Steel wire
A steel wire which has excellent cold coiling workability, and which has an excellent fatigue limit when made into a spring is provided. A chemical composition of the steel wire according to the present, embodiment containing, in mass %, C: 0.50 to 0.80%, Si: 1.20 to less than 2.50%, Mn: 0.25 to 1.00%, P: 0.020% or less, S: 0.020% or less, Cr: 0.40 to 1.90%, V: 0.05 to 0.60%, and N: 0.0100% or less, with the balance being Fe and impurities. In the steel wire, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 5000 to 80000 pieces/μm 3 .
1 . A steel wire having a chemical composition containing, in mass %,
C: 0.50 to 0.80%,
Si: 1.20 to less than 2.50%,
Mn: 0.25 to 1.00%,
P: 0.020% or less,
S: 0.020% or less,
Cr: 0.40 to 1.90%,
V: 0.05 to 0.60%,
N: 0.0100% or less,
Ca: 0 to 0.0050%,
Mo: 0 to 0.50%,
Nb: 0 to 0.050%,
W: 0 to 0.60%,
Ni: 0 to 0.500%,
Co: 0 to 0.30%,
B: 0 to 0.0050%,
Cu: 0 to 0.050%,
Al: 0 to 0.0050%,
Ti: 0 to 0.050%, and
with the balance being Fe and impurities,
wherein a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 5000 to 80000 pieces/μm 3 .
2 . The steel wire according to claim 1 , wherein:
the chemical composition contains:
Ca: 0.0001 to 0.0050%, and
when, among inclusions,
inclusions in which, in mass %, an O content is 10.0% or more are defined as oxide-based inclusions,
inclusions in which, in mass %, an S content is 10.0% or more and the O content is less than 10.0% are defined as sulfide-based inclusions, and
among the sulfide-based inclusions, inclusions in which, in mass %, a Ca content is 10.0% or more, the S content is 10.0% or more, and the O content is less than 10.0% are defined as Ca sulfides,
a numerical proportion of the Ca sulfides with respect to a total number of the oxide-based inclusions and the sulfide-based inclusions is 0.20% or less.
3 . The steel wire according to claim 1 wherein: the chemical composition contains one or more types of element selected from the group consisting of:
Mo: 0.01 to 0.50%,
Nb: 0.001 to 0.050%,
W: 0.01 to 0.60%,
Ni: 0.001 to 0.500%,
Co: 0.01 to 0.30%, and
B: 0.0001 to 0.0050%.
4 . The steel wire according to claim 2 , wherein:
the chemical composition contains one or more types of element selected from the group consisting of:
Mo: 0.01 to 0.50%,
Nb: 0.001 to 0.050%,
W: 0.01 to 0.60%,
Ni: 0.001 to 0.500%,
Co: 0.01 to 0.30%, and
B: 0.0001 to 0.0050%.
5 . The steel wire according to claim 1 , wherein:
the chemical composition contains one or more types of element selected from the group consisting of:
Cu: 0.001 to 0.050%,
Al: 0.0001 to 0.0050%, and
Ti: 0.001 to 0.050%.
6 . The steel wire according to claim 2 , wherein:
the chemical composition contains one or more types of element selected from the group consisting of:
Cu: 0.001 to 0.050%,
Al: 0.0001 to 0.0050%, and
Ti: 0.001 to 0.050%.
7 . The steel wire according to claim 3 , wherein:
the chemical composition contains one or more types of element selected from the group consisting of:
Cu: 0.001 to 0.050%,
Al: 0.0001 to 0.0050%, and
Ti: 0.001 to 0.050%.
8 . The steel wire according to claim 4 , wherein:
the chemical composition contains one or more types of element selected from the group consisting of:
Cu: 0.001 to 0.050%,
Al: 0.0001 to 0.0050%, and
Ti: 0.001 to 0.050%.