Rail vehicle axle

1. A rail vehicle axle comprising:

a chemical composition consisting of, in mass %,

C: 0.20 to 0.35%,

Si: 0.20 to 0.65%,

Mn: 0.40 to 1.20%,

P: 0.020% or less,

S: 0.020% or less,

Sn: 0.21 to 0.40%,

N: 0.0200% or less,

Cu: 0 to 0.30%,

Ni: 0 to 0.30%,

Al: 0 to 0.100%,

V: 0 to 0.060%, and

one or more from the group consisting of Cr: more than 0.20 to 0.30%, Mo: 0.005 to 0.08%, and Ti: 0.002 to 0.020%, with the balance being Fe and impurities, and satisfying Formulae (1) and (2):

0.58≤C+Si/8+Mn/5+Cu/10+Cr/4+V≤0.67  (1)

Si+0.9Cr≥0.60  (2)

where each element symbol in Formulae (1) and (2) is substituted by the content (mass %) of a corresponding element,

wherein the smooth fatigue limit is more than 270 MPa,

the notched fatigue limit is more than 195 MPa, and

a notch factor of the rail vehicle axle is not more than 1.47, where notch factor is defined by smooth fatigue limit divided by notched fatigue limit.

2. The rail vehicle axle according to claim 1 , wherein

the chemical composition contains one or more selected from the group consisting of:

Cu: 0.01 to 0.30%, and

Ni: 0.01 to 0.30%.

3. The rail vehicle axle according to claim 1 , wherein

the chemical composition contains one or more selected from the group consisting of:

Al: 0.005 to 0.100%, and

V: 0.005 to 0.060%.

4. The rail vehicle axle according to claim 2 , wherein

the chemical composition contains one or more selected from the group consisting of:

Al: 0.005 to 0.100%, and

V: 0.005 to 0.060%.