Abstract
The present paper describes the fatigue behaviour of prestrained type 316 stainless steel. Two types of fatigue tests, S-N test and stress-incremental test, were performed under rotary bending using specimens subjected to 5% and 15% tensile prestrains. Fatigue strength increased with increasing prestrain, with 7% and 27% increase of fatigue limit in the 5% and 15% prestrained specimens, respectively, compared with the unprestrained specimen. The increase of fatigue strength in the prestrained specimens was attributed to higher crack initiation and small crack growth resistance. Under stress-incremental tests, the fatigue limits were increased significantly in the unprestrained and 5% prestrained specimens, but no increase was seen in the 15% prestrained specimen. Remarkable increase in hardness of failed specimens was recognized in the unprestrained and 5% prestrained specimens, while only a slight increase in the 15% prestrained specimen. It was believed, therefore, that the coaxing effect was strongly related to the ability of work hardening during stress cycling.
