COLD FORGING AND NITRIDING STEEL, COLD FORGING AND NITRIDING STEEL MATERIAL, AND COLD FORGED AND NITRIDED COMPONENT

摘要

PROBLEM TO BE SOLVED: To provide a cold forging and nitriding steel which is excellent in cold forgeability and machinability after cold forging, and is capable of providing a cold forged and nitrided component with high core part hardness, high surface hardness and a deep effective hardened layer depth.;SOLUTION: A cold forging and nitriding steel has a chemical composition that contains, by mass, 0.01-0.15% C, less than 0.10% Si, 0.10-0.50% Mn, 0.030% or less P, 0.050% or less S, 0.80-2.0% Cr, 0.03% or more and less than 0.10% V, 0.01-0.10% Al, 0.0080% or less N, and 0.0030% or less O with the balance being Fe and impurities, and satisfies [399×C+26×Si+123×Mn+30×Cr+32×Mo+19×V≤160], [20≤(669.3×log_eC-1959.6×log_eN-6983.3)×(0.067×Mo+0.147×V)≤80] and [140×Cr+125×Al+235×V≥160]. Instead of some of Fe, a specific amount of one or more elements among Mo, Cu, Ni, Ti, Nb, Zr, Pb, Ca, Bi, Te, Se and Sb may be contained.;COPYRIGHT: (C)2013,JPO&INPIT