formability, but has a problem that the spring limit value is low and the stress relaxation resistance is poor. In addition,
An alloy in which Mg is added to this system improves the spring limit value, but decreases the formability and conductivity. In addition, Cu-Mg
-P-based copper alloys are excellent in stress relaxation resistance, but have a problem that molding workability is inferior and Sn plating adhesion is inferior.
The present invention has been made in view of such problems of the prior art, and is excellent in proof stress, electrical conductivity, spring limit value, stress relaxation resistance, bending workability, and excellent in Sn plating property. The purpose is to obtain a copper alloy for electronic components.

[0006]

The copper alloy for electric / electronic parts according to the present invention has an Fe content of 0.5 to 2.4% and a Si content of 0.5%.
02-0.1%, Mg: 0.01-0.2%, Sn:
0.01 to 0.7%, Zn: 0.01 to 0.2%, P: less than 0.03%, Ni: 0.03% or less, M
n: 0.03% or less, and the balance is made up of Cu and unavoidable impurities. The copper alloy for electric / electronic parts according to the present invention may further contain Pb: 0.0005 to 0.5 if necessary.
015% or / and Be, Al, Ti, V, Cr, C
One or more of o, Zr, Nb, Mo, Ag, In, Hf, Ta, and B can be contained in a total amount of 1% or less. As inevitable impurities of the copper alloy, Bi, As, Sb and S are each individually 0.00 from the viewpoint of manufacturing.
It is desirable to limit the content of O to 3% or less and the total thereof to 0.005% or less, and further to limit the O content to 10 ppm or less and the H content to 20 ppm or less.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The component composition of the copper alloy for electric / electronic parts according to the present invention will be described below. Fe; Fe precipitates and improves the strength of the copper alloy.
However, when the content exceeds 2.4%, coarse Fe particles are crystallized or precipitated, and the bending workability is reduced.
If it is less than 1, Fe precipitation hardly occurs, strength and electrical conductivity are reduced, and recrystallized grains grow to easily generate cracks during bending. Therefore, the content of Fe is 0.5 to
2.4%. Desirably, it is 1.0 to 2.1%,
Within this range, the stress relaxation resistance and the spring limit value are further improved. More desirably, it is 1.8 to 2.0%, and within this range, the effect of suppressing the occurrence of cracks during hot rolling increases.

Si: Si deoxidizes a copper alloy in place of conventional P (Fe also contributes to deoxidation together with Si). If the P content is less than 0.03%, recrystallization by P There is an action of suppressing the inhibitory action and promoting uniform and fine recrystallization. Further, it has an effect of improving the stress relaxation resistance and the spring limit value together with Mg and Sn without significantly lowering the conductivity. These effects are not sufficiently exerted when the addition amount is less than 0.02%, while the bending workability is deteriorated when the addition amount exceeds 0.1%. Therefore, the content of Si is 0.02-0.
1%. Desirably, it is 0.03-0.07%,
Within this range, the stress relaxation resistance is further improved.

Mg: Mg has an effect of greatly improving the stress relaxation resistance and the spring limit value when co-added with solid solution Sn. However, Mg is easily oxidized, and when added in a large amount, it becomes difficult to dissolve in the air and the electrical conductivity is lowered. Therefore, in the copper alloy, a part of the action of Mg and Sn is supplemented by Si. When the addition amount of Mg in the copper alloy (Cu-Fe system) exceeds 0.2%, uniform recrystallization is hindered and bending workability deteriorates. On the other hand, when the addition amount is less than 0.01%, stress resistance is particularly high. The relaxation characteristics do not improve. Therefore, the content of Mg is set to 0.01 to 0.2%. Desirably, 0.05-0.
It is 15%, and within this range, the stress relaxation resistance and the spring limit value are further improved by co-addition with solid solution Sn. Note that Mg
When Sn and Sn are not added, no improvement in the stress relaxation resistance and the like is observed.

Sn: When Sn is added together with solid solution Mg, it has a function of greatly improving the spring limit value and stress relaxation resistance, and further improving the bending workability. However, when the added amount of Sn exceeds 0.7%, the electrical conductivity is reduced, while the amount of added Sn is less than 0.7%.
If it is less than 01%, in particular, the spring limit value and bending workability do not improve. Therefore, the content of Sn is 0.01 to 0.7%.
And Desirably, the content is 0.05 to 0.15%. In this range, the co-addition with solid solution Mg further improves the spring limit value, stress relaxation resistance and bending workability. Zn; Zn is Sn
Also, it has a great effect on preventing peeling of solder plating. However, if the content exceeds 0.2%, Zn is removed and the bending workability is deteriorated. On the other hand, if the content is less than 0.01%, Sn is removed.
Also, peeling of solder plating cannot be prevented. Therefore, Zn
Is 0.01 to 0.2%. Preferably, 0.
The effect is particularly large in this range.

P: P is mixed as an unavoidable impurity, or added as necessary for assisting deoxidation and improving the flowability of molten metal. However, when the content increases, uniform recrystallization is inhibited, so the content is less than 0.03% (including 0%).
And If the P content is 0.03% or more, even if Si is added at 0.02% or more, a uniform and fine recrystallized structure cannot be obtained by intermediate annealing. In this case, even if the temperature of the intermediate annealing is increased, a non-recrystallized portion remains, and the copper alloy sheet has a variation in hardness, thereby deteriorating the bending workability. In addition, this unrecrystallized portion is within the range of annealing conditions usually performed in a mass production process.
It cannot be eliminated simply by increasing the number of times of annealing to two or more. The P content is desirably 0.005% or less. This is because, in a copper alloy containing Fe, Si, Mg, and Sn in the above range, by limiting P to this range, the peak of the improvement in conductivity due to the precipitation of Fe during the intermediate annealing and the completion of recrystallization. (The recrystallization is almost completed when the conductivity reaches a peak). Thereby, both high conductivity and excellent bending workability can be achieved.

Ni; Ni is mixed as an unavoidable impurity,
Alternatively, since the copper alloy has an effect of strengthening grain boundaries and preventing cracking during hot rolling, it is added as necessary. However, if it exceeds 0.03%, a Ni—Si intermetallic compound is formed, and the stress relaxation resistance is reduced. Therefore,
The content is 0.03% or less (including 0%). Mn: Mn is mixed in as an unavoidable impurity, or is added as necessary because it has an effect of strengthening grain boundaries in the copper alloy and preventing cracking during hot rolling. But,
If it exceeds 0.03%, a Mn-Si intermetallic compound is formed, and the stress relaxation resistance is reduced. Therefore, the content is set to 0.03% or less (including 0%). Preferably, 0.
01% or less. Pb; Pb is mixed as an unavoidable impurity, or added as necessary to improve the cutting property and the press punching property. Pb does not affect the properties of the final product sheet, but if it exceeds 0.015%, it segregates at the grain boundaries and cracks during hot rolling, while 0.0005%
If less than the above, the above effect cannot be obtained. Therefore, the content of Pb is set to 0.015% or less (including 0%), and when the above action is required, the content of Pb is set to 0.0005% or more.

Be-B: These elements are added as necessary because they are mixed as unavoidable impurities or have the effect of increasing the recrystallization temperature and improving the stress relaxation resistance. However, the precipitation or crystallization of these elements lowers the electrical conductivity, so that the total amount is restricted to 1% or less.
Desirably, it is 0.5% or less. Bi to H; these elements are mixed as unavoidable impurities. Bi, As, Sb and S segregate at the grain boundaries and generate cracks during hot rolling, so that each is individually 0.003%.
Hereinafter, it is desirable to limit the total to 0.005% or less. If the amount of O and H is large, blowholes are generated in the ingot, and if the amount of O is large, a large amount of oxides are generated in the molten metal and hinders the flow of the molten metal, so that the O content is 10 ppm or less and the H content is 2 ppm.
It is desirable to limit it to 0 ppm or less.

The copper alloy for electric / electronic parts is subjected to a homogenization treatment after casting, followed by hot rolling, followed by cold rolling and intermediate annealing as shown in the following Examples, It can be manufactured by a general manufacturing method of performing finish annealing after cold rolling. Cold rolling and intermediate annealing can be repeated twice or more as necessary. Further, when annealing is performed for a short time at 650 ° C. to 750 ° C. for 5 to 20 seconds between cold rolling and intermediate annealing, recrystallization occurs earlier during this annealing treatment, and Fe particles that inhibit recrystallization are formed. Does not precipitate. When the sheet material in this recrystallized state is annealed by the subsequent intermediate annealing, precipitation of Fe occurs, conductivity and strength can be improved, and a recrystallized structure in which an unrecrystallized portion does not remain can be obtained.
Bending workability can be further improved.

[0015]

Next, examples of the copper alloy for electric / electronic parts according to the present invention will be described in comparison with comparative examples. Tables 1 and 2
Copper alloys having the compositions shown in (Examples of the present invention) and Tables 3 and 4 (Comparative Examples) were melted and cast under a charcoal coating in the air in a crypt furnace. Here, the castability was determined. Then, after holding the ingot at 800 ° C. to 1000 ° C. for 30 minutes, the working ratio was 50%.
% To 80% hot rolling was performed to produce a plate material having a thickness of 18 mm. Here, whether or not cracks occurred during hot rolling was determined visually and by fluorescent flaw detection. In addition, the fluorescent flaw detection method, apply the fluorescent dye Super Glow DN-2800II for penetrant flaw detection made by Mark Tech Co., Ltd. on the entire surface of these test materials, wash and dry,
Similarly, after developing by spraying Super Glow DN-600S as a developer, the test material was irradiated with ultraviolet light.

[0016]

[Table 1]

[0017]

[Table 2]

[0018]

[Table 3]

[0019]

[Table 4]

Next, this hot-rolled material was introduced into a facing machine in the next step, and it was determined whether or not the milling blade of the facing machine had seizure. The milling blade at this time uses chromoly-based steel as the base metal,
The milling blade part is a tungsten carbide carbide tip brazed to a base metal with silver brazing, and the peripheral speed of the blade is 6
m / sec, and the cutting amount is 1.5 mm / 1 surface. No cutting oil is used. 200mm width x 18mm thickness x 1 length
Twenty hot-rolled materials having a size of 80 mm were prepared for each alloy, and the entire surface of both surfaces was ground until all of them became a thickness of 15 mm. Then, the surface of the milling blade was observed by SEM to investigate the state of seizure on the surface. If there was any trace of chip welding on the blade surface, it was determined that there was seizure.

Based on the above criteria, it was first confirmed whether or not the alloy sheet according to the present invention could be prepared. Table 5 shows the results.
As shown in Table 5, no. 44 was castable,
The amount of added Pb was excessive, and cracks occurred during hot rolling. N
o. 50 has a large amount of H and O because the seal for shielding the molten metal from the atmosphere is not sufficient.
Casting was abandoned because oxides of i, Mg, and Sn were generated in the molten metal and the flowability of the molten metal was extremely deteriorated. No. No. 43 could be cast and hot rolled, but the amount of Pb added was small and seizure of the milling blade occurred.

No. 45-49 could be cast,
No. In Nos. 45 to 48, Bi, As, Pb, and S were individually excessive. In No. 49, the total amount of Bi, As, Pb, and S was excessive, and all of them generated cracks during hot rolling. N
o. 42 was castable, but the deoxidizing agent Si was small,
In addition, since there was no addition of P, the ingot casting surface became rough, that is, brittle porous due to insufficient deoxidation. Therefore, the subsequent steps were abandoned. On the other hand, No. 1 having a composition within the specified range of the present invention. In the case of Nos. 1 to 23 (and Nos. 24 to 41 and 51 in which the content of some elements is out of the specified range), the ingot quality and hot ductility are good, and a hot-rolled material can be easily obtained. Does not occur, and the life can be extended.

[0023]

[Table 5]

Subsequently, No. Hot-rolled sheets of copper alloys of Nos. 1-41 and 51 are cold-rolled to a thickness of 2.5 to 0.50 mm, and intermediate annealing is performed in an electric furnace at a temperature of 370 to 600 ° C. for 1 to 20 minutes.
Conducted for hours. Next, after removing the oxide scale of the plate, the recrystallization ratio and the hardness distribution of the plate were measured (details will be described later). Further, this annealed material is cold-rolled to a thickness of 0.25 mm, and finish annealing is performed within a range of 250 ° C to 490 ° C.
Seconds to 2 hours. Table 6 shows the manufacturing conditions of each copper alloy.
Finally, the plate was pickled to remove oxidized scale, thereby obtaining a plate of a final product. In addition, all alloys could be easily manufactured to the shape and thickness of the final product.

[0025]

[Table 6]

The following properties (1) to (4) were measured for the in-process material after the intermediate annealing and the final product obtained in the above-described manufacturing process in the following manner. The results are shown in Tables 7 and 8. Recrystallization rate after intermediate annealing Embedding in a polishing resin so that the cross section of the sheet material can be observed, mirror-polished, and then observed with an optical microscope with a magnification of 200 or more.
The percentage of the area where recrystallization was completed was evaluated. When the recrystallization ratio is 90% or more, the mechanical properties of the final product such as bending workability are not affected.

Standard deviation of measured hardness of sheet material after intermediate annealing After buffing the surface of the sheet material, use a micro Vickers hardness tester with a load of 10 to 100 g, and use 30 points of hardness between 50 μm in a direction perpendicular to rolling. It was evaluated by calculating the standard deviation of the distribution of the 30 measured values.
If the standard deviation is less than 5, recrystallization is completed uniformly and does not affect the mechanical properties of the final product such as bending workability. Strength of final product Strength, which is a mechanical property that is particularly important as a terminal material for automobiles, is measured by preparing a JIS No. 5 tensile test piece by machining and performing a tensile test with a universal testing machine UH-10B manufactured by Shimadzu Corporation. Measured. Here, the proof stress is a tensile strength corresponding to a permanent elongation of 0.2% specified in JISZ2241. When the proof strength is 450 N / mm ² or more, the contact fitting force required for a small power supply connector for an automobile is maintained, and the connector can withstand squeezing when a male terminal is inserted.

The conductivity of the final product was measured by a four-terminal method using a double bridge 5752 manufactured by Yokogawa Electric Corporation in accordance with the conductivity measurement method for non-ferrous metal materials specified in JIS H505. Conductivity 50%
If it is IACS or more, self-heating can be suppressed by a small power supply connector for an automobile. Spring Limit Value of Final Product The spring limit measurement value was measured in accordance with the spring limit value moment test specified in JIS H3130. If the spring limit is 300 N / mm ² or more, the contact fitting force required for a small power supply connector for an automobile can be maintained.

The upper limit temperature of the stress relaxation property of the final product The stress relaxation property was measured by using a cantilever method. Specifically, a width of 10 mm from a direction perpendicular to the rolling direction of the material.
The test piece was cut out at a distance of 10 mm at the start of the test so that a surface stress equivalent to 80% of the material strength was applied to the material. Each material was held for 1000 hours in each oven set to 120 to 160 ° C. in increments of 5 ° C., and how close the sled L after unloading was to the 10 mm sled within the initial elasticity range. It was evaluated by measuring the ratio R. That is, R = (10−L) / 1
0x100 (%) was calculated and compared. In this evaluation R:
When the maximum temperature at which 70% or more can be maintained is 150 ° C. or higher, the contact fitting force required for a small power supply connector for an automobile can be maintained.

The critical bending radius of 180 ° bending in the longitudinal direction of rolling of the final product The bending workability of the 180 ° bending test is a V-block bending jig having each bending radius in a V-block method bending test specified in JISZ2248. Pre-bending with a load of 1 ton using Shimadzu Universal Testing Machine RH-30, sandwiching the test material processed to a width of 10 mm and a length of 35 mm, and further pre-bending on a flat metal table The pieces were placed and adhered with a load of 1 ton using a universal testing machine RH-30 manufactured by Shimadzu Corporation. The bending workability is determined for each bending radius of the bending jig.
A microscope was used to determine whether or not the bent portion of the test material exhibited cracks or the like. In this evaluation, if the minimum bending radius is 0 mm with respect to the material plate thickness of 0.25 mm, a small power supply connector for an automobile can be formed.

The critical bending radius of W bending in the direction perpendicular to the rolling direction of the final product The bending workability of the W-shape is specified in the CESM0002 metal material W bending test method, and is 10 mm in width using a B-type bending jig having each bending radius. A test material processed to a length of 35 mm was sandwiched and subjected to bending with a load of 1 ton using a universal testing machine RH-30 manufactured by Shimadzu Corporation. The bending workability was determined by examining the bending radius of the bending jig with a magnifying glass to determine whether or not the bent portion of the test material exhibited cracks or the like. In this evaluation, the minimum bending radius is 0.125 m for a material thickness of 0.25 mm.
m or less, a compact power supply connector for an automobile can be formed.

Presence / absence of Sn plating peeling of the final product Sn plating adhesion was as follows: stannous sulfate 40 g / lit, sulfuric acid 100 g / lit, cresolsulfonic acid 30 g / l.
it, formalin 5 mlit / lit, dispersant 20 g /
lit, a Sn plating bath having a plating thickness of 1.5 μm at a current density of 2.5 A / dm ^{2 in a} Sn plating bath (20 ° C.) composed of 10 mlit / lit and then heated in an oven at 105 ° C. for 500 hours And then 2mmR 180
After bending at ℃, the plate was bent back and the presence or absence of peeling of Sn plating from the material at that time was visually evaluated. If the Sn plating does not peel off in this evaluation, it can be used for a small power supply connector for an automobile.

The final product sheet was examined by cross-sectional observation to determine the presence or absence of foreign matter that would cause deterioration of the sheet material, such as oxides, coarse precipitates, coarse crystallization, and grain boundary reaction type precipitation. Specifically, after embedding in a polishing resin so as to allow the cross section of the product plate material to be observed and mirror-finished, the product was observed with an optical microscope having a magnification of 200 or more to confirm the presence or absence of the foreign matter. Further, in addition to the observation with an optical microscope, the cross section of the product plate material may be represented as a representative portion by 1 mm from the center and both ends.
A plate material of 0 mm x 10 mm x 0.25 mm was cut out, embedded in a polishing resin so that the cross section could be observed, and after mirror polishing, the cross section was observed with EDX-SEM to detect foreign substances, measure dimensions, and identify the composition. . When there is one or more oxides or crystallized substances having a diameter of 1 μm or more in a range of 30 μm × 50 μm, it is determined that there is an oxide or crystallized substances.

[0034]

[Table 7]

[0035]

[Table 8]

As shown in Table 7, No. 1 having a composition within the specified range of the present invention. 1 to 23 all have good properties,
It is a copper alloy for electric / electronic parts suitable for connector materials for automobiles and the like. On the other hand, as shown in Table 8, 24 (CD
A19400) has a high yield strength and a high electrical conductivity, but can obtain only a low spring limit value of 231 N / mm ² which is insufficient for an application requiring a high spring limit value such as a connector or a relay. Also, the stress relaxation resistance upper limit temperature is only 120 ° C., which is comparable to that of phosphor bronze. No. 25 (Tokuhei 1
-Cu-Mg-P alloy disclosed in -54420)
Has both high yield strength, high electrical conductivity, high spring limit value, and high stress relaxation property, but is inferior in bending workability and Sn plating property.

No. 26, 27 (an alloy obtained by adding Mg, Sn, and Zn to a P-deoxidized Cu-Fe alloy similar to the CDA19400 alloy) have high yield strength, high electrical conductivity, high spring limit value,
Although it has high stress relaxation resistance, recrystallization is not easy by intermediate annealing within a practical range because Si is not added. Therefore, the hardness after intermediate annealing is not uniform, and bending is performed. The property is deteriorated. No. No. 28 has an excessively small amount of Fe and can secure a conductivity of 60% IACS or more.
Poor mechanical properties such as spring limit value, stress relaxation resistance and bending workability. No. No. 29 has an excessive amount of added Si, high yield strength,
Although a high spring limit value and high stress relaxation resistance can be obtained, the conductivity is lower than 50% IACS, and the bending workability is also poor. No.
30 shows that the amount of added Si is appropriate but the amount of added P is excessive,
Recrystallization is not easy by the intermediate annealing within the practical range, and the product quality is not uniform. Therefore, the hardness after the intermediate annealing is not uniform, and the bending workability is deteriorated.

No. No. 31 has an excessive amount of added Mg, the rolled structure introduced in the cold rolling step after hot rolling does not disappear by the intermediate annealing, a uniform fine recrystallized structure cannot be obtained, and bending workability is poor. No. Nos. 32, 33, and 35 do not contain both Mg and Sn in appropriate amounts, and have spring limit values (No. 32, 33,
35), bending workability (No. 32, 33, 35) and stress relaxation resistance (No. 35) are inferior. No. 34 is Sn
, But Mg is not added, and the stress relaxation resistance is poor. No. No. 36 contains an appropriate amount of Mg, but Sn
Is not added, and the stress relaxation resistance and bending workability are poor. No. No. 37 has too little Zn addition and is inferior in Sn plating property. No. No. 38 has an excessive addition amount of Zn, so that one element having a solid solution strengthening action is added in addition to Sn and Mg, so that bending workability is deteriorated. No. Reference numeral 39 denotes Si which has an excessive amount of added Ni and improves stress relaxation resistance.
Is deprived of the formation of the Ni-Si intermetallic compound, thereby deteriorating the stress relaxation resistance, and further deteriorating the bending workability due to the generation of the intermetallic compound. No. In No. 40, an excessive amount of Mn is added, and Si for improving the stress relaxation resistance is deprived of the formation of the Mn-Si intermetallic compound, thereby deteriorating the stress relaxation resistance and further deteriorating the bending workability due to the generation of the intermetallic compound. I do.

No. 41 is excessive in the amount of Fe added, and coarse Fe was observed in the cross-sectional structure observation by the optical microscope and EDX-SEM.
Generation of particles was confirmed. Therefore, bending workability was extremely deteriorated. No. 51 has an excess of elements such as Ti,
Observation of the cross-sectional structure by the optical microscope and EDX-SEM
Generation of coarse particles of i, Cr, and Zr was confirmed. Therefore, bending workability was extremely deteriorated.

Next, in order to confirm that Pb does not affect each property of the final product sheet, the Pb content was set to 0.000.
A final product plate was produced from a copper alloy having the composition shown in Tables 9 (a) and 9 (b) suppressed to 1%. In this case, when removing the oxide scale generated by hot rolling, welding and seizure occur on the milling blade, so a hot rolling step was applied to avoid this. Specifically, the ingot is cast in a mold assembled so that the thickness of the ingot becomes 36 mm, and is maintained at a heating temperature of 800 ° C. where almost no oxide scale is generated, for 30 minutes, and a processing rate of 50% is added by only one pass. A hot-rolled sheet having a thickness of 18 mm was subjected to face milling using a milling blade in the same manner as in the previous example. At this time, the slightly generated primary scale is completely crushed,
In addition, since no intrusion of the oxide scale occurs, welding and seizure do not occur on the milling blade even if Pb is not particularly contained at 0.0005% or more. In the actual operation where importance is placed on efficiency, since a large ingot is used, it is inevitable that the number of hot rolling passes is increased and the secondary scale is generated and pushed. These oxide scales serve as adhesion nuclei for the milling blade, which may cause welding and seizure on the milling blade. The previous No. In Nos. 1 to 51, in order to reproduce this situation, hot rolling was performed in 5 to 8 passes.

[0041]

[Table 9]

Thereafter, cold rolling, intermediate annealing and finish annealing were performed under the conditions shown in Table 9 (c) to obtain a sheet material of a final product. The properties of the in-process material and the final product after the intermediate annealing obtained in this manufacturing process were measured in the same manner as in the previous examples. As shown in Tables 9 (d) and (e), Pb
No. which was suppressed to 0.0001%. 52 also gives a finished product plate with excellent properties.

[0043]

The copper alloy for electric / electronic parts according to the present invention has strength (proof strength), electrical conductivity, spring limit value, stress relaxation resistance, bending workability, Sn plating property, etc.
It has all of the characteristics required for materials for electric and electronic parts such as relays and bus bars, and is particularly suitable as a wiring material for automobiles, especially a material for small connectors for power supply. In addition, the copper alloy for electric / electronic parts according to the present invention can be manufactured at low cost and with high productivity by adding Si having a deoxidizing action to minimize the amount of P that inhibits uniform recrystallization. There are advantages.

Claims (4)

[Claims] 1. Fe: 0.5 to 2.4% (mass%, the same applies hereinafter), Si: 0.02 to 0.1%, Mg: 0.01 to
0.2%, Sn: 0.01 to 0.7%, Zn: 0.01
~ 0.2%, P: less than 0.03%, Ni: 0.
A copper alloy for electric / electronic parts comprising not more than 03% and not more than 0.03% of Mn, and the balance being Cu and unavoidable impurities. 2. Pb: 0.0005 to 0.01
The copper alloy for electric / electronic parts according to claim 1, which contains 5%. 3. Be, Al, Ti, V, Cr, Co, Z
The copper for electric / electronic parts according to claim 1 or 2, wherein one or more of r, Nb, Mo, Ag, In, Hf, Ta, and B are contained in a total amount of 1% or less. alloy. 4. Bi, As, Sb and S are each individually 0.003% or less, and the total thereof is 0.005%.
And the O content is 10 ppm or less, and H
The copper alloy for electric / electronic parts according to any one of claims 1 to 3, wherein the content is 20 ppm or less.