| 摘要 |
PROBLEM TO BE SOLVED: To provide a case-hardened steel excellent in fatigue strength property, and a production method thereof.SOLUTION: The case-hardened steel is provided which has a component composition containing C:0.10 to 0.40 mass%, Si:0.01 to 1.20 mass%, Mn:0.30 to 1.50 mass%, P:0.1 mass% or less, S:0.5 mass% or less, Cr:0.40 to 2.00 mass%, Al:0.010 to 0.080 mass%, N:0.05 mass% or less and the balance Fe with inevitable impurities, and in which area A (μm) of each of an oxide-based inclusion and a nitride-based inclusion positioned in a fish eye center portion obtained by observing a fracture surface after rotating bending fatigue test by a microscope satisfies √A≤100 (μm).SELECTED DRAWING: Figure 4 |
