Spring steel wire and spring
A spring steel wire includes, by mass %, C: 0.40% to 0.75%, Si: 1.00% to 5.00%, Mn: 0.20% to 2.00%, P: 0.0001% to 0.0500%, S: 0.0001% to 0.0500%, Cr: 0.50% to 3.50%, Al: 0.0005% to 0.0500%, N: 0.0020% to 0.0100%, Mo: 0% to 2.00%, V: 0% to 0.50%, W: 0% to 0.50%, Nb: 0% to 0.100%, Ti: 0% to 0.100%, Ca: 0% to 0.0100%, Mg: 0% to 0.0100%, Zr: 0% to 0.1000%, B: 0% to 0.0100%, Cu: 0% to 1.00%, Ni: 0% to 3.00%, and a remainder consisting of Fe and impurities. A structure includes, by area radio, tempered martensite of 90% or more. The prior austenite grain size number is No. 12.5 or higher. The presence density of iron-based carbide having an equivalent circle diameter ranging from 0.15 μm to 0.50 μm ranges from 0.40 pieces/μm 2 to 2.00 pieces/μm 2 .
1. A spring steel wire comprising, by mass %,
C: 0.40% to 0.75%,
Si: 1.00% to 5.00%,
Mn: 0.20% to 2.00%,
P: 0.0001% to 0.0500%,
S: 0.0001% to 0.0500%,
Cr: 0.50% to 3.50%,
Al: 0.0005% to 0.0500%,
N: 0.0020% to 0.0100%,
Mo: 0% to 2.00%,
V: 0% to 0.50%,
W: 0% to 0.50%,
Nb: 0% to 0.100%,
Ti: 0% to 0.100%,
Ca: 0% to 0.0100%,
Mg: 0% to 0.0100%,
Zr: 0% to 0.1000%,
B: 0% to 0.0100%,
Cu: 0% to 1.00%,
Ni: 0% to 3.00%, and
a remainder of Fe and impurities,
wherein a structure includes, by area ratio, a tempered martensite of 90% or more,
wherein a prior austenite grain size number is No. 13.5 or higher, and
wherein a presence density of iron-based carbide having an equivalent circle diameter ranging from 0.15 μm to 0.50 μm is 1.03 pieces/μm 2 to 2.00 pieces/μm 2 .
2. The spring steel wire according to claim 1 ,
wherein the spring steel wire includes, by mass %, at least one of
Mo: 0.01% to 2.00%,
V: 0.01% to 0.50%,
W: 0.01% to 0.50%,
Nb: 0.005% to 0.100%, and
Ti: 0.001% to 0.100%.
3. A spring including the spring steel wire according to claim 2 .
4. The spring steel wire according to claim 2 ,
wherein the spring steel wire includes, by mass %, at least one of
Ca: 0.0002% to 0.0100%,
Mg: 0.0002% to 0.0100%,
Zr: 0.0005% to 0.1000%,
B: 0.0005% to 0.0100%,
Cu: 0.05% to 1.00%, and
Ni: 0.05% to 3.00%.
5. A spring including the spring steel wire according to claim 4 .
6. The spring steel wire according to claim 1 ,
wherein the spring steel wire includes, by mass %, at least one of
Ca: 0.0002% to 0.0100%,
Mg: 0.0002% to 0.0100%,
Zr: 0.0005% to 0.1000%,
B: 0.0005% to 0.0100%,
Cu: 0.05% to 1.00%, and
Ni: 0.05% to 3.00%.
7. A spring including the spring steel wire according to claim 6 .
8. A spring including the spring steel wire according to claim 1 .