NITRIDING STEEL HAVING EXCELLENT MECHANICAL CHARACTERISTICS AND NITRIDING PROPERTIES

摘要

PURPOSE:To improve the mechanical characteristics such as machinability, toughness and static bendability of the nitriding steel without deteriorating the hardness of a nitriding layer or while it is improved by adding specified amounts of Nb and Pb or furthermore with Cr, Mo and V to a steel having a specified compsn. CONSTITUTION:The nitriding steel contains, by weight, 0.30 to 0.60% C, 0.10 to 0.50% Si, 0.30 to 0.90% Mn, 0.50 to 3.50% Cr, 0.50 to 1.50% Mo and 0.10 to 0.50% V as well as 0.01 to 0.10% Nb and/or 0.05 to 0.15% Pb and the balance Fe. In the steel, Nb improves its toughness and the hardness of the base metal as well as reduces the nitriding time. Pb improves its machinability as well as Cr, Mo and V increase its temper softening resistance to improve the hardness of the base metal after hardening and tempering.