Carburized bearing

A carburized bearing comprising:

• a carburized layer formed in an outer layer of the carburized bearing;
• and
• a core portion inner than the carburized layer, wherein
• the core portion comprises, in mass %:
• C:
• 0.25 to 0.45%,
• Si:
• 0.10 to 0.50%,
• Mn:
• 0.40 to 0.70%,
• P:
• 0.015% or less,
• S:
• 0.005% or less,
• Cr:
• 0.80 to 1.50%,
• Mo:
• 0.17 to 0.30%,
• V:
• 0.24 to 0.40%,
• Al:
• 0.005 to 0.100%,
• N:
• 0.0300% or less,
• O:
• 0.0015% or less, and
• the balance being Fe and impurities, and
• on a precondition that a content of each element of the core portion falls within a range described above, Formula (1) to Formula (4) are satisfied, wherein
• a concentration of C of a surface of the carburized bearing is, in mass %, 0.70 to 1.20%,
• a Rockwell hardness C scale HRC of the surface of the carburized bearing is 58.0 to 65.0,
• the carburized bearing contains a plurality of CaO—CaS—MgO—Al2O3 composite oxides containing:
• at least one selected from the group consisting of CaO and CaS,
• MgO, and
• Al2O3,
• a proportion of a total area of the CaO—CaS—MgO—Al2O3 composite oxides with respect to a total area of oxides in the carburized bearing is 30.0% or more;
• and
• wherein the carburized bearing comprises oxides and among oxides in the carburized bearing, a number density of oxides having an equivalent circle diameter of 20.0 μm or more is 0.1 to no more than 15.0 pieces/mm2:
• 1.50<0.4Cr+0.4Mo+4.5V<2.45 (1)
• 2.20<2.7C+0.4Si+Mn+0.45Ni+0.8Cr+Mo+V<3.50 (2)
• Mo/V≥0.58 (3)
• (Mo+V+Cr)/(Mn+20P)≥2.00 (4)
• where each symbol of an element in Formula (1) to Formula (4) is to be substituted by a content of a corresponding element in mass %, and is to be substituted by “0” if the corresponding element is not contained.