抄録
The fatigue limit of force-fitted specimens can be raised by induction hardening.
In order to investigate the season of this improvement, the authors carried out the fatigue test on specimens, of which the shafts were respectively as induction hardened; tempered at 40°C, or at 600°C after induction hardening; as electric furnace quenched; tempred at 600°C after electric furuace quenching or normalized; and the hardness of bosses was varied Hs 26.40 or 60.
The results show that:
i) The fatigue limit of force-fitted specimens scarcely influeuces the hardness, after different heat treatments of shafts.
ii) The residual compressive stresses and micro-structure of these shafts are more effective in improving their fatigue limits than the difference of hardness between the shaft and the boss.
iii) The fatigue limit of force-fitted specimens must be improved by induction hardening for same reason as the case of notched specimens.
