Method for producing steel component

1. A method for producing a steel component by performing the treatments of the following sequentially steps 1 and 2 to a steel material containing, by mass %,

C: 0.15 to 0.25%,

Si: 0.01 to 0.10%,

Mn: 0.50 to 0.80%,

S: 0.003 to 0.030%,

Cr: 0.80 to 1.20%,

Mo: 0.30 to 0.45%,

Al: 0.015 to 0.050%, and

N: 0.010 to 0.025%, wherein

fn represented by Formula (1) shown below is 1.3 to 2.4, the balance being Fe and impurities, and contents of P and O among the impurities are

P: not more than 0.010%, and

O: not more than 0.0020%:

step 1: a treatment which holds the steel material at a temperature of 850 to 1000° C. in a carburizing atmosphere or carbonitriding atmosphere, and

step 2: a treatment which quenches the carburized or carbonitrided steel material, by using quenching oil having a temperature of 40 to 80° C. and a kinetic viscosity of 20 to 25 mm 2 /s at 40° C.;

fn =Cr/Mn  (1)

where, Cr and Mn in Formula (1) represent the content of each element in mass %.

2. The method for producing a steel component according to claim 1 , wherein the step 1 includes a holding process at a temperature of 850 to 1000° C. in a carburizing atmosphere or carbonitriding atmosphere followed by a holding process at a temperature of 800 to 900° C. in a carburizing atmosphere or carbonitriding atmosphere.

3. The method for producing a steel component according to claim 1 , wherein the steel material contains, in mass %, Nb: not more than 0.08% in lieu of a part of Fe.