PRECIPITATION HARDENING TYPE HIGH STRENGTH STEEL FOR SOFT-NITRIDING EXCELLENT IN MACHINABILITY

摘要

PURPOSE: To facilitate the machinability of a steel before soft-nitriding treatment and to improve the surface hardness and strength after soft-nitriding treatment by specifying C, Si, Mn, Ni, Al, V, Ti, Fe or the like. ;CONSTITUTION: This steel for soft-nitriding is formed of a compsn. constituted of, by weight, 0.04 to 0.4% C, 0.05 to 0.5% Si, 0.4 to 2% Mn, 0.5 to 3% Ni, 0.1 to 1.5% Al, 0.03 to 0.3% V and the balance Fe or, in addition to the above, furthermore constituted of 0.05 to 1% Ti or 0.2 to 1.5% Cr or the like. This steel for soft-nitriding can easily be machined at Hv 250 hardness before soft-nitriding. Moreover, after the soft-nitriding, its core hardness and surface hardness are high as well as its effective hardening layer is thick and strength equal to that of a carburized material can be obtd.;COPYRIGHT: (C)1993,JPO&Japio