| 摘要 |
<p>A hollow driving shaft obtained through induction hardening which contains, in terms of mass%, 0.30-0.47% carbon, up to 0.5% silicon, 0.3-2.0% manganese, up to 0.018% phosphorus, up to 0.015% sulfur, 0.15-1.0% chromium, 0.001-0.05% aluminum, 0.005-0.05% titanium, up to 0.004% calcium, up to 0.01% nitrogen, 0.0005-0.005% boron, and up to 0.0050% oxygen, satisfies the following equation (a) or (b), and has an austenite grain size number (JIS G0551) after hardening of 9 or larger. When Neff=N-14×Ti/47.9=0, then Beff=B-10.8×(N-14×Ti/47.9)/14 ··· (a). In the other case, Beff=B ··· (b). Due to the constitution, the hollow driving shaft can have all of excellent cold workability, suitability for hardening, toughness, and torsional fatigue strength and show a stable fatigue life. It is widely usable.</p> |
