Co-Ni-base alloy

Abstract

A Co—Ni-base alloy, being characterized in that a composition of the alloy comprises at least Co, Ni, Cr, Mo, W and Fe, and percentages by weight of the composition are from 25% to 45% of Co, from 25% to 40% of Ni, from 18% to 26% of Cr, from 3% to 11% of Mo, from 0.5% to 9% of W, wherein a sum of Mo and W is from 4% to 13% by weight, and from 1.1% to 5% of Fe.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Co—Ni-base alloy, and, more particularly to a Co—Ni -base alloy having a high elasticity and a high corrosion resistance for use in a small-size precision device and the like, a mainspring using the Co—Ni-base alloy, and a method for producing the mainspring. 2. Description of the Related Art To date, a Co-base alloy, a Co—Ni-base alloy which is more efficient than the Co-base alloy or the like has been used as a high elastic material for use in a small-size precision device (for example, refer to patent document 1). Further, since a high output torque, durability and corrosion resistance are required for a mainspring of a wrist-watch, the Co-base alloy or the Co—Ni-base alloy which is high in Young's modulus or material strength, excellent in corrosion resistance and has a favorable plastic workability has been used as a material for the mainspring. The Young's modulus of the Co-base alloy...

AI Technical Summary

Benefits of technology

Preferably, a processing ratio of the cold-wire-drawing is 10% or more in terms of a reduction ratio in a cross-section area. Further, the age-hardening treatment is preferably performed at a treating temperature of from 400° C. to 700° C. in a vacuum or non-oxidation atmosphere.

The Co—Ni-base alloy according to the present invention is enhanced in a material strength compared with the conventional Co—Ni-base alloy. For this account, it is effective to use the Co—Ni-base alloy according to the invention for the spring or the like for the precision device which requires high load, high reliability and high corrosion resistance and, therefore, it has an advantage such that it can correspond to a trend of down-sizing and being free of maintenance thereof and the like. By processing the Co—Ni-base alloy according to the invention, the mainspring having a high output torque, an excellent durability and corrosion resistance can be obtained. When the mainspring according to the invention is used as a power source of the wrist-watch, since a large driving torque can be obtained without enlarging thickness or width thereof, it is possible to increase a moment of inertial of a balance wheel, thereby being capable of decreasing a change of a rate to be caused by a vibration or a shock. Further, diversification of added mechanisms or an increase of duration period of time can be realized. Still further, even when it is repeatedly used, since characteristics thereof are hardly deteriorated, the high output torque can be maintained. It is tough and is hardly broken. Furthermore, even when it is left in a humid environment caused by, for example, a climate, a human perspiration or the like, it performs a high corrosion resistance.

Problems solved by technology

Along with a performance enhancement of a mechanical wrist-watch or a diversification of added mechanisms thereof, a higher output torque has been required for a mainspring which is an energy source, and there is a problem in that a conventional mainspring is insufficient.

However, a space within the mechanical wrist-watch is limited and, accordingly, it is not advantageous to increase thickness or width of the spring.

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