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AssigneesThe Foundation: the Research Institute for Electric and Magnetic Materials, Seiko Instruments Inc.
InventorsYuetsu Murakami, Koichiro Jujo, Osamu Takahashi, Jun Tsuneyoshi, Ryo Sugawara, Takeshi Takano
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A constant-modulus alloy, which has a low saturation magnetic flux density to provide weakly magnetic properties, a high Young's modulus, a low temperature coefficient of Young's modulus, and high hardness, is provided. A hairspring, a mechanical driving apparatus and a watch and clock, in which the alloy is used, are provided. The alloy consists of Co, Ni, Cr, Mo. and Fe. The alloy is healed and cooled before being subjected to repeated wiredrawing and intermediate annealing, forming a wire with a fiber structure having a <111> fiber axis. The wire is then cold rolled into a sheet and heated to obtain optimal magnetic insensitivity and hardness.
A magnetically insensitive, highly hard, constant-modulus alloy, containing, by atomic weight ratio, 20-40% Co and 7 to 22% Ni, with the total of Co and Ni being 42.0 to 49.5%, 5 to 13% Cr and 1 to 6% Mo, with the total of Cr and Mo being 13.5 to 16.0%, and with the balance being essentially Fe (with the proviso that Fe is present 37% or more) and inevitable impurities, characterized in that the alloy has a {110}<111> texture, as well as a saturation magnetic flux density of 2500 to 3500 G, a temperature coefficient of Young's modulus of (−5˜+5)—10−5 degrees C.−1 of as measured at 0 to 40 degrees C., and a Vickers hardness of 350 to 550.
Dependencies are inferred from the claim text.