| 摘要 |
PROBLEM TO BE SOLVED: To improve the machinability of steel for Ti-added high-strength components using the driving power used for shafts, gears, etc., of automobiles, for transmission purposes. SOLUTION: The Ti-added high-strength steel having the excellent machinability contains, by mass %, 0.10 to 1.20% C, 0.05 to 1.25% Si, 0.30 to 1.50% Mn,≤0.035% P, 0.003 to 0.070% S, 0.005 to 0.050% Al, 0.10 to 0.30% Ti,≤0.015% N, 0.0005 to 0.01% Ca, and 0.0005 to 0.01% O, is composed of the balance Fe and inevitable impurities, satisfies formula (1): 100×Ti×O/Ca=1 to 100, and is generated with Ca-based sulfide or Ca-based oxide by a Ca treatment in a steel making stage of steel for machine structure purposes. COPYRIGHT: (C)2006,JPO&NCIPI
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