JP2000328158A - Copper alloy sheet excellent in press punchability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an alloy sheet maintaining the excellent strength and electri cal conductivity of a Cu-Fe-P alloy and excellent in press punchability by allowing it to have a specified compsn. and allowing the respective X-ray diffrac tion intensity from the 200} plane, 311} plane and 220} plane in the sheet surface, i.e., I 200}, I 311} and I 220} to satisfy specified relation. SOLUTION: This alloy sheet contains, by weight, 0.005 to 0.5% Fe and 0.005 to 0.2% P, and the balance Cu with inevitable impurities. Among the X-ray diffraction intensity, the inequality of [I 200} +I 311}]/I 220}<0.4 is satisfied. Preferably, either or both of 0.01 to 10% Zn and 0.01 to 55% Sn may be incorporated therein. This alloy sheet moreover contains one or >= two kinds of elements selected from each element of B, C, S, Ca or, the like, respectively of 0.0001 to 0.1% (by <=0.1% in total in the case >= two kinds are added) and each element of Be, Mg, Al, or the like, respectively of 0.001 to 1% by <=1% in total.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper alloy plate, and more particularly to a copper alloy plate having excellent press punching properties suitable for use in electronic components such as lead frames, terminals, connectors, switches, relays and the like.

[0002]

2. Description of the Related Art Various copper and copper alloys are used for various electronic components. 2. Description of the Related Art In recent years, the trend toward lighter, smaller, and smaller electronic components has been rapidly advancing. Along with this, copper alloy plates used for lead frames, terminals, connectors, switches, relays, etc. are required not only to have high strength and high electrical conductivity, but also to be stamped into a fine shape and to have excellent press punching properties. Is increasing. Above all, Cu
-Fe-P alloys are widely used in these applications as alloys having both high strength, high heat resistance and high electrical conductivity. However, at the present time, it is difficult to achieve both these characteristics and press punching properties.

[0003]

Conventionally, as a method for improving the press punching property, it is customary to pay attention to chemical components such as adding a minor component such as Pb or Ca, or dispersing a compound which is a starting point of fracture. there were. However, such a method has problems that it is difficult to control a trace component, deteriorate other characteristics, and increase the cost. The present invention has been made in view of the above problems of the prior art, excellent strength of Cu-Fe-P based alloy,
An object of the present invention is to obtain a copper alloy sheet having excellent press punching properties while maintaining conductivity and the like.

[0004]

Means for Solving the Problems The inventor of the present invention has made intensive studies on Cu-Fe-P alloy sheets to solve the above-mentioned problems, and as a result, has improved press punching properties by controlling the degree of integration of crystal orientations. They have found what they can do and accomplished the present invention. That is, the copper alloy sheet according to the present invention has F
e: 0.005 to 0.5 wt%, P: 0.005 to 0.
2 wt%, the balance being Cu and unavoidable impurities. Further, the X-ray diffraction intensity from the {200} plane on the plate surface is I {200}, and the X-ray diffraction intensity from the {311} plane is I {311}.
When the X-ray diffraction intensity from the {220} plane is I {220}, the following formula is satisfied. [I {200} + I {311}] / I {220} <0.4

[0005] The above copper alloy plate is made of Zn: 0.01.
-10 wt%, Sn: 0.01-5 wt%, or both. Further, the above-mentioned copper alloy plate is made of B, C, S, Ca, V, Ga, Ge, Nb,
Mo, Hf, Ta, Bi, and Pb elements 0.0001 to
0.1wt% (When adding two or more, 0.1w% in total
t% or less), Be, Mg, Al, Si, Ti, Cr, M
n, Ni, Co, Zr, Ag, Cd, In, Sb, T
One or more elements selected from 0.001 to 1 wt% of each element of e and Au can be contained in a total of 1 wt% or less.

[0006]

Next, the reasons for limiting the components and crystal orientation of the copper alloy according to the present invention will be described. (Fe and P) These components form an intermetallic compound of Fe and P in a coexisting state, and thus have the effect of improving the strength without significantly lowering the conductivity. F
e is less than 0.005 wt% or / and P is 0.005 w
If the content is less than t%, the effect is not obtained. If the content of Fe exceeds 0.5% by weight and / or the content of P exceeds 0.2% by weight, the hot workability is significantly reduced. Therefore, both components are Fe: 0.005 to
0.5 wt%, P: 0.005 to 0.2 wt%.
Note that Fe and P are crystal orientation indices ([I {200} + I {311}]).
/ I {220}) to improve press punchability.

(Zn) Zn has an effect of improving the heat-resistant peeling resistance and the migration resistance.
If it is less than 1 wt%, the effect is not sufficient. 10wt%
If it exceeds, not only the conductivity will decrease but also the solderability will decrease and the sensitivity to stress corrosion cracking will increase, which is not preferred. Therefore, Zn is set to 0.01 to 10% by weight. Note that Zn has a function of lowering the crystal orientation index and improving the press punching property. (Sn) Sn is a component that improves strength by solid solution strengthening. If the content is less than 0.01 wt%, the effect is not sufficient, and if it exceeds 5 wt%, the effect is saturated, and
Hot and cold workability deteriorates. Therefore, Sn is 0.0
1 to 5 wt%. Note that Sn has a function of lowering the crystal orientation index and improving the press punching property.

(Subcomponents) B, C, S, Ca, V, Ga,
Each element of Ge, Nb, Mo, Hf, Ta, Bi, and Pb has a role of further improving the press punching property. If these elements are less than 0.0001% by weight, they have no effect, and if they exceed 0.1% by weight, the hot workability deteriorates. Also, Be, Mg, Al, Si, Ti, Cr, Mn, N
i, Co, Zr, Ag, Cd, In, Sb, Te, Au
Each element has a role of improving the press punching property, and further improves the strength by coexistence with the Fe-P compound. If these elements are less than 0.001 wt%, their effects are not obtained, and if they exceed 1 wt%, the hot and cold workability is deteriorated and the electric conductivity is also lowered. Therefore, the above B to P
For b, each element is 0.0001 to 0.1 wt% (when two or more kinds are added, the total is 0.1 wt% or less).
For e to Au, each element is 0.001 to 1 wt%,
The total of both is set to 1% by weight or less.

(Crystal orientation) A copper alloy sheet containing Fe and P is recrystallized, and as the grain size increases, the accumulation ratio of {200} and {311} planes on the sheet surface increases.集 積 The accumulation ratio of the surface will increase. The copper alloy sheet according to the present invention is manufactured by, for example, hot rolling, cold rolling, precipitation annealing, finish cold rolling, and strain relief annealing. In this manufacturing process, for example, precipitation annealing (annealing temperature, time ) And the subsequent cold rolling step (working rate), the accumulation ratio can be controlled. Specifically, the annealing temperature is preferably 475 ° C. or less, and the cumulative working ratio after the precipitation annealing is preferably 55% or more. It should be noted that this accumulation ratio does not change significantly by subsequent strain relief annealing without recrystallization. Further, the contents of Fe and P, and the contents of other elements also affect the accumulation ratio. In the present invention, based on the knowledge that these accumulation ratios have a strong correlation with the press punching property and that the press punching property can be improved by controlling these accumulation rates on the sheet surface, as shown in the above formula, And an appropriate range of the crystal orientation index. The value of the crystal orientation index is also related to the bending workability of the sheet. If the value is too small, the bending workability of the sheet deteriorates. Therefore, this value is preferably 0.1 or more.

[0010]

Next, examples of the present invention will be described below together with comparative examples. A copper alloy having the chemical composition shown in Table 1 was
The mixture was melted in the air under a charcoal coating in a crypt furnace and cast into a book mold to produce an ingot of 50 × 80 × 200 mm. This ingot was heated to 930 ° C., hot-rolled, and immediately quenched in water to obtain a hot-rolled material having a thickness of 15 mm. The surface was cut with a grinder to remove oxide scale on the surface of the hot rolled material. After cold rolling, this was subjected to precipitation annealing at 425 ° C. for 2 hours, and further adjusted to a sheet thickness of 0.25 mm by finish cold rolling at a cold working rate of 60%. This material was subjected to a strain relief annealing at 350 ° C. for 20 seconds and then subjected to a test.

[0011]

[Table 1]

In addition to the above steps, in order to obtain copper alloy plates having various crystal orientation accumulation ratios, For the alloy having the composition No. 3, the precipitation annealing temperature was set to 450 ° C. (N
o. 3-2), manufactured under the conditions of 500 ° C (No. 3-5). The cold working rate after precipitation annealing is 30% in addition to 60%.
(No. 3-6), 40% (No. 3-7), 50% (No.
3-3) and 70% (No. 3-4). Under any conditions, the final thickness was adjusted to 0.25 mm.

With respect to these test materials, tensile strength, proof stress, electrical conductivity, flash height, and crystal orientation were examined in the following manner. The results are shown in Tables 2 and 3. The stress corrosion cracking resistance was also evaluated in the following manner. <Tensile strength, yield strength> The method described in JIS Z 2241 was used. The proof stress was set by a permanent elongation of 0.2 by the offset method.
%It was adopted. As the test piece, a No. 5 test piece of JIS Z 2201 was used. <Electric conductivity> The method described in JIS H 0505 was used. The electric resistance was measured using a double bridge. <Burr height> 250s with mold clearance of 10%
A lead having a length of 30 mm and a width of 0.5 mm was punched at a punching speed of pm, and the burrs were measured by SEM observation. <Crystal Orientation> X-rays were incident on the surface of the copper alloy plate in the final product state (0.25 mm thickness), and the intensity from each diffraction surface was measured. Although the measurement depth from the surface changes depending on the incident angle, crystal orientation data up to a depth of about 20 to 30 μm can be obtained. Among them, there is strong correlation with bending workability.
The crystal orientation index was determined by comparing the diffraction intensity ratios of the 00, {311} and {220} planes. The X-ray irradiation conditions were as follows: X-ray type: CuK-α1, tube voltage: 40 kV,
Tube current: 200 mA, measured while rotating the sample in a plane. <Stress corrosion cracking resistance>Thompson's method (DHThomps
on: The test was performed according to Materials Research & Standards 1 (1961), 108). 0.25mmt × 1
As shown in FIG. 1 (a), the size was set to 2.7 mmw × 150 mm, and after being tied in a loop shape, it was exposed to 14 wt% aqueous ammonia saturated steam. The distance between both ends of the test piece when the knot was released was measured, and the stress relaxation rate was measured by the following equation. 20
Those having a stress relaxation rate of 50% or more within the time were evaluated as having poor stress corrosion cracking resistance. Stress relaxation rate (%) = [(l ₁ −l ₂ ) / l ₁ × 100 l ₁ : distance between both ends of test specimen before exposure to ammonia l ₂ : distance between both ends of test specimen after exposure to ammonia

[0014]

[Table 2]

[0015]

[Table 3]

[0016] In Table 2, No. Each of Nos. 1 to 18 has good characteristics. Among them, No. 1 and No.
In No. 2, Fe and P are relatively low, the strength is slightly low, the crystal orientation index is high, and the burrs are slightly large. Conversely, no. 4 and 5
Since Fe and P are high, the strength is slightly high, the crystal orientation index is low, and the burrs are small. No. 3-2 and 3-3 have higher crystal orientation indices, and the burrs are slightly larger. On the other hand, in Comparative Example No. 3 shown in Table 3, No. 19 has low strength because Fe and P are low, and has large burrs because the crystal orientation index is high. Comparative Example No. In No. 20, since Fe and P were high, cracks occurred during hot rolling. Comparative Example No. Since No. 21 has a large amount of Zn, it has low stress corrosion cracking resistance and low electric conductivity. Comparative Example No. 22, no. No. 23 had a high Sn or Pb content, and cracks occurred during hot rolling. No. No. 24 has a high Fe content, causes microcracks during hot rolling, and has a low conductivity. No. 3-5, 3-6, 3-7
Has a high crystal orientation index and large burrs.

[0017]

According to the present invention, a copper alloy plate for an electronic component such as a lead frame, a terminal, a connector, a switch, and a relay having excellent press punching property while maintaining excellent strength and conductivity is provided. Obtainable.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method of a stress corrosion cracking resistance test.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C22C 9/06 C22C 9/06 9/10 9/10

Claims (5)

[Claims] 1. Fe: 0.005 to 0.5 wt%, P:
Containing 0.005 to 0.2 wt%, the balance being Cu and unavoidable impurities. Further, the X-ray diffraction intensity from the {200} plane on the plate surface is I {200}, and the X-ray diffraction intensity from the {311} plane is I {311}, a copper alloy sheet having excellent press punching properties, characterized by satisfying the following equation, where X-ray diffraction intensity from the {220} plane is I {220}. [I {200} + I {311}] / I {220} <0.4 2. Fe: 0.005 to 0.5 wt%, P:
0.005 to 0.2 wt%, Zn: 0.01 to 10 wt
%, The balance consisting of Cu and unavoidable impurities, and the X-ray diffraction intensity from the {200} plane
0}, the X-ray diffraction intensity from the {311} plane is expressed as I {311}, {2
A copper alloy sheet having excellent press punching properties, characterized by satisfying the following formula, where the X-ray diffraction intensity from a 20 ° plane is I {220}. [I {200} + I {311}] / I {220} <0.4 3. Fe: 0.005 to 0.5 wt%, P:
0.005 to 0.2 wt%, Sn: 0.01 to 5 wt%
And the balance consisting of Cu and unavoidable impurities. Further, the X-ray diffraction intensity from the {200} plane on the plate surface is I {20
0}, the X-ray diffraction intensity from the {311} plane is expressed as I {311}, {2
A copper alloy sheet having excellent press punching properties, characterized by satisfying the following formula, where the X-ray diffraction intensity from a 20 ° plane is I {220}. [I {200} + I {311}] / I {220} <0.4 4. Fe: 0.005 to 0.5 wt%, P:
0.005 to 0.2 wt%, Zn: 0.01 to 10 wt
%, Sn: 0.01 to 5 wt%, the balance consisting of Cu and unavoidable impurities, and further, the X-ray diffraction intensity from the {200} plane on the plate surface is expressed by I {200} and X from the {311} plane.
A copper alloy sheet having excellent press punching properties, wherein the following formula is satisfied, where X-ray diffraction intensity is I {311} and X-ray diffraction intensity from the {220} plane is I {220}. [I {200} + I {311}] / I {220} <0.4 5. B, C, S, Ca, V, Ga, Ge, N
each element of b, Mo, Hf, Ta, Bi, Pb 0.000
1-0.1 wt%, Be, Mg, Al, Si, Ti, C
r, Mn, Ni, Co, Zr, Ag, Cd, In, S
One, two or more elements selected from 0.001 to 1 wt% of each element of b, Te and Au are 1 wt% in total.
The copper alloy sheet having excellent press punching properties according to any one of claims 1 to 4, wherein the copper alloy sheet contains: