Carburized parts, method for producing same and carburizing system

摘要

A carburizing method is described which is capable of dispersing cementite grains in the surface of steel uniformly and finely as not to affect fatigue strength and capable of fining the crystal grains of austenite. To prevent cementite precipitation during high temperature carburization at 980° C. or more, steel contains Al in an amount in the range of 0.05<=[Al wt %]<=2.0 and Cr in an amount in the range of 0.3<=[Cr wt %]<=4.0, and the composition of the steel satisfies the requirement represented by 1.9>=-5.6[Si wt %]-7.2[Al wt %]+1.1[Mn wt %]+2.1[Cr wt %]-0.9[Ni wt %]+1.1[Mo wt %]+0.6[W wt %]+4.3[V wt %].