Carburized steel part having excellent low cycle bending fatigue strength
View Patent ↗A carburized steel part having excellent low cycle bending fatigue strength which is comprised of a steel material which contains, by mass %, C: 0.1 to 0.6%, Si: 0.01 to 1.5%, Mn: 0.3 to 2.0, P: 0.02% or less, S: 0.001 to 0.15%, N: 0.001 to 0.03%, Al: 0.001 to 0.06%, and O: 0.005% or less and has a balance of substantially iron and unavoidable impurities and which is carburized and quenched, and then tempered, which steel part has a surface hardness of HV550 to HV800 and a core hardness of HV400 to HV500.
1. A carburized steel part having excellent low cycle bending fatigue strength which is comprised of a steel material consisting of, by mass %,
C: 0.45 to 0.6%,
Si: 0.06 to 1.5%,
Mn: 0.3 to 2.0%,
P: 0.02% or less,
S: 0.001 to 0.15%,
N: 0.001 to 0.03%,
Al: 0.001 to 0.06%,
Ti: 0.01 to 0.2%,
B: 0.0002 to 0.005%,
Cr: 1.2 to 3.0%,
Ca: 0.0002 to 0.005%,
O: 0.005% or less and
Cu: 0.1 to 2.0, and
one or both of Nb: 0.01 to 0.2% and V: 0.03 to 0.2%, and
a balance of substantially iron and unavoidable impurities,
wherein the steel material which is carburized, quenched, and then tempered,
wherein said carburized steel part has a surface hardness of HV550 to HV800, and a core hardness of HV400 to HV500.
2. The carburized steel part having excellent low cycle bending fatigue strength as set forth in claim 1 , wherein said low cycle bending fatigue strength is 20 kN or more.
3. The carburized steel part having excellent low cycle bending fatigue strength as set forth in claim 1 , wherein said carburized steel part is a differential gear or transmission gear.
4. The carburized steel part having excellent low cycle bending fatigue strength as set forth in claim 2 , wherein said carburized steel part is a differential gear or transmission gear.