Rotating Bending Fatigue Tests of Steel in the Plastic Range at Elevated Temperatures

Abstract

Constant stress and constant deflexion cantilever rotating bending fatigue tests of annealed 0.35% Carbon steel were carried out at a frequency of 62rpm at the temperatures of room, 200°C, 350°C and 500°C. In the constant stress test, the change of vertical and horizontal deflexion of specimen was observed; in the constant deflexion test, the change of stress was also recorded. Consideration was given to S-N diagram, δν-N diagram, change of deflexion and stress, hysteresis energy and so on. The main conclusions of the paper are as follows : in the constant stress and constant deflexion tests, S-N diagram shows considerably same tendency; the change of deflexion and stress differs much at different temperatures, and so does hysteresis energy; the fatigue life of the constant stress test is longer than that of the constant deflexion test in the plastic range, comparing on the bases of the static bending test.