Patent ID: 8123873

Claim:
A method for manufacturing a carburized part, comprising: vacuum carburizing a steel under a reduced pressure of 2 kPa or less, so that a surface carbon concentration after slow cooling performed after carburizing falls in a range of 0.9 to 1.5 mass percent, where the steel has a composition containing, by mass percent, C: 0.15 to 0.25%, Si: 0.90 to 1.30%, Mn: 0.70 to 1.10%, P: 0.030% or less, S: 0.100% or less Cu: 0.01 to 0.50%, Ni: 0.01 to 0.50%, Cr: 0.20 to 0.50%, Mo: 0.50% or less, Al: 0.30% or less, N: 0.05% or less, and a balance of Fe and unavoidable impurities, and satisfying the following Expression (1) [Si]+[Ni]+[Cu]−[Cr]>0.5 (1) (where each element symbol in Expression (1) represents a content in mass percent of the element); performing the slow cooling by air cooling at such a cooling rate that causes pearlite transformation, to transform a surface structure into pearlite; and thereafter, performing induction hardening under such heating and cooling conditions that produce fine carbides in a range of up to 0.1 mm from a surface by finely dividing cementite in the pearlite structure, where the fine carbides contain 90% or more of carbides of 1 μm or less by area ratio.