Railway axle

A railway axle, comprising:

• a pair of fitting portions, on each of which a railway wheel is to be press-fitted, and
• a center parallel portion located between the pair of fitting portions, wherein:
• the fitting portion includes:
• a fitting portion hardened layer formed in an outer layer of the fitting portion, and
• a base metal portion located inward of the fitting portion hardened layer;
• the center parallel portion includes:
• a center parallel portion hardened layer formed in an outer layer of the center parallel portion, and
• the base metal portion located inward of the center parallel portion hardened layer;
• the base metal portion consists of, in mass %,
• C:
• 0.22 to 0.29%,
• Si:
• 0.15 to 0.40%,
• Mn:
• 0.50 to 0.80%,
• P:
• 0.020% or less,
• S:
• 0.040% or less,
• Cr:
• 0.90 to 1.20%,
• Mo:
• 0.15 to 0.30%,
• N:
• 0.0200% or less,
• O:
• 0.0040% or less,
• Ca:
• 0 to 0.0010%,
• Cu:
• 0 to 0.30%,
• Ni:
• 0 to 0.30%,
• Al:
• 0 to 0.100%,
• V:
• 0 to 0.060%,
• Ti:
• 0 to 0.020%,
• Nb:
• 0 to 0.030%, and
• B:
• 0 to 0.0050%,
• with the balance being Fe and impurities;
• and
• in a region having the Vickers hardness of 480 HV or more in the center parallel portion hardened layer,
• a dislocation density ρ obtained based on a CoKα characteristic X-ray diffraction result is 2.5×1016 m−2 or less,
• a half-value width B of a (211) diffraction plane measured by CoKα characteristic X-ray diffraction is 1.34 degrees or less, and
• the dislocation density ρ obtained based on a CoKα characteristic X-ray diffraction result, and the half-value width B of a (211) diffraction plane measured by CoKα characteristic X-ray diffraction satisfy Formula (1):
• (−4.8×1016×B+8.5×1016)/ρ≥1.00 (1)
• wherein, in Formula (1), ρ is the dislocation density in m−2 obtained based on a CoKα characteristic X-ray diffraction result, and B is the half-value width in degrees of a (211) diffraction plane measured by CoKα characteristic X-ray diffraction.