| 摘要 |
High cleanliness spring steel useful in manufacturing a spring with SiO2-based inclusions being extremely controlled and excellent in fatigue properties is provided.;High cleanliness spring steel which is steel containing;
C: 1.2% (means mass %, hereafter the same with respect to the component) or below (not inclusive of 0%),Si: 1.2-4%,Mn: 0.1-2.0%,Al: 0.01% or below (not inclusive of 0%),
and the balance comprising iron with inevitable impurities, wherein;
the total of oxide-based inclusions of 4 or above of L (the large diameter of an inclusion)/D (the short diameter of an inclusion) and 25 μm or above of D and oxide-based inclusions of less than 4 L/D and 25 μm or above of L, in the oxide-based inclusions of 25 mass % or above of oxygen concentration and 70% (means mass %, hereafter the same with respect to inclusions) or above of SiO2 content when Al2O3 +MgO+CaO+SiO2+MnO=100% is presumed, out of inclusions in the steel, is 20 nos./500 g or below. |
