| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a steel which is excellent in mill scale circumferential machinability, is excellent in torsional fatigue strength required for shaft parts, and is suitable as a component for machine structural applications. SOLUTION: A raw material contains, by mass, 0.35 to 0.46% C, 0.16 to 0.24% Si, >1.0 to 1.4% Mn, ≤0.025% P, >0.015 to 0.04% S, 0.21 to 0.35% Cu, >0.03 to 0.1% Al, <0.5% Cr, 0.005 to <0.04% Ti, 0.0003 to 0.0070% B, 0.002 to 0.02% N, and ≤0.0030% O, and the balance Fe and inevitable impurities. In applying hot rolling to the raw material, the raw material is heated to a temperature region of 1,100 to 1,250°C. and the rolling is ended in a temperature region of ≥1,000°C. COPYRIGHT: (C)2010,JPO&INPIT
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