JPS62120451A - Copper alloy for press fit pin - Google Patents

Abstract

PURPOSE:To improve strength, spring characteristic, and workability by incorporating specific amounts of Ni and Si to a copper alloy. CONSTITUTION:An alloy has a composition containing, by weight, 0.4-4.0% Ni, 0.1-1.0% Si, and, as auxiliaries, 0.001-2.0%, in total, of one or more kinds among 0.001-1.0% each of P, Sn, As, Cr, Mg, Mn, Sb, Fe, Co, Al, Ti, Zr, Be, Zn, B, and each element of lanthanides and having the balance Cu with inevitable impurities. This alloy is aged so that Hv160-200 hardness is obtained. A copper alloy for press fit pin having the above composition is free from cracking and die wear in press working and simultaneously it has superior strength and spring characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION (Objects of the Invention) The present invention relates to a copper alloy for a press-fit pin that is held in contact with a metal hole of a printed circuit board or the like by the spring properties of the joint portion of the pin without using solder.

(Prior art) Conventionally, press-fit pins are used to contact and hold metal holes in printed circuit boards, etc., using the spring properties of the bottle without using solder. shapes are proposed. Since these joints are minute and complex, and are formed through heavy working, the hardness of the joints is extremely high, and cracks can occur if the shape or material of the joint is incorrect.

Further, an example of a press-fit pin is shown in FIG. 1, and since the terminal portion 1 in FIG. 1 makes elastic contact with other electronic components, it is required to have spring properties.

Since the terminal portion 3 is subjected to wire wrapping connection (solderless wrapping connection), it is required to have sufficient strength to withstand the rigors of this connection process.

In order to satisfy the required strength and springiness of each of these parts, phosphor bronze and the like have conventionally been considered as copper alloys for press fit pins. However, when this is press-molded into a press-fit pin, the hardness of the joint portion 2 increases rapidly, reaching a hardness of 280 to 290) in the case of plain bronze, which is the limit for a shape that is subject to heavy working.

For this reason, cracks occur with materials that are highly work-hardened, and since a large amount of force is required when inserting such a strongly worked joint into a metal hole in a printed board, terminals with low hardness are This resulted in the problem of deformation.

For this reason, it was considered to make the material very soft, but this resulted in problems such as insufficient strength, sticking of the die during pressing, and severe wear and tear on the mold.

For the above reasons, the phosphor bronze mentioned above was not sufficient as a material for press fit pins, and a material was required that had a certain degree of strength, springiness, good workability, and a small amount of work hardening. .

The present invention is the result of research conducted in view of these points.

We have found a copper alloy for press-fit pins that has strength, spring properties, good workability, and low work hardening.

(Structure of the invention) The present invention has an N i of 0.4 to 4. Ow t%, Sin, 1
A steel alloy for press-fit pins, characterized in that it contains ~1.0 wt%, the balance is Cu and unavoidable impurities, and has a hardness of Hv 160 to 200 after aging treatment. and Ni0.4-4.0wt%, Sin, 1-1.0w
Contains t%, and further contains P, Sn, As, Cr, as subcomponents.
Mg, Mn, Sb, Fe, Go, Al, Ti, Zr,
Be, Zn.

B, lanthanoid elements each 0. The total amount of one or two or more types from 1 to 1.0 wt% of OO is 0.001 to 2.0 wt%. Ow
t%, the balance consists of Cu and unavoidable impurities,
This is a copper alloy for press fit pins, characterized by a hardness of 160 to 200 Hv after aging treatment.

The reason why the amount of Ni added was set to 0.4 to 4.0 wt% is 0.4 to 4.0 wt%.
This is because if Si is less than 4 wt%, no improvement in strength will be observed even if 0.1 wt% or more of Si is added, and if it exceeds 4.0 wt%, conductivity and workability will decrease. The amount of Si added was set to 0.
The reason for setting it to 1 to 1.0 wt% is that the amount of Si is 0.1 wt%.
This is because if the Ni content is less than 0.4 wt%, a material with high strength and high conductivity cannot be obtained, and if it exceeds 1.0 wt%, the workability decreases and the conductivity deteriorates significantly. . Furthermore, as subcomponents P-3n, As, Cr, Mg
, Mn, Sn, Fe, Go.

The reason why one or more of Al, Ti, Zr, Be, Zn, B, and lanthanoid elements are added in a total amount of 0.001 to 2.0 wt% is as follows.
By adding these elements, the purpose is to improve the springiness 1 strength, but the total amount of addition is 0.001
If it is less than wt%, no improvement in spring properties or strength is observed.2.
This is because if it exceeds 0 wt%, the springiness and strength will improve, but the electrical conductivity will drop significantly.

The reason why the hardness after aging treatment is set to Hv 160 to 200 is that by aging the present alloy, the springiness and strength are significantly improved, and the degree of work hardening is also reduced. However, considering the amount of work hardening for press fit,
It is necessary to control the HV within the range of 160 to 200 by aging treatment.

This is because if the Hv is less than 160, the die will stick severely during pressing, and if it exceeds Hv200, mold wear will begin to occur due to the hardness, and cracks will begin to occur. Preferably Hv170-190 is recommended.

(Effects) As described above, when a press-fit pin is manufactured using the alloy of the present invention, it has excellent strength and spring properties, and there is no cracking or die wear during pressing, and the amount of work hardening is also very small. This eliminates the conventional drawback that the terminal portion deforms when press-fitted into the hole of the printed circuit board. Furthermore, the conductivity of this alloy becomes good when subjected to aging treatment, so that the alloy of the present invention can be said to be the best copper alloy that is excellent in all respects as an alloy for press-fit pins.

Next, the alloy of the present invention will be explained using examples.

(Example) Ni1.6wt%, Si0.38wt%, Zn0.42
An ingot consisting of w1:%, balance Cu was produced by normal atmospheric melting, and after hot rolling at 800°C, cold rolling and annealing were repeated to obtain a cold rolled plate with a thickness of 0.3o11. The hardness at this point was Hv 142. This cold rolled plate was subjected to aging treatment at 450°C for 2 hours to produce a material with Hv185.

For comparison, the Hv of a cold rolled plate with a thickness of 0.3 m
142 as is, and also those with Hv 176 that were aged to Hv 210 were also manufactured. Furthermore, C5210 (phosphor bronze for springs) and C51 are comparative alloys.
01 (Phosphor bronze type 1).

C7710 (nickel silver for springs) was used.

These samples were processed into press-fit pins as shown in FIGS. 1 and 2. In addition, in this figure, the degree of machining is 80% or more in the part that undergoes heavy machining.

About parts processed into pins during press processing ■ Hardness of part B in Figure 2 before and after processing.

■ Spring limit value of the spring part (1 in Figure 1).

■ Presence or absence of cracks (visual inspection); ■ Number of times one mold can be pressed (number of strokes); the results are shown in Table 1.

As can be seen from Table 1, the alloy of the present invention has no cracking or mold wear during press working, and exhibits excellent strength and spring properties. Further, the work hardening curves of various alloys are shown in Figures 3 to 6, and as can be seen from the differences in hardness before and after pressing in these figures and Table 1, the alloy of the present invention is There are very few differences due to the difference in color, making it possible to manufacture uniform products.

Margin below Table 1

[Brief explanation of drawings]

Figure 1 is a perspective view showing an example of a press-fit pin, Figure 2 is a sectional view taken along A'-'A in Figure 1, Figure 3 is a diagram showing the work hardening curve of the alloy of the present invention, and Figure 4 is a comparison. It is an alloy. C52
Figure 5 is a diagram showing the work hardening curve of C:5101, which is a comparative alloy, and Figure 6 is a diagram showing the work hardening curve of C7701, which is a comparative alloy.

Claims (2)

[Claims] (1) Ni0.4-4.0wt%, Si0.1-1.0
wt%, the balance consists of Cu and unavoidable impurities,
A copper alloy for press-fit pins, which has a hardness of 160 to 200 Hv after aging treatment. (2) Ni0.4-4.0wt%, Si0.1-1.0
Contains wt%, and further contains P, Sn, As, Cr as subcomponents.
, Mg, Mn, Sb, Fe, Co, Al, Ti, Zr,
Be, Zn, B, lanthanoid elements each 0.001 to 1.
One or more types from 0 wt% in total amount of 0.00
A copper alloy for press-fit pins, characterized in that it contains 1 to 2.0 wt%, the balance is Cu and unavoidable impurities, and has a hardness of Hv 160 to 200 after aging treatment.