| 摘要 |
PROBLEM TO BE SOLVED: To provide an age hardening type steel for soft nitriding, having excellent in machinability in a molding step, having high flex fatigue strength and excellent abrasion resistance after a soft nitriding treatment, and having no addition of Mo or reduced Mo contents.SOLUTION: An age hardening type steel for soft nitriding has a chemical composition containing C:0.05 to 0.25%, Si:0.10 to 0.40%, Mn:1.55 to 2.20%, P≤0.08%, S≤0.10%, Al:0.002 to 0.05%, Cr:0.02 to 0.30%, V:0.10 to 0.40%, Ti:0.005 to 0.10% and N≤0.015%, and the balance Fe with impurities, and having [-75+11.6×C+29.3×Mn+75.0×Cr+170×V≥0] and [0.35+0.55×C-0.25×Cr-2.5×|0.20-V|≥0]. One or more kind of Mo<0.10%, Cu≤0.30% and Ni≤0.20% may be contained in place of a portion of Fe. |
