Patent ID: 11952668
Assignee: NIPPON STEEL CORPORATION
Field: Materials, metallurgy (Chemistry)
Classification: CPC C | IPC C

Claim 0:
1. A carburized part, a chemical composition in a region of a depth of 1.5 mm or more from a surface of the carburized part containing, by mass %,
C: 0.10 to 0.40%,
Si: 0.10 to 3.00%,
Mn: 0.50 to 3.00%,
Cr: 0.30 to 3.00%,
Al: 0.010 to 0.050%,
N: 0.003 to 0.030%,
S: 0.003 to 0.030%,
P: 0.030% or less,
Mo: 0 to 3.00%,
B: 0 to 0.0050%,
Nb: 0 to 0.100%,
Ti: 0 to 0.100%,
V: 0 to 0.30%,
Ni: 0 to 0.40%,
In: 0 to 0.02%,
Cu: 0 to 0.20%,
Bi: 0 to 0.300%,
Pb: 0 to 0.50%,
REMs: 0 to 0.020% and
a balance of Fe and impurities;
a Vickers hardness at a depth of 1.5 mm from the surface being 200 to 400 HV;
a content of C at a region of a depth down to 0.10 mm from the surface being, by mass %, 0.60 to 1.20%;
a fraction of hardened structures of an area ratio being 99.00% or more;
a grain boundary cementite fraction of an area ratio being 0.50% or less;
a fraction of incompletely hardened structures of an area ratio being 0.50% or less.