| 摘要 |
<p>PURPOSE:To produce high strength axial parts for machine structure excellent in fatigue properties by forming steel stock having a specified componental compsn. into the shape of axial parts, thereafter subjecting then to specified induction hardening and subsequently executing specified ultrahigh induction hardening. CONSTITUTION:The componental compsn. of steel is constituted of, by weight, 0.4 to 0.7% C, <=0.1% Si, 0.3 to 0.95% Mn, 0.5 to 2% Ni and <=0.03% S, and the balance Fe with inevitable impurities. The stock of the steel is formed into the prescribed shapes of axial parts by forging, machining and form rolling. After that, they are treated by induction hardening with >=200kHz frequency so as to satisfy the formula I. In the formula I, CD denotes the depth of the hardened layer to 50% martensitic hardness and R denotes the radii of the axial parts to be subjected to the induction hardening. Moreover, 0.015 to 0.05% Al is incorporated therein. In this way, the parts optimum as pins, shafts or the like can be provided.</p> |
