1966 年 15 巻 156 号 p. 595-601
Many investigations have been made to clarify the fatigue strength of piano wires in the air, but few investigations have so far been made of the fatigue strength under the corrosive condition. Wire ropes and power-transmission wires stretched over the sea are exposed to the sun, rain and sea-breeze. The wire ropes used in manufacturing districts or coal-mining areas are exposed to the sun, smog and rain too. It is inferred accordingly that they suffer from the corrosion fatigue too. It is one of the most important problems what the characteristic of piano wires is and that of power-transmission wires is each with respect to the corrosion fatigue.
This paper gives some results of the corrosion fatigue tests made on piano wires of 0.85% carbon content by spraying hard water on them, and of the measurement of their natural electropotential.
It is clarified as the result, that the fatigue strength of the piano wires subjected to corrosion is much lower than that in the piano wires left in the air. In the air, the endurance limit of piano wires drawn and blue-hardened after drawing increases with the total reduction and takes the maximum value when the total reduction reaches about 75%. While the fatigue strength of piano wires decreases with the total reduction when hard water is sprayed over them. This may be affected by the value of the electro-potential of piano wires. The value of the electro-potential of piano wires blue-hardened after drawing is higher than that of piano wires drawn.