The Effect of Induction-Hardening on Fatigue Strength of Shrink-Fitted Specimen under Cyclic Direct Stress

Abstract

The present investigation has been made in order to determine the influence of induction-hardening on the fatigue strength of shrink-fitted specimens. Cyclic direct stress fatigue tests were made on shrink-fitted specimens 20mm in diameter of NiCrMo steel.
The results obtained were summarized as follows:
1. The reduction ratio 2.3 was obtained by comparing the endurance limit for a shrink-fitted specimen with that of a plain specimen.
2. The endurance limit of a shrink-fitted specimen was increased by about 2.1 times by induction-hardening.
3. The fatigue strength of the induction-hardened specimen with a shink-fitted member may be estimated approximately from the modified Goodman diagram, in which the residual compressive stress on the surface layer of specimen is assumed to be mean stress.