SOFT NITRIDING TREATED STEEL SUPERIOR IN WEAR RESISTANCE

摘要

PROBLEM TO BE SOLVED: To provide a soft nitriding treated steel which is superior in wear resistance, is applied mainly to automotive components, is superior in press formability, such as a total elongation property and hole enlargement property, prior to a soft nitriding treatment and has a surface hardened layer of a sufficient thickness after the soft nitriding treatment. SOLUTION: The soft nitriding treated steel contains, by mass %, 0.001 to 0.005% C, 0.03 to 0.5% Si, 0.1 to 1.0% Mn, 0.015 to 0.1% Al, 0.03 to 0.1% Ti, 0.4 to 1.4% Cr, is restricted to≤0.035% P, is composed of the balance Fe with inevitable impurities, is further 5 to 10 nm in the size in the planar direction of the Cr nitride deposited in the planar form on the ä001} face in a ferrite crystal at a depth of 0.25 mm from the extreme surface of the steel and≥1×1017cm-3in the number density of the Cr nitride, and preferably has a ratio (N/Cr) of the amount of N and the amount of Cr in the Cr nitride within the range from 0.5 to 0.8. Thus, the treated steel is superior in wear resistance. COPYRIGHT: (C)2005,JPO&NCIPI