Non-heat treated steel for induction hardening
A non-heat treated steel for induction hardening contains, in mass %, C: 0.35 to 0.44%, Si: 0.01 to less than 0.30%, Mn: 0.80 to 1.50%, P: 0.030% or less, S: more than 0.010 to 0.095%, Cr: more than 0.10 to 0.30%, V: 0.050 to 0.200%, N: 0.0040 to 0.0200%, O: 0.0024% or less, Cu: 0.05% or less and Ni: 0.05% or less, and for which fn1≤50.0, fn2: 0.70 to 1.00, and fn3≥1.30. In the steel, a ratio of a number of Mn oxides containing oxygen in an amount of 20.0 mass % or more and Mn in an amount of 10.0 mass % or more to the number of oxides is 10.0% or less fn 1=80C 2 +55C+13Si+4.8Mn+30P+30S+1.5Cr fn 2=C+(Si/10)+(Mn/5)−(5S/7)+(5Cr/22)+1.65V fn 3=−2C—Si+2.33Mn+0.26Cr+V−1.5Cu−1.5Ni.
1. A non-heat treated steel for induction hardening, consisting of, in mass %,
C: 0.35 to 0.44%,
Si: 0.01 to less than 0.30%,
Mn: 0.80 to 1.50%,
P: 0.030% or less,
S: more than 0.010 to 0.095%,
Cr: more than 0.10 to 0.30%,
V: 0.050 to 0.200%,
N: 0.0040 to 0.0200%,
O: 0.0024% or less,
Cu: 0.05% or less,
Ni: 0.05% or less,
Al: 0 to 0.040%,
Ti: 0 to 0.020%,
Nb: 0 to 0.020%,
Pb: 0 to 0.30%,
Ca: 0 to 0.0100%,
Mo: 0 to 0.20%,
fn1 defined by Formula (1) being 50.0 or less,
fn2 defined by Formula (2) being 0.70 to 1.00,
fn3 defined by Formula (3) being 1.30 or more, and
the balance being Fe and impurities,
wherein oxides are defined as inclusions containing oxygen in an amount of 20.0 mass % or more, and, among the oxides, Mn oxides are defined as inclusions containing oxygen in an amount of 20.0 mass % or more and Mn in an amount of 10.0 mass % or more, and a ratio of a total number of the Mn oxides with respect to a total number of the oxides is 10.0% or less;
fn 1=80C 2 +55C+13Si+4.8Mn+30P+30S+1.5Cr (1)
fn 2=C+(Si/10)+(Mn/5)-(5S/7)+(5Cr/22)+1.65V (2)
fn 3=−2C-Si+2.33Mn+0.26Cr+V-1.5Cu-1.5Ni (3)
where a content in mass % of a corresponding element is substituted for each symbol of an element in Formula (1) to Formula (3).
2. The non-heat treated steel for induction hardening according to claim 1 , having:
Al: 0.005 to 0.040%.
3. The non-heat treated steel for induction hardening according to claim 1 , having:
Ti: 0.005 to 0.020%, and/or
Nb: 0.005 to 0.020%.
4. The non-heat treated steel for induction hardening according to claim 1 , having:
Pb: 0.10 to 0.30%, and/or
Ca: 0.0010 to 0.0100%.
5. The non-heat treated steel for induction hardening according to claim 1 , having:
Mo: 0.05 to 0.20%.
6. The non-heat treated steel for induction hardening according to claim 2 , having:
Ti: 0.005 to 0.020%, and/or
Nb: 0.005 to 0.020%.
7. The non-heat treated steel for induction hardening according to claim 2 , having:
Pb: 0.10 to 0.30%, and/or
Ca: 0.0010 to 0.0100%.
8. The non-heat treated steel for induction hardening according to claim 2 , having:
Mo: 0.05 to 0.20%.
9. The non-heat treated steel for induction hardening according to claim 3 , having:
Pb: 0.10 to 0.30%, and/or
Ca: 0.0010 to 0.0100%.
10. The non-heat treated steel for induction hardening according to claim 3 , having:
Mo: 0.05 to 0.20%.
11. The non-heat treated steel for induction hardening according to claim 4 , having:
Mo: 0.05 to 0.20%.
12. The non-heat treated steel for induction hardening according to claim 6 , having:
Pb: 0.10 to 0.30%, and/or
Ca: 0.0010 to 0.0100%.
13. The non-heat treated steel for induction hardening according to claim 6 , having:
Mo: 0.05 to 0.20%.
14. The non-heat treated steel for induction hardening according to claim 7 , having:
Mo: 0.05 to 0.20%.
15. The non-heat treated steel for induction hardening according to claim 9 , having:
Mo: 0.05 to 0.20%.
16. The non-heat treated steel for induction hardening according to claim 12 , containing having:
Mo: 0.05 to 0.20%.