Abstract
The 0.45% carbon steel specimens, of which surface layers were perfectly quenched in various depth by induction hardening, were examined in the rotating bending fatigue test machine to ascertain the relation between fatigue endurance limit and residual stress. The result shows that both hardness pattern and residual stress together are not sufficient to be adequate to clarify the interrelations among the endurance limit, hardened depth and residual stress. Some more factors are required for the purpose. Therefore investigations must be made in that line.
