| 摘要 |
PROBLEM TO BE SOLVED: To provide steel wire for spring in which high fatigue resistance and corrosion fatigue resistance can be obtained by strengthening the crystal grains of parent phase martensite, its production method, and a spring. SOLUTION: The steel wire has chemical components containing, by mass, 0.4 to 1.0% C, 0.1 to 2.5% Si, 0.2 to 1.2% Mn and 0.5 to 1.2% Cr, and the balance Fe with inevitable impurities. The steel wire has a tempered martensitic structure obtainable by mainly performing quenching and tempering. Then, as for the shape of carbides in the martensitic crystals, the average aspect ratio is >=3.0. By acicularly precipitating carbides in the crystal grains, the carbides play a role as reinforcing fibers, and make the crystal grains into the extremely firm ones having toughness, so that its fatigue resistance improves.
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