JPS61170534A - Electrically conductive spring material - Google Patents

Abstract

PURPOSE:To reduce the cost of an electrically conductive spring material and to improve the mechanical strength by adding prescribed percentages of Ni, Be, Si, Co, Fe, Zr, Ti and Mg to Cu. CONSTITUTION:An electrically conductive spring material is obtd. by adding 0.01-2wt% in total of one or more among 0.01-1wt% each of Co, Fe, Zr, Ti and Mg as secondary components to a Cu alloy consisting of 1.8-3wt% Ni, 0.15-0.3wt% Be, 0.4-1.2wt% Si and the balance Cu.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a low-cost conductive spring material with excellent conductivity and spring properties that is used as a material for electrical equipment such as connectors, switches, and relays.

(Prior art) Typical conductive spring materials with excellent conductivity and spring properties are 5.5 to 9.0% (weight %, hereinafter referred to as 5.5% to 9.0% by weight, which is defined as Type 2 or Type 3 in JIS). Same) Sn and 0.0
Although phosphor bronze contains 3 to 0.3% P, its conductivity, bending formability, stress relaxation properties, etc. are insufficient for use in recent miniaturized electronic components that require high reliability. Demand for improvements is increasing for a number of reasons. In addition, one of the conductive spring materials that satisfies these requirements is an alloy with a nominal composition of Cu-0.4%Be-1.8%NN, but since Be is expensive, the material cost is high. There was a drawback. (For example, JP-A-53-14
(Publication No. 612) (Problems to be solved by the invention) The present invention solves the conventional problems as described above, and
u -0.4% B e -1.8% This was completed with the aim of providing a conductive spring material with excellent cost performance by reducing the cost and e while maintaining the excellent characteristics of the alloy. It is.

(Means for Solving the Problems) The present invention is characterized by a mass ratio of 1.8 to 3.0% by weight and 0.1% by weight.
5-0.35% Be, 0.4-1.2% Si,
In an alloy consisting of the balance Cu and unavoidable impurities, G o: 0.01 to 1.0%, Fe: 0 as subcomponents.
゜01~1.0%, Zr: 0.01~1.0%,
Ti: 0.01-1.0%, Mg: 0.01-1
．． It is characterized in that one or more components selected from the group consisting of 0% are added in a total amount of 0.01 to 2.0%. That is, the present invention is capable of compensating for the decrease in strength caused by reducing the amount of Be to reduce the price by increasing the amount of Ni and adding Si, and that solution treatment, which is a problem in reducing the amount of Ba, can be compensated for by increasing the amount of Ni and adding Si. Grain growth when the Ni amount is 1.
that it can be effectively suppressed by setting it to 8 to 3.0%;
By adding St in the range of 0.4 to 1.2%, various properties such as stress relaxation properties, elongation, and bending formability can be improved. It was completed based on new knowledge that it is useful for grain refinement and further improvement of material strength, and the strength and spring characteristics of the present invention are equivalent to or higher than those of conventional phosphor bronze for springs. This has resulted in a low-cost conductive spring material that is particularly excellent in mechanical strength, bending formability, stress relaxation properties, and conductivity.

Next, to explain the reason for limiting the content of each alloy component, Ni
If it is less than 1.8%, coarsening of crystal grains during solution treatment due to the decrease in Be content cannot be prevented, so improvements in mechanical strength, elongation, and formability cannot be obtained, and if it exceeds 3.0%. In addition to not improving the properties commensurate with the increase in the amount added, it also inhibits the rolling workability and bending formability of the material, so the range of 1.8 to 3.0% is set, especially 2.0 to 2.8%. The range is optimal. If Be is less than 0.15%, precipitation hardenability decreases and coarsening of crystal grains during solution treatment cannot be prevented, and if it exceeds 0.35%, the effect of reducing material prices will be reduced, so it should be 0.15~ The content is set in the range of 0.35%, and the range of 0.20 to 0.25% is particularly optimal. S
i is an important component to compensate for the decrease in strength due to the decrease in Be content and improve elongation, formability, and stress relaxation properties;
．． If it is less than 4%, the effect is not noticeable, and if it exceeds 1.2%, the conductivity is significantly inhibited, so 0.4 to 1.2%.
In particular, a range of 0.4 to 1.0% is preferred. Furthermore, by adding St in a range of 0.4 to 1.2%, the castability, slag separation properties, and oxidation resistance of the alloy are greatly improved, which can also contribute to reducing manufacturing costs.

By adding CosFeSZrSTiSMg to the above alloy composition within the range of 0.01 to 1.0%, each contributes to grain refinement of the alloy and improvement of its mechanical strength. It is an ingredient. These components are 0
．． If it is less than 0.01%, no substantial effect is observed, and conversely, if it exceeds 1.0% alone or if the total amount exceeds 2.0%, the effect is saturated and it becomes disadvantageous in terms of material price. Moreover, it deteriorates elongation, moldability, etc.

(Example) Alloys of Examples 1 to 9 and Comparative Examples 1 to 9 shown in Table 1
8 alloy (Comparative Example 3 is the conventional Cu-0.4%B e-
1.8% Ni alloy, Comparative Example 8 is conventional phosphor bronze for springs)
was melted and cast in a high-frequency induction furnace, hot forged, hot rolled, annealed, and cold rolled repeatedly to obtain a 0°32mm plate.Next, as a final solution treatment, it was heated at 900°C for 5 minutes and then submerged in water. After cooling and further rolling by 37%,
Aging treatment was performed at 0° C. for 2 hours, and various properties were measured. The results are shown in Table 2, where the stress relaxation properties were determined by applying a maximum bending stress of 40 kg f/wm to the test piece.
After holding at 200°C for 100 hours, the load was released and the residual stress was measured, and the stress residual rate was evaluated. 0 Bending formability was evaluated by the ratio R/l of the minimum bending radius R that does not cause cranking and the plate thickness t. . In addition, 0° is the characteristic value in the rolling direction, 9
0° indicates the characteristic value in the direction perpendicular to the rolling direction.

Table 1 Alloy Composition (Weight %) (Effects of the Invention) As is clear from the explanation using the above examples, the present invention is advantageous in that the conventional Cu-0, which is expensive and has a content of e. The material cost is significantly lower than that of the 4%Bel-1.8%Ni alloy, and it also achieves high mechanical strength and stress relaxation properties equivalent to or higher than that of the 4%Bel-1.8%Ni alloy. Compared to the properties of the conventional phosphor bronze for springs shown, the moldability is particularly excellent in the 90° direction, and we have succeeded in obtaining extremely excellent characteristic values in terms of electrical conductivity and stress relaxation properties. Therefore, the present invention greatly contributes to the development of industry as an alloy with excellent cost performance that solves the problems of conventional conductive spring materials.

Claims (1)

[Claims] 1.8-3.0% Ni and 0.15-0.3% by weight
An alloy consisting of 5% Be, 0.4-1.2% Si, the balance Cu and unavoidable impurities, with Co: 0.01-1.0% and Fe: 0.01 as subcomponents. ~1.0%
, Zr: 0.01-1.0%, Ti: 0.01-1.0
%, Mg: 0.01 to 1.0% in total amount of one or more components selected from the group consisting of 0.01 to 2.0%.