Abstract
In order to examine the fine granular area (FGA) formed timing in under rotating bending fatigue for high strength steel, the rotating bending tests were carried out under decreased loads for bearing steel. The decreased loads were three conditions, the ratio of cumulative number of stress cycles at the high stress level were 2, 4, 7% against the average of the fatigue life in the interior inclusion induced fracture, and were 80% against the average of the fatigue life in the surface induced fracture. From the experimental results, FGA was observed around the inclusion. The size of FGA and the stress intensity factor range of FGA were almost similar to each other for every condition.
