Steel for induction hardening for pinions with excellent machinability, manufacturing method thereof, and pinion with excellent bending fatigue characteristics

摘要

PPROBLEM TO BE SOLVED: To provide a steel for induction hardening for a pinion having excellent machinability for efficiently obtaining a pinion having excellent fatigue properties, and to provide a pinion having excellent bending fatigue properties obtained by subjecting the steel to induction hardening. PSOLUTION: The steel for induction hardening for a pinion having excellent machinability has a composition essentially consisting of prescribed amounts of Cr, B and Ti, containing prescribed amounts of C, Si, Mn, S, Al, P, N and Total oxygen, and comprising a prescribed amount(s) of one or more kinds selected from the group consisting of Te, Ca, Zr, Mg, Y and rare earth metals as inclusion form controlling elements, and the balance iron with inevitable impurities, and in which the average aspect ratio of MnS-containing inclusions is 10. Also, when high frequency heat treatment is performed under prescribed conditions, the steel exhibits prescribed bending fatigue properties. PCOPYRIGHT: (C)2007,JPO&INPIT