| 摘要 |
PROBLEM TO BE SOLVED: To provide a low-cost piano wire spring which has high strength, and excellent fatigue strength, settling resistance, heat resistance, or the like. SOLUTION: The piano wire spring is obtained by subjecting a piano wire rod having a composition containing, by mass, 0.8 to 0.85% C, 0.8 to 1.0% Si, 0.6 to 0.9% Mn, <=0.025% P, <=0.025% S and <=0.2% Cu, and the balance Fe with inevitable impurities to cold forming and annealing. By using the piano wire rod in which the content of Si has been increased, the piano wire rod having high strength and excellent heat resistance, or the like, can be obtained at a relatively low cost.
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