Steel for nitriding and nitrided part

摘要

The present invention provides a steel for nitriding with a composition including, by mass %: C: 0.10% to 0.20%; Si: 0.01% to 0.7%; Mn: 0.2% to 2.0%; Cr: 0.2% to 2.5%; Al: 0.01% to less than 0.19%; V: over 0.2% to 1.0%; Mo: 0% to 0.54%; N: 0.001% to 0.01%; P limited to not more than 0.05%; S limited to not less than 0.2%; and a balance including Fe and inevitable impurities, the composition satisfying 2≦[V]/[C]≦10, where [V] is an amount of V by mass % and [C] is an amount of C by mass %, in which the steel for nitriding has a microstructure containing bainite of 50% or more in terms of an area percentage.

主权项

1. A steel for nitriding with a composition comprising, by mass %:
C: 0.10% to 0.20%; Si: 0.01% to 0.7%; Mn: 0.2% to 1.29%; Cr: 0.2% to 1.3%; Al: 0.01% to less than 0.10%; V: over 0.2% to 1.0%; Mo: 0% to 0.54%; N: 0.0034 to 0.02%; P limited to not more than 0.05%; S limited to not more than 0.20%; and a balance including Fe and inevitable impurities, the composition satisfying Expression 1, where [V] is an amount of V by mass %, and [C] is an amount of C by mass %, wherein the steel for nitriding has a microstructure containing bainite of not less than 50% in terms of an area percentage,
2≦[V]/[C]≦10  (Expression 1).