Steel parts excellent in rolling contact fatigue properties

摘要

To provide a steel component having high surface hardness exceeding 800 HV, and capable of exhibiting excellent rolling fatigue characteristics even under an environment where a foreign matter such as abrasion powder may be mixed.SOLUTION: A steel component includes C:0.50 to 1.20%, Si:0.20 to 1.50%, Mn:0.20 to 1.50%, Cr:5.00 to 9.00%, Mo:0 to 1.00% (including 0%), V:0 to 1.00% (including 0%), and the balance made of Fe and inevitable impurities, and has a surface hardened layer. The surface characteristics satisfy (a) a retained austenite amount of 20 to 50% by area rate, (b) the major axis length of the maximum nitride of 15 μm or smaller, (c) the number of carbon nitride having a circle equivalent diameter of 0.1 to 2.0 μm of 400,000/mmor larger, (d) Cs of 1.5 to 3.4%, (e) Ns of 0.5% or smaller, and (f) the surface hardness exceeding 800 HV. Furthermore, the formula 1: 4×([Cs]+[Ns])-([Cr]+[Mo]+[V])<3, 6 is satisfied.SELECTED DRAWING: None