STEEL EXCELLENT IN DUCTILITY AND EXCELLENT IN SURFACE HARDNESS AND INSIDE HARDNESS AFTER SOFT-NITRIDING

摘要

PROBLEM TO BE SOLVED: To provide steel having excellent ductility and hardness of ≤ a specific value by regulating the compsn. of the steel and the amt. of solid solution Cu therein to specified ranges and furthermore improved in surface hardness and inside hardness by soft-nitriding treatment. ;SOLUTION: This steel is the one having a compsn. contg., by weight, 0.0003 to 0.010% C, ≤0.050% Si, 0.10 to 0.50% Mn, ≤0.035% P, ≤0.030% S, 0.015 to 1.50% Al, ≤0.0050% N, 0.030 to 0.500% Ti, 0.8 to 2.2% Cu and Ni: 0.5×(Cu) to 1.5% Ni, furthermore contg. one or two kinds of 0.2 to 1.0% V and 0.2 to 1.5% Cr, and the balance Fe with inevitable impurities, and in which ≥0.8% Cu is allowed to enter into solid solution.;COPYRIGHT: (C)1999,JPO