Patent ID: 9469883
Filing Date: 2016-10-18
CPC Classification: C21D,C22C,C23C

Claim Text:
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.