Patent ID: 11965231
Assignee: JTEKT CORPORATION
Field: Materials, metallurgy (Chemistry)
Classification: CPC C  Y | IPC C

Claim 0:
1. A steel material comprising a chemical composition consisting of, in mass %:
C: 0.15 to 0.45%,
Si: 0.50% or less,
Mn: 0.20 to 0.60%,
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,
Cu: 0 to 0.20%,
Ni: 0 to 0.20%,
B: 0 to 0.0050%,
Nb: 0 to 0.100%,
Ti: 0 to 0.100%,
Ca: 0 to 0.0010%, and
the balance being Fe and impurities, and
satisfying Formula (1) to Formula (4),
wherein, in its microstructure, a total area fraction of ferrite and pearlite is 10.0% or more, and the balance is bainite, and
a proportion of a content of V (mass %) in electrolytic extraction residue to the content of V (mass %) in the chemical composition is 10.0% or less:

1.50<0.4Cr+0.4Mo+4.5V<2.45  (1)

2.20<2.7C+0.4Si+Mn+0.45Ni+0.8Cr+Mo+V<2.80  (2)

Mo/V≥0.58  (3)

(Mo+V+Cr)/(Mn+20P)≥2.40  (4)

where each symbol of an element in Formula (1) to Formula (4) is to be substituted by a content of a corresponding element (mass %).